+2004-05-25 Paolo Bonzini <bonzini@gnu.org>
+
+ * Makefile.in (OBJS): Add rtlhooks.o.
+ (rtlanal.o): Depend on function.h.
+ (cse.o): Depend on rtlhooks-def.h.
+ (combine.o): Depend on rtlhooks-def.h.
+ (rtlhooks.o): New rule.
+ * combine.c: Include rtlhooks-def.h.
+ (nonzero_bits, cached_nonzero_bits, nonzero_bits1,
+ num_sign_bit_copies, cached_num_sign_bit_copies,
+ num_sign_bit_copies1): Move most of the code to rtlanal.c.
+ (reg_nonzero_bits_for_combine,
+ reg_num_sign_bit_copies_for_combine): New functions holding
+ the remnants of the above.
+ (combine_rtl_hooks): New.
+ (combine_instructions): Set rtl_hooks instead of gen_lowpart.
+ * cse.c: Include rtlhooks-def.h.
+ (cse_rtl_hooks): New.
+ (cse_main): Set rtl_hooks instead of gen_lowpart.
+ * emit-rtl.c (gen_lowpart): Remove.
+ (gen_lowpart_general): Move to rtlhooks.c.
+ * rtl.h (nonzero_bits, num_sign_bit_copies,
+ struct rtl_hooks, rtl_hooks, general_rtl_hooks): New.
+ (gen_lowpart_general): Remove.
+ (gen_lowpart): Temporarily redefine as a macro.
+ * rtlanal.c: Include function.h.
+ (nonzero_bits, cached_nonzero_bits, nonzero_bits1,
+ num_sign_bit_copies, cached_num_sign_bit_copies,
+ num_sign_bit_copies1): New, from combine.c.
+ * rtlhooks.c: New file.
+
2004-05-25 Svein E. Seldal <Svein.Seldal@solidas.com>
* config/avr/avr.h (LONG_LONG_TYPE_SIZE): Changed long long type
targhooks.o timevar.o toplev.o tracer.o tree.o tree-dump.o unroll.o \
varasm.o varray.o version.o vmsdbgout.o xcoffout.o alloc-pool.o \
et-forest.o cfghooks.o bt-load.o pretty-print.o $(GGC) web.o passes.o \
- rtl-profile.o tree-profile.o
+ rtl-profile.o tree-profile.o rtlhooks.o
OBJS-md = $(out_object_file)
OBJS-archive = $(EXTRA_OBJS) $(host_hook_obj) tree-inline.o \
$(RTL_H) $(TREE_H) hard-reg-set.h $(BASIC_BLOCK_H) real.h $(TM_P_H)
rtlanal.o : rtlanal.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) toplev.h \
$(RTL_H) hard-reg-set.h $(TM_P_H) insn-config.h $(RECOG_H) real.h flags.h \
- $(BASIC_BLOCK_H) $(REGS_H) output.h target.h
+ $(BASIC_BLOCK_H) $(REGS_H) output.h target.h function.h
errors.o : errors.c $(CONFIG_H) $(SYSTEM_H) errors.h
$(CC) -c $(ALL_CFLAGS) -DGENERATOR_FILE $(ALL_CPPFLAGS) $(INCLUDES) $< $(OUTPUT_OPTION)
cse.o : cse.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(REGS_H) \
hard-reg-set.h flags.h real.h insn-config.h $(RECOG_H) $(EXPR_H) toplev.h \
output.h function.h $(BASIC_BLOCK_H) $(GGC_H) $(TM_P_H) $(TIMEVAR_H) \
- except.h $(TARGET_H) $(PARAMS_H)
+ except.h $(TARGET_H) $(PARAMS_H) rtlhooks-def.h
web.o : web.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(REGS_H) \
hard-reg-set.h flags.h $(BASIC_BLOCK_H) function.h output.h toplev.h df.h
gcse.o : gcse.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(REGS_H) \
hard-reg-set.h $(BASIC_BLOCK_H) et-forest.h
et-forest.o : et-forest.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) et-forest.h alloc-pool.h
combine.o : combine.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) flags.h \
- function.h insn-config.h $(INSN_ATTR_H) $(REGS_H) $(EXPR_H) \
+ function.h insn-config.h $(INSN_ATTR_H) $(REGS_H) $(EXPR_H) rtlhooks-def.h \
$(BASIC_BLOCK_H) $(RECOG_H) real.h hard-reg-set.h toplev.h $(TM_P_H) $(TREE_H) $(TARGET_H)
regclass.o : regclass.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
hard-reg-set.h flags.h $(BASIC_BLOCK_H) $(REGS_H) insn-config.h $(RECOG_H) reload.h \
$(EXPR_H) $(OPTABS_H) reload.h $(REGS_H) hard-reg-set.h insn-config.h \
$(BASIC_BLOCK_H) $(RECOG_H) output.h function.h toplev.h $(TM_P_H) \
except.h $(TREE_H)
+rtlhooks.o : rtlhooks.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
+ rtlhooks-def.h $(EXPR_H)
postreload.o : postreload.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) real.h flags.h \
$(EXPR_H) $(OPTABS_H) reload.h $(REGS_H) hard-reg-set.h insn-config.h \
$(BASIC_BLOCK_H) $(RECOG_H) output.h function.h toplev.h cselib.h $(TM_P_H) \
#include "real.h"
#include "toplev.h"
#include "target.h"
+#include "rtlhooks-def.h"
/* Number of attempts to combine instructions in this function. */
#define UWIDE_SHIFT_LEFT_BY_BITS_PER_WORD(val) \
(((unsigned HOST_WIDE_INT) (val) << (BITS_PER_WORD - 1)) << 1)
-#define nonzero_bits(X, M) \
- cached_nonzero_bits (X, M, NULL_RTX, VOIDmode, 0)
-
-#define num_sign_bit_copies(X, M) \
- cached_num_sign_bit_copies (X, M, NULL_RTX, VOIDmode, 0)
-
/* Maximum register number, which is the size of the tables below. */
static unsigned int combine_max_regno;
static int n_occurrences;
+static rtx reg_nonzero_bits_for_combine (rtx, enum machine_mode, rtx,
+ enum machine_mode,
+ unsigned HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT *);
+static rtx reg_num_sign_bit_copies_for_combine (rtx, enum machine_mode, rtx,
+ enum machine_mode,
+ unsigned int, unsigned int *);
static void do_SUBST (rtx *, rtx);
static void do_SUBST_INT (int *, int);
static void init_reg_last (void);
static rtx apply_distributive_law (rtx);
static rtx simplify_and_const_int (rtx, enum machine_mode, rtx,
unsigned HOST_WIDE_INT);
-static unsigned HOST_WIDE_INT cached_nonzero_bits (rtx, enum machine_mode,
- rtx, enum machine_mode,
- unsigned HOST_WIDE_INT);
-static unsigned HOST_WIDE_INT nonzero_bits1 (rtx, enum machine_mode, rtx,
- enum machine_mode,
- unsigned HOST_WIDE_INT);
-static unsigned int cached_num_sign_bit_copies (rtx, enum machine_mode, rtx,
- enum machine_mode,
- unsigned int);
-static unsigned int num_sign_bit_copies1 (rtx, enum machine_mode, rtx,
- enum machine_mode, unsigned int);
static int merge_outer_ops (enum rtx_code *, HOST_WIDE_INT *, enum rtx_code,
HOST_WIDE_INT, enum machine_mode, int *);
static rtx simplify_shift_const (rtx, enum rtx_code, enum machine_mode, rtx,
static enum rtx_code combine_reversed_comparison_code (rtx);
static int unmentioned_reg_p_1 (rtx *, void *);
static bool unmentioned_reg_p (rtx, rtx);
+\f
+
+/* It is not safe to use ordinary gen_lowpart in combine.
+ See comments in gen_lowpart_for_combine. */
+#undef RTL_HOOKS_GEN_LOWPART
+#define RTL_HOOKS_GEN_LOWPART gen_lowpart_for_combine
+
+#undef RTL_HOOKS_REG_NONZERO_REG_BITS
+#define RTL_HOOKS_REG_NONZERO_REG_BITS reg_nonzero_bits_for_combine
+
+#undef RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES
+#define RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES reg_num_sign_bit_copies_for_combine
+
+static const struct rtl_hooks combine_rtl_hooks = RTL_HOOKS_INITIALIZER;
+
\f
/* Substitute NEWVAL, an rtx expression, into INTO, a place in some
insn. The substitution can be undone by undo_all. If INTO is already
combine_max_regno = nregs;
- /* It is not safe to use ordinary gen_lowpart in combine.
- See comments in gen_lowpart_for_combine. */
- gen_lowpart = gen_lowpart_for_combine;
+ rtl_hooks = combine_rtl_hooks;
reg_stat = xcalloc (nregs, sizeof (struct reg_stat));
total_successes += combine_successes;
nonzero_sign_valid = 0;
- gen_lowpart = gen_lowpart_general;
+ rtl_hooks = general_rtl_hooks;
/* Make recognizer allow volatile MEMs again. */
init_recog ();
return x;
}
\f
-#define nonzero_bits_with_known(X, MODE) \
- cached_nonzero_bits (X, MODE, known_x, known_mode, known_ret)
-
-/* The function cached_nonzero_bits is a wrapper around nonzero_bits1.
- It avoids exponential behavior in nonzero_bits1 when X has
- identical subexpressions on the first or the second level. */
-
-static unsigned HOST_WIDE_INT
-cached_nonzero_bits (rtx x, enum machine_mode mode, rtx known_x,
- enum machine_mode known_mode,
- unsigned HOST_WIDE_INT known_ret)
-{
- if (x == known_x && mode == known_mode)
- return known_ret;
-
- /* Try to find identical subexpressions. If found call
- nonzero_bits1 on X with the subexpressions as KNOWN_X and the
- precomputed value for the subexpression as KNOWN_RET. */
-
- if (ARITHMETIC_P (x))
- {
- rtx x0 = XEXP (x, 0);
- rtx x1 = XEXP (x, 1);
-
- /* Check the first level. */
- if (x0 == x1)
- return nonzero_bits1 (x, mode, x0, mode,
- nonzero_bits_with_known (x0, mode));
-
- /* Check the second level. */
- if (ARITHMETIC_P (x0)
- && (x1 == XEXP (x0, 0) || x1 == XEXP (x0, 1)))
- return nonzero_bits1 (x, mode, x1, mode,
- nonzero_bits_with_known (x1, mode));
-
- if (ARITHMETIC_P (x1)
- && (x0 == XEXP (x1, 0) || x0 == XEXP (x1, 1)))
- return nonzero_bits1 (x, mode, x0, mode,
- nonzero_bits_with_known (x0, mode));
- }
-
- return nonzero_bits1 (x, mode, known_x, known_mode, known_ret);
-}
-
-/* We let num_sign_bit_copies recur into nonzero_bits as that is useful.
- We don't let nonzero_bits recur into num_sign_bit_copies, because that
- is less useful. We can't allow both, because that results in exponential
- run time recursion. There is a nullstone testcase that triggered
- this. This macro avoids accidental uses of num_sign_bit_copies. */
-#define cached_num_sign_bit_copies()
-
-/* Given an expression, X, compute which bits in X can be nonzero.
+/* Given a REG, X, compute which bits in X can be nonzero.
We don't care about bits outside of those defined in MODE.
For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is
a shift, AND, or zero_extract, we can do better. */
-static unsigned HOST_WIDE_INT
-nonzero_bits1 (rtx x, enum machine_mode mode, rtx known_x,
- enum machine_mode known_mode,
- unsigned HOST_WIDE_INT known_ret)
+static rtx
+reg_nonzero_bits_for_combine (rtx x, enum machine_mode mode,
+ rtx known_x ATTRIBUTE_UNUSED,
+ enum machine_mode known_mode ATTRIBUTE_UNUSED,
+ unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED,
+ unsigned HOST_WIDE_INT *nonzero)
{
- unsigned HOST_WIDE_INT nonzero = GET_MODE_MASK (mode);
- unsigned HOST_WIDE_INT inner_nz;
- enum rtx_code code;
- unsigned int mode_width = GET_MODE_BITSIZE (mode);
rtx tem;
- /* For floating-point values, assume all bits are needed. */
- if (FLOAT_MODE_P (GET_MODE (x)) || FLOAT_MODE_P (mode))
- return nonzero;
+ /* If X is a register whose nonzero bits value is current, use it.
+ Otherwise, if X is a register whose value we can find, use that
+ value. Otherwise, use the previously-computed global nonzero bits
+ for this register. */
- /* If X is wider than MODE, use its mode instead. */
- if (GET_MODE_BITSIZE (GET_MODE (x)) > mode_width)
+ if (reg_stat[REGNO (x)].last_set_value != 0
+ && (reg_stat[REGNO (x)].last_set_mode == mode
+ || (GET_MODE_CLASS (reg_stat[REGNO (x)].last_set_mode) == MODE_INT
+ && GET_MODE_CLASS (mode) == MODE_INT))
+ && (reg_stat[REGNO (x)].last_set_label == label_tick
+ || (REGNO (x) >= FIRST_PSEUDO_REGISTER
+ && REG_N_SETS (REGNO (x)) == 1
+ && ! REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start,
+ REGNO (x))))
+ && INSN_CUID (reg_stat[REGNO (x)].last_set) < subst_low_cuid)
{
- mode = GET_MODE (x);
- nonzero = GET_MODE_MASK (mode);
- mode_width = GET_MODE_BITSIZE (mode);
+ *nonzero &= reg_stat[REGNO (x)].last_set_nonzero_bits;
+ return NULL;
}
- if (mode_width > HOST_BITS_PER_WIDE_INT)
- /* Our only callers in this case look for single bit values. So
- just return the mode mask. Those tests will then be false. */
- return nonzero;
-
-#ifndef WORD_REGISTER_OPERATIONS
- /* If MODE is wider than X, but both are a single word for both the host
- and target machines, we can compute this from which bits of the
- object might be nonzero in its own mode, taking into account the fact
- that on many CISC machines, accessing an object in a wider mode
- causes the high-order bits to become undefined. So they are
- not known to be zero. */
-
- if (GET_MODE (x) != VOIDmode && GET_MODE (x) != mode
- && GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD
- && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT
- && GET_MODE_BITSIZE (mode) > GET_MODE_BITSIZE (GET_MODE (x)))
- {
- nonzero &= nonzero_bits_with_known (x, GET_MODE (x));
- nonzero |= GET_MODE_MASK (mode) & ~GET_MODE_MASK (GET_MODE (x));
- return nonzero;
- }
-#endif
+ tem = get_last_value (x);
- code = GET_CODE (x);
- switch (code)
+ if (tem)
{
- case REG:
-#if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend)
- /* If pointers extend unsigned and this is a pointer in Pmode, say that
- all the bits above ptr_mode are known to be zero. */
- if (POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode
- && REG_POINTER (x))
- nonzero &= GET_MODE_MASK (ptr_mode);
-#endif
-
- /* Include declared information about alignment of pointers. */
- /* ??? We don't properly preserve REG_POINTER changes across
- pointer-to-integer casts, so we can't trust it except for
- things that we know must be pointers. See execute/960116-1.c. */
- if ((x == stack_pointer_rtx
- || x == frame_pointer_rtx
- || x == arg_pointer_rtx)
- && REGNO_POINTER_ALIGN (REGNO (x)))
- {
- unsigned HOST_WIDE_INT alignment
- = REGNO_POINTER_ALIGN (REGNO (x)) / BITS_PER_UNIT;
-
-#ifdef PUSH_ROUNDING
- /* If PUSH_ROUNDING is defined, it is possible for the
- stack to be momentarily aligned only to that amount,
- so we pick the least alignment. */
- if (x == stack_pointer_rtx && PUSH_ARGS)
- alignment = MIN ((unsigned HOST_WIDE_INT) PUSH_ROUNDING (1),
- alignment);
-#endif
-
- nonzero &= ~(alignment - 1);
- }
-
- /* If X is a register whose nonzero bits value is current, use it.
- Otherwise, if X is a register whose value we can find, use that
- value. Otherwise, use the previously-computed global nonzero bits
- for this register. */
-
- if (reg_stat[REGNO (x)].last_set_value != 0
- && (reg_stat[REGNO (x)].last_set_mode == mode
- || (GET_MODE_CLASS (reg_stat[REGNO (x)].last_set_mode) == MODE_INT
- && GET_MODE_CLASS (mode) == MODE_INT))
- && (reg_stat[REGNO (x)].last_set_label == label_tick
- || (REGNO (x) >= FIRST_PSEUDO_REGISTER
- && REG_N_SETS (REGNO (x)) == 1
- && ! REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start,
- REGNO (x))))
- && INSN_CUID (reg_stat[REGNO (x)].last_set) < subst_low_cuid)
- return reg_stat[REGNO (x)].last_set_nonzero_bits & nonzero;
-
- tem = get_last_value (x);
-
- if (tem)
- {
-#ifdef SHORT_IMMEDIATES_SIGN_EXTEND
- /* If X is narrower than MODE and TEM is a non-negative
- constant that would appear negative in the mode of X,
- sign-extend it for use in reg_stat[].nonzero_bits because
- some machines (maybe most) will actually do the sign-extension
- and this is the conservative approach.
-
- ??? For 2.5, try to tighten up the MD files in this regard
- instead of this kludge. */
-
- if (GET_MODE_BITSIZE (GET_MODE (x)) < mode_width
- && GET_CODE (tem) == CONST_INT
- && INTVAL (tem) > 0
- && 0 != (INTVAL (tem)
- & ((HOST_WIDE_INT) 1
- << (GET_MODE_BITSIZE (GET_MODE (x)) - 1))))
- tem = GEN_INT (INTVAL (tem)
- | ((HOST_WIDE_INT) (-1)
- << GET_MODE_BITSIZE (GET_MODE (x))));
-#endif
- return nonzero_bits_with_known (tem, mode) & nonzero;
- }
- else if (nonzero_sign_valid && reg_stat[REGNO (x)].nonzero_bits)
- {
- unsigned HOST_WIDE_INT mask = reg_stat[REGNO (x)].nonzero_bits;
-
- if (GET_MODE_BITSIZE (GET_MODE (x)) < mode_width)
- /* We don't know anything about the upper bits. */
- mask |= GET_MODE_MASK (mode) ^ GET_MODE_MASK (GET_MODE (x));
- return nonzero & mask;
- }
- else
- return nonzero;
-
- case CONST_INT:
#ifdef SHORT_IMMEDIATES_SIGN_EXTEND
- /* If X is negative in MODE, sign-extend the value. */
- if (INTVAL (x) > 0 && mode_width < BITS_PER_WORD
- && 0 != (INTVAL (x) & ((HOST_WIDE_INT) 1 << (mode_width - 1))))
- return (INTVAL (x) | ((HOST_WIDE_INT) (-1) << mode_width));
-#endif
-
- return INTVAL (x);
-
- case MEM:
-#ifdef LOAD_EXTEND_OP
- /* In many, if not most, RISC machines, reading a byte from memory
- zeros the rest of the register. Noticing that fact saves a lot
- of extra zero-extends. */
- if (LOAD_EXTEND_OP (GET_MODE (x)) == ZERO_EXTEND)
- nonzero &= GET_MODE_MASK (GET_MODE (x));
-#endif
- break;
-
- case EQ: case NE:
- case UNEQ: case LTGT:
- case GT: case GTU: case UNGT:
- case LT: case LTU: case UNLT:
- case GE: case GEU: case UNGE:
- case LE: case LEU: case UNLE:
- case UNORDERED: case ORDERED:
-
- /* If this produces an integer result, we know which bits are set.
- Code here used to clear bits outside the mode of X, but that is
- now done above. */
-
- if (GET_MODE_CLASS (mode) == MODE_INT
- && mode_width <= HOST_BITS_PER_WIDE_INT)
- nonzero = STORE_FLAG_VALUE;
- break;
-
- case NEG:
-#if 0
- /* Disabled to avoid exponential mutual recursion between nonzero_bits
- and num_sign_bit_copies. */
- if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x))
- == GET_MODE_BITSIZE (GET_MODE (x)))
- nonzero = 1;
-#endif
-
- if (GET_MODE_SIZE (GET_MODE (x)) < mode_width)
- nonzero |= (GET_MODE_MASK (mode) & ~GET_MODE_MASK (GET_MODE (x)));
- break;
-
- case ABS:
-#if 0
- /* Disabled to avoid exponential mutual recursion between nonzero_bits
- and num_sign_bit_copies. */
- if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x))
- == GET_MODE_BITSIZE (GET_MODE (x)))
- nonzero = 1;
-#endif
- break;
-
- case TRUNCATE:
- nonzero &= (nonzero_bits_with_known (XEXP (x, 0), mode)
- & GET_MODE_MASK (mode));
- break;
-
- case ZERO_EXTEND:
- nonzero &= nonzero_bits_with_known (XEXP (x, 0), mode);
- if (GET_MODE (XEXP (x, 0)) != VOIDmode)
- nonzero &= GET_MODE_MASK (GET_MODE (XEXP (x, 0)));
- break;
-
- case SIGN_EXTEND:
- /* If the sign bit is known clear, this is the same as ZERO_EXTEND.
- Otherwise, show all the bits in the outer mode but not the inner
- may be nonzero. */
- inner_nz = nonzero_bits_with_known (XEXP (x, 0), mode);
- if (GET_MODE (XEXP (x, 0)) != VOIDmode)
- {
- inner_nz &= GET_MODE_MASK (GET_MODE (XEXP (x, 0)));
- if (inner_nz
- & (((HOST_WIDE_INT) 1
- << (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - 1))))
- inner_nz |= (GET_MODE_MASK (mode)
- & ~GET_MODE_MASK (GET_MODE (XEXP (x, 0))));
- }
-
- nonzero &= inner_nz;
- break;
-
- case AND:
- nonzero &= (nonzero_bits_with_known (XEXP (x, 0), mode)
- & nonzero_bits_with_known (XEXP (x, 1), mode));
- break;
-
- case XOR: case IOR:
- case UMIN: case UMAX: case SMIN: case SMAX:
- {
- unsigned HOST_WIDE_INT nonzero0 =
- nonzero_bits_with_known (XEXP (x, 0), mode);
-
- /* Don't call nonzero_bits for the second time if it cannot change
- anything. */
- if ((nonzero & nonzero0) != nonzero)
- nonzero &= (nonzero0
- | nonzero_bits_with_known (XEXP (x, 1), mode));
- }
- break;
-
- case PLUS: case MINUS:
- case MULT:
- case DIV: case UDIV:
- case MOD: case UMOD:
- /* We can apply the rules of arithmetic to compute the number of
- high- and low-order zero bits of these operations. We start by
- computing the width (position of the highest-order nonzero bit)
- and the number of low-order zero bits for each value. */
- {
- unsigned HOST_WIDE_INT nz0 =
- nonzero_bits_with_known (XEXP (x, 0), mode);
- unsigned HOST_WIDE_INT nz1 =
- nonzero_bits_with_known (XEXP (x, 1), mode);
- int sign_index = GET_MODE_BITSIZE (GET_MODE (x)) - 1;
- int width0 = floor_log2 (nz0) + 1;
- int width1 = floor_log2 (nz1) + 1;
- int low0 = floor_log2 (nz0 & -nz0);
- int low1 = floor_log2 (nz1 & -nz1);
- HOST_WIDE_INT op0_maybe_minusp
- = (nz0 & ((HOST_WIDE_INT) 1 << sign_index));
- HOST_WIDE_INT op1_maybe_minusp
- = (nz1 & ((HOST_WIDE_INT) 1 << sign_index));
- unsigned int result_width = mode_width;
- int result_low = 0;
-
- switch (code)
- {
- case PLUS:
- result_width = MAX (width0, width1) + 1;
- result_low = MIN (low0, low1);
- break;
- case MINUS:
- result_low = MIN (low0, low1);
- break;
- case MULT:
- result_width = width0 + width1;
- result_low = low0 + low1;
- break;
- case DIV:
- if (width1 == 0)
- break;
- if (! op0_maybe_minusp && ! op1_maybe_minusp)
- result_width = width0;
- break;
- case UDIV:
- if (width1 == 0)
- break;
- result_width = width0;
- break;
- case MOD:
- if (width1 == 0)
- break;
- if (! op0_maybe_minusp && ! op1_maybe_minusp)
- result_width = MIN (width0, width1);
- result_low = MIN (low0, low1);
- break;
- case UMOD:
- if (width1 == 0)
- break;
- result_width = MIN (width0, width1);
- result_low = MIN (low0, low1);
- break;
- default:
- abort ();
- }
-
- if (result_width < mode_width)
- nonzero &= ((HOST_WIDE_INT) 1 << result_width) - 1;
-
- if (result_low > 0)
- nonzero &= ~(((HOST_WIDE_INT) 1 << result_low) - 1);
-
-#ifdef POINTERS_EXTEND_UNSIGNED
- /* If pointers extend unsigned and this is an addition or subtraction
- to a pointer in Pmode, all the bits above ptr_mode are known to be
- zero. */
- if (POINTERS_EXTEND_UNSIGNED > 0 && GET_MODE (x) == Pmode
- && (code == PLUS || code == MINUS)
- && GET_CODE (XEXP (x, 0)) == REG && REG_POINTER (XEXP (x, 0)))
- nonzero &= GET_MODE_MASK (ptr_mode);
-#endif
- }
- break;
-
- case ZERO_EXTRACT:
- if (GET_CODE (XEXP (x, 1)) == CONST_INT
- && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT)
- nonzero &= ((HOST_WIDE_INT) 1 << INTVAL (XEXP (x, 1))) - 1;
- break;
-
- case SUBREG:
- /* If this is a SUBREG formed for a promoted variable that has
- been zero-extended, we know that at least the high-order bits
- are zero, though others might be too. */
-
- if (SUBREG_PROMOTED_VAR_P (x) && SUBREG_PROMOTED_UNSIGNED_P (x) > 0)
- nonzero = (GET_MODE_MASK (GET_MODE (x))
- & nonzero_bits_with_known (SUBREG_REG (x), GET_MODE (x)));
-
- /* If the inner mode is a single word for both the host and target
- machines, we can compute this from which bits of the inner
- object might be nonzero. */
- if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) <= BITS_PER_WORD
- && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))
- <= HOST_BITS_PER_WIDE_INT))
- {
- nonzero &= nonzero_bits_with_known (SUBREG_REG (x), mode);
-
-#if defined (WORD_REGISTER_OPERATIONS) && defined (LOAD_EXTEND_OP)
- /* If this is a typical RISC machine, we only have to worry
- about the way loads are extended. */
- if ((LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) == SIGN_EXTEND
- ? (((nonzero
- & (((unsigned HOST_WIDE_INT) 1
- << (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) - 1))))
- != 0))
- : LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) != ZERO_EXTEND)
- || GET_CODE (SUBREG_REG (x)) != MEM)
+ /* If X is narrower than MODE and TEM is a non-negative
+ constant that would appear negative in the mode of X,
+ sign-extend it for use in reg_nonzero_bits because some
+ machines (maybe most) will actually do the sign-extension
+ and this is the conservative approach.
+
+ ??? For 2.5, try to tighten up the MD files in this regard
+ instead of this kludge. */
+
+ if (GET_MODE_BITSIZE (GET_MODE (x)) < GET_MODE_BITSIZE (mode)
+ && GET_CODE (tem) == CONST_INT
+ && INTVAL (tem) > 0
+ && 0 != (INTVAL (tem)
+ & ((HOST_WIDE_INT) 1
+ << (GET_MODE_BITSIZE (GET_MODE (x)) - 1))))
+ tem = GEN_INT (INTVAL (tem)
+ | ((HOST_WIDE_INT) (-1)
+ << GET_MODE_BITSIZE (GET_MODE (x))));
#endif
- {
- /* On many CISC machines, accessing an object in a wider mode
- causes the high-order bits to become undefined. So they are
- not known to be zero. */
- if (GET_MODE_SIZE (GET_MODE (x))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
- nonzero |= (GET_MODE_MASK (GET_MODE (x))
- & ~GET_MODE_MASK (GET_MODE (SUBREG_REG (x))));
- }
- }
- break;
-
- case ASHIFTRT:
- case LSHIFTRT:
- case ASHIFT:
- case ROTATE:
- /* The nonzero bits are in two classes: any bits within MODE
- that aren't in GET_MODE (x) are always significant. The rest of the
- nonzero bits are those that are significant in the operand of
- the shift when shifted the appropriate number of bits. This
- shows that high-order bits are cleared by the right shift and
- low-order bits by left shifts. */
- if (GET_CODE (XEXP (x, 1)) == CONST_INT
- && INTVAL (XEXP (x, 1)) >= 0
- && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT)
- {
- enum machine_mode inner_mode = GET_MODE (x);
- unsigned int width = GET_MODE_BITSIZE (inner_mode);
- int count = INTVAL (XEXP (x, 1));
- unsigned HOST_WIDE_INT mode_mask = GET_MODE_MASK (inner_mode);
- unsigned HOST_WIDE_INT op_nonzero =
- nonzero_bits_with_known (XEXP (x, 0), mode);
- unsigned HOST_WIDE_INT inner = op_nonzero & mode_mask;
- unsigned HOST_WIDE_INT outer = 0;
-
- if (mode_width > width)
- outer = (op_nonzero & nonzero & ~mode_mask);
-
- if (code == LSHIFTRT)
- inner >>= count;
- else if (code == ASHIFTRT)
- {
- inner >>= count;
-
- /* If the sign bit may have been nonzero before the shift, we
- need to mark all the places it could have been copied to
- by the shift as possibly nonzero. */
- if (inner & ((HOST_WIDE_INT) 1 << (width - 1 - count)))
- inner |= (((HOST_WIDE_INT) 1 << count) - 1) << (width - count);
- }
- else if (code == ASHIFT)
- inner <<= count;
- else
- inner = ((inner << (count % width)
- | (inner >> (width - (count % width)))) & mode_mask);
-
- nonzero &= (outer | inner);
- }
- break;
-
- case FFS:
- case POPCOUNT:
- /* This is at most the number of bits in the mode. */
- nonzero = ((HOST_WIDE_INT) 2 << (floor_log2 (mode_width))) - 1;
- break;
-
- case CLZ:
- /* If CLZ has a known value at zero, then the nonzero bits are
- that value, plus the number of bits in the mode minus one. */
- if (CLZ_DEFINED_VALUE_AT_ZERO (mode, nonzero))
- nonzero |= ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width))) - 1;
- else
- nonzero = -1;
- break;
-
- case CTZ:
- /* If CTZ has a known value at zero, then the nonzero bits are
- that value, plus the number of bits in the mode minus one. */
- if (CTZ_DEFINED_VALUE_AT_ZERO (mode, nonzero))
- nonzero |= ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width))) - 1;
- else
- nonzero = -1;
- break;
-
- case PARITY:
- nonzero = 1;
- break;
-
- case IF_THEN_ELSE:
- nonzero &= (nonzero_bits_with_known (XEXP (x, 1), mode)
- | nonzero_bits_with_known (XEXP (x, 2), mode));
- break;
-
- default:
- break;
+ return tem;
}
-
- return nonzero;
-}
-
-/* See the macro definition above. */
-#undef cached_num_sign_bit_copies
-\f
-#define num_sign_bit_copies_with_known(X, M) \
- cached_num_sign_bit_copies (X, M, known_x, known_mode, known_ret)
-
-/* The function cached_num_sign_bit_copies is a wrapper around
- num_sign_bit_copies1. It avoids exponential behavior in
- num_sign_bit_copies1 when X has identical subexpressions on the
- first or the second level. */
-
-static unsigned int
-cached_num_sign_bit_copies (rtx x, enum machine_mode mode, rtx known_x,
- enum machine_mode known_mode,
- unsigned int known_ret)
-{
- if (x == known_x && mode == known_mode)
- return known_ret;
-
- /* Try to find identical subexpressions. If found call
- num_sign_bit_copies1 on X with the subexpressions as KNOWN_X and
- the precomputed value for the subexpression as KNOWN_RET. */
-
- if (ARITHMETIC_P (x))
+ else if (nonzero_sign_valid && reg_stat[REGNO (x)].nonzero_bits)
{
- rtx x0 = XEXP (x, 0);
- rtx x1 = XEXP (x, 1);
-
- /* Check the first level. */
- if (x0 == x1)
- return
- num_sign_bit_copies1 (x, mode, x0, mode,
- num_sign_bit_copies_with_known (x0, mode));
-
- /* Check the second level. */
- if (ARITHMETIC_P (x0)
- && (x1 == XEXP (x0, 0) || x1 == XEXP (x0, 1)))
- return
- num_sign_bit_copies1 (x, mode, x1, mode,
- num_sign_bit_copies_with_known (x1, mode));
+ unsigned HOST_WIDE_INT mask = reg_stat[REGNO (x)].nonzero_bits;
- if (ARITHMETIC_P (x1)
- && (x0 == XEXP (x1, 0) || x0 == XEXP (x1, 1)))
- return
- num_sign_bit_copies1 (x, mode, x0, mode,
- num_sign_bit_copies_with_known (x0, mode));
+ if (GET_MODE_BITSIZE (GET_MODE (x)) < GET_MODE_BITSIZE (mode))
+ /* We don't know anything about the upper bits. */
+ mask |= GET_MODE_MASK (mode) ^ GET_MODE_MASK (GET_MODE (x));
+ *nonzero &= mask;
}
- return num_sign_bit_copies1 (x, mode, known_x, known_mode, known_ret);
+ return NULL;
}
/* Return the number of bits at the high-order end of X that are known to
VOIDmode, X will be used in its own mode. The returned value will always
be between 1 and the number of bits in MODE. */
-static unsigned int
-num_sign_bit_copies1 (rtx x, enum machine_mode mode, rtx known_x,
- enum machine_mode known_mode,
- unsigned int known_ret)
+static rtx
+reg_num_sign_bit_copies_for_combine (rtx x, enum machine_mode mode,
+ rtx known_x ATTRIBUTE_UNUSED,
+ enum machine_mode known_mode
+ ATTRIBUTE_UNUSED,
+ unsigned int known_ret ATTRIBUTE_UNUSED,
+ unsigned int *result)
{
- enum rtx_code code = GET_CODE (x);
- unsigned int bitwidth;
- int num0, num1, result;
- unsigned HOST_WIDE_INT nonzero;
rtx tem;
- /* If we weren't given a mode, use the mode of X. If the mode is still
- VOIDmode, we don't know anything. Likewise if one of the modes is
- floating-point. */
-
- if (mode == VOIDmode)
- mode = GET_MODE (x);
-
- if (mode == VOIDmode || FLOAT_MODE_P (mode) || FLOAT_MODE_P (GET_MODE (x)))
- return 1;
-
- bitwidth = GET_MODE_BITSIZE (mode);
-
- /* For a smaller object, just ignore the high bits. */
- if (bitwidth < GET_MODE_BITSIZE (GET_MODE (x)))
+ if (reg_stat[REGNO (x)].last_set_value != 0
+ && reg_stat[REGNO (x)].last_set_mode == mode
+ && (reg_stat[REGNO (x)].last_set_label == label_tick
+ || (REGNO (x) >= FIRST_PSEUDO_REGISTER
+ && REG_N_SETS (REGNO (x)) == 1
+ && ! REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start,
+ REGNO (x))))
+ && INSN_CUID (reg_stat[REGNO (x)].last_set) < subst_low_cuid)
{
- num0 = num_sign_bit_copies_with_known (x, GET_MODE (x));
- return MAX (1,
- num0 - (int) (GET_MODE_BITSIZE (GET_MODE (x)) - bitwidth));
- }
-
- if (GET_MODE (x) != VOIDmode && bitwidth > GET_MODE_BITSIZE (GET_MODE (x)))
- {
-#ifndef WORD_REGISTER_OPERATIONS
- /* If this machine does not do all register operations on the entire
- register and MODE is wider than the mode of X, we can say nothing
- at all about the high-order bits. */
- return 1;
-#else
- /* Likewise on machines that do, if the mode of the object is smaller
- than a word and loads of that size don't sign extend, we can say
- nothing about the high order bits. */
- if (GET_MODE_BITSIZE (GET_MODE (x)) < BITS_PER_WORD
-#ifdef LOAD_EXTEND_OP
- && LOAD_EXTEND_OP (GET_MODE (x)) != SIGN_EXTEND
-#endif
- )
- return 1;
-#endif
+ *result = reg_stat[REGNO (x)].last_set_sign_bit_copies;
+ return NULL;
}
- switch (code)
- {
- case REG:
+ tem = get_last_value (x);
+ if (tem != 0)
+ return tem;
-#if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend)
- /* If pointers extend signed and this is a pointer in Pmode, say that
- all the bits above ptr_mode are known to be sign bit copies. */
- if (! POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode && mode == Pmode
- && REG_POINTER (x))
- return GET_MODE_BITSIZE (Pmode) - GET_MODE_BITSIZE (ptr_mode) + 1;
-#endif
-
- if (reg_stat[REGNO (x)].last_set_value != 0
- && reg_stat[REGNO (x)].last_set_mode == mode
- && (reg_stat[REGNO (x)].last_set_label == label_tick
- || (REGNO (x) >= FIRST_PSEUDO_REGISTER
- && REG_N_SETS (REGNO (x)) == 1
- && ! REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start,
- REGNO (x))))
- && INSN_CUID (reg_stat[REGNO (x)].last_set) < subst_low_cuid)
- return reg_stat[REGNO (x)].last_set_sign_bit_copies;
-
- tem = get_last_value (x);
- if (tem != 0)
- return num_sign_bit_copies_with_known (tem, mode);
-
- if (nonzero_sign_valid && reg_stat[REGNO (x)].sign_bit_copies != 0
- && GET_MODE_BITSIZE (GET_MODE (x)) == bitwidth)
- return reg_stat[REGNO (x)].sign_bit_copies;
- break;
-
- case MEM:
-#ifdef LOAD_EXTEND_OP
- /* Some RISC machines sign-extend all loads of smaller than a word. */
- if (LOAD_EXTEND_OP (GET_MODE (x)) == SIGN_EXTEND)
- return MAX (1, ((int) bitwidth
- - (int) GET_MODE_BITSIZE (GET_MODE (x)) + 1));
-#endif
- break;
-
- case CONST_INT:
- /* If the constant is negative, take its 1's complement and remask.
- Then see how many zero bits we have. */
- nonzero = INTVAL (x) & GET_MODE_MASK (mode);
- if (bitwidth <= HOST_BITS_PER_WIDE_INT
- && (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
- nonzero = (~nonzero) & GET_MODE_MASK (mode);
-
- return (nonzero == 0 ? bitwidth : bitwidth - floor_log2 (nonzero) - 1);
-
- case SUBREG:
- /* If this is a SUBREG for a promoted object that is sign-extended
- and we are looking at it in a wider mode, we know that at least the
- high-order bits are known to be sign bit copies. */
-
- if (SUBREG_PROMOTED_VAR_P (x) && ! SUBREG_PROMOTED_UNSIGNED_P (x))
- {
- num0 = num_sign_bit_copies_with_known (SUBREG_REG (x), mode);
- return MAX ((int) bitwidth
- - (int) GET_MODE_BITSIZE (GET_MODE (x)) + 1,
- num0);
- }
-
- /* For a smaller object, just ignore the high bits. */
- if (bitwidth <= GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))))
- {
- num0 = num_sign_bit_copies_with_known (SUBREG_REG (x), VOIDmode);
- return MAX (1, (num0
- - (int) (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))
- - bitwidth)));
- }
-
-#ifdef WORD_REGISTER_OPERATIONS
-#ifdef LOAD_EXTEND_OP
- /* For paradoxical SUBREGs on machines where all register operations
- affect the entire register, just look inside. Note that we are
- passing MODE to the recursive call, so the number of sign bit copies
- will remain relative to that mode, not the inner mode. */
-
- /* This works only if loads sign extend. Otherwise, if we get a
- reload for the inner part, it may be loaded from the stack, and
- then we lose all sign bit copies that existed before the store
- to the stack. */
-
- if ((GET_MODE_SIZE (GET_MODE (x))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
- && LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) == SIGN_EXTEND
- && GET_CODE (SUBREG_REG (x)) == MEM)
- return num_sign_bit_copies_with_known (SUBREG_REG (x), mode);
-#endif
-#endif
- break;
-
- case SIGN_EXTRACT:
- if (GET_CODE (XEXP (x, 1)) == CONST_INT)
- return MAX (1, (int) bitwidth - INTVAL (XEXP (x, 1)));
- break;
-
- case SIGN_EXTEND:
- return (bitwidth - GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))
- + num_sign_bit_copies_with_known (XEXP (x, 0), VOIDmode));
-
- case TRUNCATE:
- /* For a smaller object, just ignore the high bits. */
- num0 = num_sign_bit_copies_with_known (XEXP (x, 0), VOIDmode);
- return MAX (1, (num0 - (int) (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))
- - bitwidth)));
-
- case NOT:
- return num_sign_bit_copies_with_known (XEXP (x, 0), mode);
-
- case ROTATE: case ROTATERT:
- /* If we are rotating left by a number of bits less than the number
- of sign bit copies, we can just subtract that amount from the
- number. */
- if (GET_CODE (XEXP (x, 1)) == CONST_INT
- && INTVAL (XEXP (x, 1)) >= 0
- && INTVAL (XEXP (x, 1)) < (int) bitwidth)
- {
- num0 = num_sign_bit_copies_with_known (XEXP (x, 0), mode);
- return MAX (1, num0 - (code == ROTATE ? INTVAL (XEXP (x, 1))
- : (int) bitwidth - INTVAL (XEXP (x, 1))));
- }
- break;
-
- case NEG:
- /* In general, this subtracts one sign bit copy. But if the value
- is known to be positive, the number of sign bit copies is the
- same as that of the input. Finally, if the input has just one bit
- that might be nonzero, all the bits are copies of the sign bit. */
- num0 = num_sign_bit_copies_with_known (XEXP (x, 0), mode);
- if (bitwidth > HOST_BITS_PER_WIDE_INT)
- return num0 > 1 ? num0 - 1 : 1;
-
- nonzero = nonzero_bits (XEXP (x, 0), mode);
- if (nonzero == 1)
- return bitwidth;
-
- if (num0 > 1
- && (((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero))
- num0--;
-
- return num0;
-
- case IOR: case AND: case XOR:
- case SMIN: case SMAX: case UMIN: case UMAX:
- /* Logical operations will preserve the number of sign-bit copies.
- MIN and MAX operations always return one of the operands. */
- num0 = num_sign_bit_copies_with_known (XEXP (x, 0), mode);
- num1 = num_sign_bit_copies_with_known (XEXP (x, 1), mode);
- return MIN (num0, num1);
-
- case PLUS: case MINUS:
- /* For addition and subtraction, we can have a 1-bit carry. However,
- if we are subtracting 1 from a positive number, there will not
- be such a carry. Furthermore, if the positive number is known to
- be 0 or 1, we know the result is either -1 or 0. */
-
- if (code == PLUS && XEXP (x, 1) == constm1_rtx
- && bitwidth <= HOST_BITS_PER_WIDE_INT)
- {
- nonzero = nonzero_bits (XEXP (x, 0), mode);
- if ((((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero) == 0)
- return (nonzero == 1 || nonzero == 0 ? bitwidth
- : bitwidth - floor_log2 (nonzero) - 1);
- }
-
- num0 = num_sign_bit_copies_with_known (XEXP (x, 0), mode);
- num1 = num_sign_bit_copies_with_known (XEXP (x, 1), mode);
- result = MAX (1, MIN (num0, num1) - 1);
-
-#ifdef POINTERS_EXTEND_UNSIGNED
- /* If pointers extend signed and this is an addition or subtraction
- to a pointer in Pmode, all the bits above ptr_mode are known to be
- sign bit copies. */
- if (! POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode
- && (code == PLUS || code == MINUS)
- && GET_CODE (XEXP (x, 0)) == REG && REG_POINTER (XEXP (x, 0)))
- result = MAX ((int) (GET_MODE_BITSIZE (Pmode)
- - GET_MODE_BITSIZE (ptr_mode) + 1),
- result);
-#endif
- return result;
-
- case MULT:
- /* The number of bits of the product is the sum of the number of
- bits of both terms. However, unless one of the terms if known
- to be positive, we must allow for an additional bit since negating
- a negative number can remove one sign bit copy. */
-
- num0 = num_sign_bit_copies_with_known (XEXP (x, 0), mode);
- num1 = num_sign_bit_copies_with_known (XEXP (x, 1), mode);
-
- result = bitwidth - (bitwidth - num0) - (bitwidth - num1);
- if (result > 0
- && (bitwidth > HOST_BITS_PER_WIDE_INT
- || (((nonzero_bits (XEXP (x, 0), mode)
- & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
- && ((nonzero_bits (XEXP (x, 1), mode)
- & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))))
- result--;
-
- return MAX (1, result);
-
- case UDIV:
- /* The result must be <= the first operand. If the first operand
- has the high bit set, we know nothing about the number of sign
- bit copies. */
- if (bitwidth > HOST_BITS_PER_WIDE_INT)
- return 1;
- else if ((nonzero_bits (XEXP (x, 0), mode)
- & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
- return 1;
- else
- return num_sign_bit_copies_with_known (XEXP (x, 0), mode);
-
- case UMOD:
- /* The result must be <= the second operand. */
- return num_sign_bit_copies_with_known (XEXP (x, 1), mode);
-
- case DIV:
- /* Similar to unsigned division, except that we have to worry about
- the case where the divisor is negative, in which case we have
- to add 1. */
- result = num_sign_bit_copies_with_known (XEXP (x, 0), mode);
- if (result > 1
- && (bitwidth > HOST_BITS_PER_WIDE_INT
- || (nonzero_bits (XEXP (x, 1), mode)
- & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))
- result--;
-
- return result;
-
- case MOD:
- result = num_sign_bit_copies_with_known (XEXP (x, 1), mode);
- if (result > 1
- && (bitwidth > HOST_BITS_PER_WIDE_INT
- || (nonzero_bits (XEXP (x, 1), mode)
- & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))
- result--;
-
- return result;
-
- case ASHIFTRT:
- /* Shifts by a constant add to the number of bits equal to the
- sign bit. */
- num0 = num_sign_bit_copies_with_known (XEXP (x, 0), mode);
- if (GET_CODE (XEXP (x, 1)) == CONST_INT
- && INTVAL (XEXP (x, 1)) > 0)
- num0 = MIN ((int) bitwidth, num0 + INTVAL (XEXP (x, 1)));
-
- return num0;
-
- case ASHIFT:
- /* Left shifts destroy copies. */
- if (GET_CODE (XEXP (x, 1)) != CONST_INT
- || INTVAL (XEXP (x, 1)) < 0
- || INTVAL (XEXP (x, 1)) >= (int) bitwidth)
- return 1;
-
- num0 = num_sign_bit_copies_with_known (XEXP (x, 0), mode);
- return MAX (1, num0 - INTVAL (XEXP (x, 1)));
-
- case IF_THEN_ELSE:
- num0 = num_sign_bit_copies_with_known (XEXP (x, 1), mode);
- num1 = num_sign_bit_copies_with_known (XEXP (x, 2), mode);
- return MIN (num0, num1);
-
- case EQ: case NE: case GE: case GT: case LE: case LT:
- case UNEQ: case LTGT: case UNGE: case UNGT: case UNLE: case UNLT:
- case GEU: case GTU: case LEU: case LTU:
- case UNORDERED: case ORDERED:
- /* If the constant is negative, take its 1's complement and remask.
- Then see how many zero bits we have. */
- nonzero = STORE_FLAG_VALUE;
- if (bitwidth <= HOST_BITS_PER_WIDE_INT
- && (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
- nonzero = (~nonzero) & GET_MODE_MASK (mode);
-
- return (nonzero == 0 ? bitwidth : bitwidth - floor_log2 (nonzero) - 1);
- break;
-
- default:
- break;
- }
-
- /* If we haven't been able to figure it out by one of the above rules,
- see if some of the high-order bits are known to be zero. If so,
- count those bits and return one less than that amount. If we can't
- safely compute the mask for this mode, always return BITWIDTH. */
-
- if (bitwidth > HOST_BITS_PER_WIDE_INT)
- return 1;
-
- nonzero = nonzero_bits (x, mode);
- return (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))
- ? 1 : bitwidth - floor_log2 (nonzero) - 1);
+ if (nonzero_sign_valid && reg_stat[REGNO (x)].sign_bit_copies != 0
+ && GET_MODE_BITSIZE (GET_MODE (x)) == GET_MODE_BITSIZE (mode))
+ *result = reg_stat[REGNO (x)].sign_bit_copies;
+
+ return NULL;
}
\f
/* Return the number of "extended" bits there are in X, when interpreted
#include "except.h"
#include "target.h"
#include "params.h"
+#include "rtlhooks-def.h"
/* The basic idea of common subexpression elimination is to go
through the code, keeping a record of expressions that would
static void cse_change_cc_mode_insns (rtx, rtx, rtx);
static enum machine_mode cse_cc_succs (basic_block, rtx, rtx, bool);
\f
+
+#undef RTL_HOOKS_GEN_LOWPART
+#define RTL_HOOKS_GEN_LOWPART gen_lowpart_if_possible
+
+static const struct rtl_hooks cse_rtl_hooks = RTL_HOOKS_INITIALIZER;
+\f
/* Nonzero if X has the form (PLUS frame-pointer integer). We check for
virtual regs here because the simplify_*_operation routines are called
by integrate.c, which is called before virtual register instantiation. */
constant_pool_entries_cost = 0;
constant_pool_entries_regcost = 0;
val.path_size = 0;
- gen_lowpart = gen_lowpart_if_possible;
+ rtl_hooks = cse_rtl_hooks;
init_recog ();
init_alias_analysis ();
free (uid_cuid);
free (reg_eqv_table);
free (val.path);
- gen_lowpart = gen_lowpart_general;
+ rtl_hooks = general_rtl_hooks;
return cse_jumps_altered || recorded_label_ref;
}
at the beginning of each function. */
static GTY(()) rtx static_regno_reg_rtx[FIRST_PSEUDO_REGISTER];
-rtx (*gen_lowpart) (enum machine_mode mode, rtx x) = gen_lowpart_general;
-
/* We record floating-point CONST_DOUBLEs in each floating-point mode for
the values of 0, 1, and 2. For the integer entries and VOIDmode, we
record a copy of const[012]_rtx. */
return gen_highpart (mode, x);
}
\f
-/* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a value,
- return an rtx (MEM, SUBREG, or CONST_INT) that refers to the
- least-significant part of X.
- MODE specifies how big a part of X to return;
- it usually should not be larger than a word.
- If X is a MEM whose address is a QUEUED, the value may be so also. */
-
-rtx
-gen_lowpart_general (enum machine_mode mode, rtx x)
-{
- rtx result = gen_lowpart_common (mode, x);
-
- if (result)
- return result;
- else if (GET_CODE (x) == REG)
- {
- /* Must be a hard reg that's not valid in MODE. */
- result = gen_lowpart_common (mode, copy_to_reg (x));
- if (result == 0)
- abort ();
- return result;
- }
- else if (GET_CODE (x) == MEM)
- {
- /* The only additional case we can do is MEM. */
- int offset = 0;
-
- /* The following exposes the use of "x" to CSE. */
- if (GET_MODE_SIZE (GET_MODE (x)) <= UNITS_PER_WORD
- && SCALAR_INT_MODE_P (GET_MODE (x))
- && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
- GET_MODE_BITSIZE (GET_MODE (x)))
- && ! no_new_pseudos)
- return gen_lowpart (mode, force_reg (GET_MODE (x), x));
-
- if (WORDS_BIG_ENDIAN)
- offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
- - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
-
- if (BYTES_BIG_ENDIAN)
- /* Adjust the address so that the address-after-the-data
- is unchanged. */
- offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
- - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
-
- return adjust_address (x, mode, offset);
- }
- else if (GET_CODE (x) == ADDRESSOF)
- return gen_lowpart (mode, force_reg (GET_MODE (x), x));
- else
- abort ();
-}
-
-/* Like `gen_lowpart', but refer to the most significant part.
- This is used to access the imaginary part of a complex number. */
-
rtx
gen_highpart (enum machine_mode mode, rtx x)
{
extern bool subreg_offset_representable_p (unsigned int, enum machine_mode,
unsigned int, enum machine_mode);
extern unsigned int subreg_regno (rtx);
+extern unsigned HOST_WIDE_INT nonzero_bits (rtx, enum machine_mode);
+extern unsigned int num_sign_bit_copies (rtx, enum machine_mode);
+
/* 1 if RTX is a subreg containing a reg that is already known to be
sign- or zero-extended from the mode of the subreg to the mode of
extern rtx gen_label_rtx (void);
extern int subreg_hard_regno (rtx, int);
extern rtx gen_lowpart_common (enum machine_mode, rtx);
-extern rtx gen_lowpart_general (enum machine_mode, rtx);
-extern rtx (*gen_lowpart) (enum machine_mode mode, rtx x);
-
/* In cse.c */
extern rtx gen_lowpart_if_possible (enum machine_mode, rtx);
/* In ra.c. */
extern void reg_alloc (void);
+\f
+struct rtl_hooks
+{
+ rtx (*gen_lowpart) (enum machine_mode, rtx);
+ rtx (*reg_nonzero_bits) (rtx, enum machine_mode, rtx, enum machine_mode,
+ unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT *);
+ rtx (*reg_num_sign_bit_copies) (rtx, enum machine_mode, rtx, enum machine_mode,
+ unsigned int, unsigned int *);
+
+ /* Whenever you add entries here, make sure you adjust hosthooks-def.h. */
+};
+
+/* Each pass can provide its own. */
+extern struct rtl_hooks rtl_hooks;
+
+/* ... but then it has to restore these. */
+extern const struct rtl_hooks general_rtl_hooks;
+
+/* Keep this for the nonce. */
+#define gen_lowpart rtl_hooks.gen_lowpart
+
#endif /* ! GCC_RTL_H */
#include "basic-block.h"
#include "real.h"
#include "regs.h"
+#include "function.h"
/* Forward declarations */
static int global_reg_mentioned_p_1 (rtx *, void *);
static bool hoist_test_store (rtx, rtx, regset);
static void hoist_update_store (rtx, rtx *, rtx, rtx);
+static unsigned HOST_WIDE_INT cached_nonzero_bits (rtx, enum machine_mode,
+ rtx, enum machine_mode,
+ unsigned HOST_WIDE_INT);
+static unsigned HOST_WIDE_INT nonzero_bits1 (rtx, enum machine_mode, rtx,
+ enum machine_mode,
+ unsigned HOST_WIDE_INT);
+static unsigned int cached_num_sign_bit_copies (rtx, enum machine_mode, rtx,
+ enum machine_mode,
+ unsigned int);
+static unsigned int num_sign_bit_copies1 (rtx, enum machine_mode, rtx,
+ enum machine_mode, unsigned int);
+
/* Bit flags that specify the machine subtype we are compiling for.
Bits are tested using macros TARGET_... defined in the tm.h file
and set by `-m...' switches. Must be defined in rtlanal.c. */
{
return rtx_cost (x, MEM);
}
+\f
+
+unsigned HOST_WIDE_INT
+nonzero_bits (rtx x, enum machine_mode mode)
+{
+ return cached_nonzero_bits (x, mode, NULL_RTX, VOIDmode, 0);
+}
+
+unsigned int
+num_sign_bit_copies (rtx x, enum machine_mode mode)
+{
+ return cached_num_sign_bit_copies (x, mode, NULL_RTX, VOIDmode, 0);
+}
+
+/* The function cached_nonzero_bits is a wrapper around nonzero_bits1.
+ It avoids exponential behavior in nonzero_bits1 when X has
+ identical subexpressions on the first or the second level. */
+
+static unsigned HOST_WIDE_INT
+cached_nonzero_bits (rtx x, enum machine_mode mode, rtx known_x,
+ enum machine_mode known_mode,
+ unsigned HOST_WIDE_INT known_ret)
+{
+ if (x == known_x && mode == known_mode)
+ return known_ret;
+
+ /* Try to find identical subexpressions. If found call
+ nonzero_bits1 on X with the subexpressions as KNOWN_X and the
+ precomputed value for the subexpression as KNOWN_RET. */
+
+ if (ARITHMETIC_P (x))
+ {
+ rtx x0 = XEXP (x, 0);
+ rtx x1 = XEXP (x, 1);
+
+ /* Check the first level. */
+ if (x0 == x1)
+ return nonzero_bits1 (x, mode, x0, mode,
+ cached_nonzero_bits (x0, mode, known_x,
+ known_mode, known_ret));
+
+ /* Check the second level. */
+ if (ARITHMETIC_P (x0)
+ && (x1 == XEXP (x0, 0) || x1 == XEXP (x0, 1)))
+ return nonzero_bits1 (x, mode, x1, mode,
+ cached_nonzero_bits (x1, mode, known_x,
+ known_mode, known_ret));
+
+ if (ARITHMETIC_P (x1)
+ && (x0 == XEXP (x1, 0) || x0 == XEXP (x1, 1)))
+ return nonzero_bits1 (x, mode, x0, mode,
+ cached_nonzero_bits (x0, mode, known_x,
+ known_mode, known_ret));
+ }
+
+ return nonzero_bits1 (x, mode, known_x, known_mode, known_ret);
+}
+
+/* We let num_sign_bit_copies recur into nonzero_bits as that is useful.
+ We don't let nonzero_bits recur into num_sign_bit_copies, because that
+ is less useful. We can't allow both, because that results in exponential
+ run time recursion. There is a nullstone testcase that triggered
+ this. This macro avoids accidental uses of num_sign_bit_copies. */
+#define cached_num_sign_bit_copies sorry_i_am_preventing_exponential_behavior
+
+/* Given an expression, X, compute which bits in X can be nonzero.
+ We don't care about bits outside of those defined in MODE.
+
+ For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is
+ an arithmetic operation, we can do better. */
+
+static unsigned HOST_WIDE_INT
+nonzero_bits1 (rtx x, enum machine_mode mode, rtx known_x,
+ enum machine_mode known_mode,
+ unsigned HOST_WIDE_INT known_ret)
+{
+ unsigned HOST_WIDE_INT nonzero = GET_MODE_MASK (mode);
+ unsigned HOST_WIDE_INT inner_nz;
+ enum rtx_code code;
+ unsigned int mode_width = GET_MODE_BITSIZE (mode);
+
+ /* For floating-point values, assume all bits are needed. */
+ if (FLOAT_MODE_P (GET_MODE (x)) || FLOAT_MODE_P (mode))
+ return nonzero;
+
+ /* If X is wider than MODE, use its mode instead. */
+ if (GET_MODE_BITSIZE (GET_MODE (x)) > mode_width)
+ {
+ mode = GET_MODE (x);
+ nonzero = GET_MODE_MASK (mode);
+ mode_width = GET_MODE_BITSIZE (mode);
+ }
+
+ if (mode_width > HOST_BITS_PER_WIDE_INT)
+ /* Our only callers in this case look for single bit values. So
+ just return the mode mask. Those tests will then be false. */
+ return nonzero;
+
+#ifndef WORD_REGISTER_OPERATIONS
+ /* If MODE is wider than X, but both are a single word for both the host
+ and target machines, we can compute this from which bits of the
+ object might be nonzero in its own mode, taking into account the fact
+ that on many CISC machines, accessing an object in a wider mode
+ causes the high-order bits to become undefined. So they are
+ not known to be zero. */
+
+ if (GET_MODE (x) != VOIDmode && GET_MODE (x) != mode
+ && GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD
+ && GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT
+ && GET_MODE_BITSIZE (mode) > GET_MODE_BITSIZE (GET_MODE (x)))
+ {
+ nonzero &= cached_nonzero_bits (x, GET_MODE (x),
+ known_x, known_mode, known_ret);
+ nonzero |= GET_MODE_MASK (mode) & ~GET_MODE_MASK (GET_MODE (x));
+ return nonzero;
+ }
+#endif
+
+ code = GET_CODE (x);
+ switch (code)
+ {
+ case REG:
+#if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend)
+ /* If pointers extend unsigned and this is a pointer in Pmode, say that
+ all the bits above ptr_mode are known to be zero. */
+ if (POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode
+ && REG_POINTER (x))
+ nonzero &= GET_MODE_MASK (ptr_mode);
+#endif
+
+ /* Include declared information about alignment of pointers. */
+ /* ??? We don't properly preserve REG_POINTER changes across
+ pointer-to-integer casts, so we can't trust it except for
+ things that we know must be pointers. See execute/960116-1.c. */
+ if ((x == stack_pointer_rtx
+ || x == frame_pointer_rtx
+ || x == arg_pointer_rtx)
+ && REGNO_POINTER_ALIGN (REGNO (x)))
+ {
+ unsigned HOST_WIDE_INT alignment
+ = REGNO_POINTER_ALIGN (REGNO (x)) / BITS_PER_UNIT;
+
+#ifdef PUSH_ROUNDING
+ /* If PUSH_ROUNDING is defined, it is possible for the
+ stack to be momentarily aligned only to that amount,
+ so we pick the least alignment. */
+ if (x == stack_pointer_rtx && PUSH_ARGS)
+ alignment = MIN ((unsigned HOST_WIDE_INT) PUSH_ROUNDING (1),
+ alignment);
+#endif
+
+ nonzero &= ~(alignment - 1);
+ }
+
+ {
+ unsigned HOST_WIDE_INT nonzero_for_hook = nonzero;
+ rtx new = rtl_hooks.reg_nonzero_bits (x, mode, known_x,
+ known_mode, known_ret,
+ &nonzero_for_hook);
+
+ if (new)
+ nonzero_for_hook &= cached_nonzero_bits (new, mode, known_x,
+ known_mode, known_ret);
+
+ return nonzero_for_hook;
+ }
+
+ case CONST_INT:
+#ifdef SHORT_IMMEDIATES_SIGN_EXTEND
+ /* If X is negative in MODE, sign-extend the value. */
+ if (INTVAL (x) > 0 && mode_width < BITS_PER_WORD
+ && 0 != (INTVAL (x) & ((HOST_WIDE_INT) 1 << (mode_width - 1))))
+ return (INTVAL (x) | ((HOST_WIDE_INT) (-1) << mode_width));
+#endif
+
+ return INTVAL (x);
+
+ case MEM:
+#ifdef LOAD_EXTEND_OP
+ /* In many, if not most, RISC machines, reading a byte from memory
+ zeros the rest of the register. Noticing that fact saves a lot
+ of extra zero-extends. */
+ if (LOAD_EXTEND_OP (GET_MODE (x)) == ZERO_EXTEND)
+ nonzero &= GET_MODE_MASK (GET_MODE (x));
+#endif
+ break;
+
+ case EQ: case NE:
+ case UNEQ: case LTGT:
+ case GT: case GTU: case UNGT:
+ case LT: case LTU: case UNLT:
+ case GE: case GEU: case UNGE:
+ case LE: case LEU: case UNLE:
+ case UNORDERED: case ORDERED:
+
+ /* If this produces an integer result, we know which bits are set.
+ Code here used to clear bits outside the mode of X, but that is
+ now done above. */
+
+ if (GET_MODE_CLASS (mode) == MODE_INT
+ && mode_width <= HOST_BITS_PER_WIDE_INT)
+ nonzero = STORE_FLAG_VALUE;
+ break;
+
+ case NEG:
+#if 0
+ /* Disabled to avoid exponential mutual recursion between nonzero_bits
+ and num_sign_bit_copies. */
+ if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x))
+ == GET_MODE_BITSIZE (GET_MODE (x)))
+ nonzero = 1;
+#endif
+
+ if (GET_MODE_SIZE (GET_MODE (x)) < mode_width)
+ nonzero |= (GET_MODE_MASK (mode) & ~GET_MODE_MASK (GET_MODE (x)));
+ break;
+
+ case ABS:
+#if 0
+ /* Disabled to avoid exponential mutual recursion between nonzero_bits
+ and num_sign_bit_copies. */
+ if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x))
+ == GET_MODE_BITSIZE (GET_MODE (x)))
+ nonzero = 1;
+#endif
+ break;
+
+ case TRUNCATE:
+ nonzero &= (cached_nonzero_bits (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret)
+ & GET_MODE_MASK (mode));
+ break;
+
+ case ZERO_EXTEND:
+ nonzero &= cached_nonzero_bits (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ if (GET_MODE (XEXP (x, 0)) != VOIDmode)
+ nonzero &= GET_MODE_MASK (GET_MODE (XEXP (x, 0)));
+ break;
+
+ case SIGN_EXTEND:
+ /* If the sign bit is known clear, this is the same as ZERO_EXTEND.
+ Otherwise, show all the bits in the outer mode but not the inner
+ may be nonzero. */
+ inner_nz = cached_nonzero_bits (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ if (GET_MODE (XEXP (x, 0)) != VOIDmode)
+ {
+ inner_nz &= GET_MODE_MASK (GET_MODE (XEXP (x, 0)));
+ if (inner_nz
+ & (((HOST_WIDE_INT) 1
+ << (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - 1))))
+ inner_nz |= (GET_MODE_MASK (mode)
+ & ~GET_MODE_MASK (GET_MODE (XEXP (x, 0))));
+ }
+
+ nonzero &= inner_nz;
+ break;
+
+ case AND:
+ nonzero &= cached_nonzero_bits (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret)
+ & cached_nonzero_bits (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+ break;
+
+ case XOR: case IOR:
+ case UMIN: case UMAX: case SMIN: case SMAX:
+ {
+ unsigned HOST_WIDE_INT nonzero0 =
+ cached_nonzero_bits (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+
+ /* Don't call nonzero_bits for the second time if it cannot change
+ anything. */
+ if ((nonzero & nonzero0) != nonzero)
+ nonzero &= nonzero0
+ | cached_nonzero_bits (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+ }
+ break;
+
+ case PLUS: case MINUS:
+ case MULT:
+ case DIV: case UDIV:
+ case MOD: case UMOD:
+ /* We can apply the rules of arithmetic to compute the number of
+ high- and low-order zero bits of these operations. We start by
+ computing the width (position of the highest-order nonzero bit)
+ and the number of low-order zero bits for each value. */
+ {
+ unsigned HOST_WIDE_INT nz0 =
+ cached_nonzero_bits (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ unsigned HOST_WIDE_INT nz1 =
+ cached_nonzero_bits (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+ int sign_index = GET_MODE_BITSIZE (GET_MODE (x)) - 1;
+ int width0 = floor_log2 (nz0) + 1;
+ int width1 = floor_log2 (nz1) + 1;
+ int low0 = floor_log2 (nz0 & -nz0);
+ int low1 = floor_log2 (nz1 & -nz1);
+ HOST_WIDE_INT op0_maybe_minusp
+ = (nz0 & ((HOST_WIDE_INT) 1 << sign_index));
+ HOST_WIDE_INT op1_maybe_minusp
+ = (nz1 & ((HOST_WIDE_INT) 1 << sign_index));
+ unsigned int result_width = mode_width;
+ int result_low = 0;
+
+ switch (code)
+ {
+ case PLUS:
+ result_width = MAX (width0, width1) + 1;
+ result_low = MIN (low0, low1);
+ break;
+ case MINUS:
+ result_low = MIN (low0, low1);
+ break;
+ case MULT:
+ result_width = width0 + width1;
+ result_low = low0 + low1;
+ break;
+ case DIV:
+ if (width1 == 0)
+ break;
+ if (! op0_maybe_minusp && ! op1_maybe_minusp)
+ result_width = width0;
+ break;
+ case UDIV:
+ if (width1 == 0)
+ break;
+ result_width = width0;
+ break;
+ case MOD:
+ if (width1 == 0)
+ break;
+ if (! op0_maybe_minusp && ! op1_maybe_minusp)
+ result_width = MIN (width0, width1);
+ result_low = MIN (low0, low1);
+ break;
+ case UMOD:
+ if (width1 == 0)
+ break;
+ result_width = MIN (width0, width1);
+ result_low = MIN (low0, low1);
+ break;
+ default:
+ abort ();
+ }
+
+ if (result_width < mode_width)
+ nonzero &= ((HOST_WIDE_INT) 1 << result_width) - 1;
+
+ if (result_low > 0)
+ nonzero &= ~(((HOST_WIDE_INT) 1 << result_low) - 1);
+
+#ifdef POINTERS_EXTEND_UNSIGNED
+ /* If pointers extend unsigned and this is an addition or subtraction
+ to a pointer in Pmode, all the bits above ptr_mode are known to be
+ zero. */
+ if (POINTERS_EXTEND_UNSIGNED > 0 && GET_MODE (x) == Pmode
+ && (code == PLUS || code == MINUS)
+ && GET_CODE (XEXP (x, 0)) == REG && REG_POINTER (XEXP (x, 0)))
+ nonzero &= GET_MODE_MASK (ptr_mode);
+#endif
+ }
+ break;
+
+ case ZERO_EXTRACT:
+ if (GET_CODE (XEXP (x, 1)) == CONST_INT
+ && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT)
+ nonzero &= ((HOST_WIDE_INT) 1 << INTVAL (XEXP (x, 1))) - 1;
+ break;
+
+ case SUBREG:
+ /* If this is a SUBREG formed for a promoted variable that has
+ been zero-extended, we know that at least the high-order bits
+ are zero, though others might be too. */
+
+ if (SUBREG_PROMOTED_VAR_P (x) && SUBREG_PROMOTED_UNSIGNED_P (x) > 0)
+ nonzero = GET_MODE_MASK (GET_MODE (x))
+ & cached_nonzero_bits (SUBREG_REG (x), GET_MODE (x),
+ known_x, known_mode, known_ret);
+
+ /* If the inner mode is a single word for both the host and target
+ machines, we can compute this from which bits of the inner
+ object might be nonzero. */
+ if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) <= BITS_PER_WORD
+ && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))
+ <= HOST_BITS_PER_WIDE_INT))
+ {
+ nonzero &= cached_nonzero_bits (SUBREG_REG (x), mode,
+ known_x, known_mode, known_ret);
+
+#if defined (WORD_REGISTER_OPERATIONS) && defined (LOAD_EXTEND_OP)
+ /* If this is a typical RISC machine, we only have to worry
+ about the way loads are extended. */
+ if ((LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) == SIGN_EXTEND
+ ? (((nonzero
+ & (((unsigned HOST_WIDE_INT) 1
+ << (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) - 1))))
+ != 0))
+ : LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) != ZERO_EXTEND)
+ || GET_CODE (SUBREG_REG (x)) != MEM)
+#endif
+ {
+ /* On many CISC machines, accessing an object in a wider mode
+ causes the high-order bits to become undefined. So they are
+ not known to be zero. */
+ if (GET_MODE_SIZE (GET_MODE (x))
+ > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
+ nonzero |= (GET_MODE_MASK (GET_MODE (x))
+ & ~GET_MODE_MASK (GET_MODE (SUBREG_REG (x))));
+ }
+ }
+ break;
+
+ case ASHIFTRT:
+ case LSHIFTRT:
+ case ASHIFT:
+ case ROTATE:
+ /* The nonzero bits are in two classes: any bits within MODE
+ that aren't in GET_MODE (x) are always significant. The rest of the
+ nonzero bits are those that are significant in the operand of
+ the shift when shifted the appropriate number of bits. This
+ shows that high-order bits are cleared by the right shift and
+ low-order bits by left shifts. */
+ if (GET_CODE (XEXP (x, 1)) == CONST_INT
+ && INTVAL (XEXP (x, 1)) >= 0
+ && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT)
+ {
+ enum machine_mode inner_mode = GET_MODE (x);
+ unsigned int width = GET_MODE_BITSIZE (inner_mode);
+ int count = INTVAL (XEXP (x, 1));
+ unsigned HOST_WIDE_INT mode_mask = GET_MODE_MASK (inner_mode);
+ unsigned HOST_WIDE_INT op_nonzero =
+ cached_nonzero_bits (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ unsigned HOST_WIDE_INT inner = op_nonzero & mode_mask;
+ unsigned HOST_WIDE_INT outer = 0;
+
+ if (mode_width > width)
+ outer = (op_nonzero & nonzero & ~mode_mask);
+
+ if (code == LSHIFTRT)
+ inner >>= count;
+ else if (code == ASHIFTRT)
+ {
+ inner >>= count;
+
+ /* If the sign bit may have been nonzero before the shift, we
+ need to mark all the places it could have been copied to
+ by the shift as possibly nonzero. */
+ if (inner & ((HOST_WIDE_INT) 1 << (width - 1 - count)))
+ inner |= (((HOST_WIDE_INT) 1 << count) - 1) << (width - count);
+ }
+ else if (code == ASHIFT)
+ inner <<= count;
+ else
+ inner = ((inner << (count % width)
+ | (inner >> (width - (count % width)))) & mode_mask);
+
+ nonzero &= (outer | inner);
+ }
+ break;
+
+ case FFS:
+ case POPCOUNT:
+ /* This is at most the number of bits in the mode. */
+ nonzero = ((HOST_WIDE_INT) 2 << (floor_log2 (mode_width))) - 1;
+ break;
+
+ case CLZ:
+ /* If CLZ has a known value at zero, then the nonzero bits are
+ that value, plus the number of bits in the mode minus one. */
+ if (CLZ_DEFINED_VALUE_AT_ZERO (mode, nonzero))
+ nonzero |= ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width))) - 1;
+ else
+ nonzero = -1;
+ break;
+
+ case CTZ:
+ /* If CTZ has a known value at zero, then the nonzero bits are
+ that value, plus the number of bits in the mode minus one. */
+ if (CTZ_DEFINED_VALUE_AT_ZERO (mode, nonzero))
+ nonzero |= ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width))) - 1;
+ else
+ nonzero = -1;
+ break;
+
+ case PARITY:
+ nonzero = 1;
+ break;
+
+ case IF_THEN_ELSE:
+ {
+ unsigned HOST_WIDE_INT nonzero_true =
+ cached_nonzero_bits (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+
+ /* Don't call nonzero_bits for the second time if it cannot change
+ anything. */
+ if ((nonzero & nonzero_true) != nonzero)
+ nonzero &= nonzero_true
+ | cached_nonzero_bits (XEXP (x, 2), mode,
+ known_x, known_mode, known_ret);
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ return nonzero;
+}
+
+/* See the macro definition above. */
+#undef cached_num_sign_bit_copies
+
+\f
+/* The function cached_num_sign_bit_copies is a wrapper around
+ num_sign_bit_copies1. It avoids exponential behavior in
+ num_sign_bit_copies1 when X has identical subexpressions on the
+ first or the second level. */
+
+static unsigned int
+cached_num_sign_bit_copies (rtx x, enum machine_mode mode, rtx known_x,
+ enum machine_mode known_mode,
+ unsigned int known_ret)
+{
+ if (x == known_x && mode == known_mode)
+ return known_ret;
+
+ /* Try to find identical subexpressions. If found call
+ num_sign_bit_copies1 on X with the subexpressions as KNOWN_X and
+ the precomputed value for the subexpression as KNOWN_RET. */
+
+ if (ARITHMETIC_P (x))
+ {
+ rtx x0 = XEXP (x, 0);
+ rtx x1 = XEXP (x, 1);
+
+ /* Check the first level. */
+ if (x0 == x1)
+ return
+ num_sign_bit_copies1 (x, mode, x0, mode,
+ cached_num_sign_bit_copies (x0, mode, known_x,
+ known_mode,
+ known_ret));
+
+ /* Check the second level. */
+ if (ARITHMETIC_P (x0)
+ && (x1 == XEXP (x0, 0) || x1 == XEXP (x0, 1)))
+ return
+ num_sign_bit_copies1 (x, mode, x1, mode,
+ cached_num_sign_bit_copies (x1, mode, known_x,
+ known_mode,
+ known_ret));
+
+ if (ARITHMETIC_P (x1)
+ && (x0 == XEXP (x1, 0) || x0 == XEXP (x1, 1)))
+ return
+ num_sign_bit_copies1 (x, mode, x0, mode,
+ cached_num_sign_bit_copies (x0, mode, known_x,
+ known_mode,
+ known_ret));
+ }
+
+ return num_sign_bit_copies1 (x, mode, known_x, known_mode, known_ret);
+}
+
+/* Return the number of bits at the high-order end of X that are known to
+ be equal to the sign bit. X will be used in mode MODE; if MODE is
+ VOIDmode, X will be used in its own mode. The returned value will always
+ be between 1 and the number of bits in MODE. */
+
+static unsigned int
+num_sign_bit_copies1 (rtx x, enum machine_mode mode, rtx known_x,
+ enum machine_mode known_mode,
+ unsigned int known_ret)
+{
+ enum rtx_code code = GET_CODE (x);
+ unsigned int bitwidth = GET_MODE_BITSIZE (mode);
+ int num0, num1, result;
+ unsigned HOST_WIDE_INT nonzero;
+
+ /* If we weren't given a mode, use the mode of X. If the mode is still
+ VOIDmode, we don't know anything. Likewise if one of the modes is
+ floating-point. */
+
+ if (mode == VOIDmode)
+ mode = GET_MODE (x);
+
+ if (mode == VOIDmode || FLOAT_MODE_P (mode) || FLOAT_MODE_P (GET_MODE (x)))
+ return 1;
+
+ /* For a smaller object, just ignore the high bits. */
+ if (bitwidth < GET_MODE_BITSIZE (GET_MODE (x)))
+ {
+ num0 = cached_num_sign_bit_copies (x, GET_MODE (x),
+ known_x, known_mode, known_ret);
+ return MAX (1,
+ num0 - (int) (GET_MODE_BITSIZE (GET_MODE (x)) - bitwidth));
+ }
+
+ if (GET_MODE (x) != VOIDmode && bitwidth > GET_MODE_BITSIZE (GET_MODE (x)))
+ {
+#ifndef WORD_REGISTER_OPERATIONS
+ /* If this machine does not do all register operations on the entire
+ register and MODE is wider than the mode of X, we can say nothing
+ at all about the high-order bits. */
+ return 1;
+#else
+ /* Likewise on machines that do, if the mode of the object is smaller
+ than a word and loads of that size don't sign extend, we can say
+ nothing about the high order bits. */
+ if (GET_MODE_BITSIZE (GET_MODE (x)) < BITS_PER_WORD
+#ifdef LOAD_EXTEND_OP
+ && LOAD_EXTEND_OP (GET_MODE (x)) != SIGN_EXTEND
+#endif
+ )
+ return 1;
+#endif
+ }
+
+ switch (code)
+ {
+ case REG:
+
+#if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend)
+ /* If pointers extend signed and this is a pointer in Pmode, say that
+ all the bits above ptr_mode are known to be sign bit copies. */
+ if (! POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode && mode == Pmode
+ && REG_POINTER (x))
+ return GET_MODE_BITSIZE (Pmode) - GET_MODE_BITSIZE (ptr_mode) + 1;
+#endif
+
+ {
+ unsigned int copies_for_hook = 1, copies = 1;
+ rtx new = rtl_hooks.reg_num_sign_bit_copies (x, mode, known_x,
+ known_mode, known_ret,
+ &copies_for_hook);
+
+ if (new)
+ copies = cached_num_sign_bit_copies (new, mode, known_x,
+ known_mode, known_ret);
+
+ if (copies > 1 || copies_for_hook > 1)
+ return MAX (copies, copies_for_hook);
+
+ /* Else, use nonzero_bits to guess num_sign_bit_copies (see below). */
+ }
+ break;
+
+ case MEM:
+#ifdef LOAD_EXTEND_OP
+ /* Some RISC machines sign-extend all loads of smaller than a word. */
+ if (LOAD_EXTEND_OP (GET_MODE (x)) == SIGN_EXTEND)
+ return MAX (1, ((int) bitwidth
+ - (int) GET_MODE_BITSIZE (GET_MODE (x)) + 1));
+#endif
+ break;
+
+ case CONST_INT:
+ /* If the constant is negative, take its 1's complement and remask.
+ Then see how many zero bits we have. */
+ nonzero = INTVAL (x) & GET_MODE_MASK (mode);
+ if (bitwidth <= HOST_BITS_PER_WIDE_INT
+ && (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+ nonzero = (~nonzero) & GET_MODE_MASK (mode);
+
+ return (nonzero == 0 ? bitwidth : bitwidth - floor_log2 (nonzero) - 1);
+
+ case SUBREG:
+ /* If this is a SUBREG for a promoted object that is sign-extended
+ and we are looking at it in a wider mode, we know that at least the
+ high-order bits are known to be sign bit copies. */
+
+ if (SUBREG_PROMOTED_VAR_P (x) && ! SUBREG_PROMOTED_UNSIGNED_P (x))
+ {
+ num0 = cached_num_sign_bit_copies (SUBREG_REG (x), mode,
+ known_x, known_mode, known_ret);
+ return MAX ((int) bitwidth
+ - (int) GET_MODE_BITSIZE (GET_MODE (x)) + 1,
+ num0);
+ }
+
+ /* For a smaller object, just ignore the high bits. */
+ if (bitwidth <= GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))))
+ {
+ num0 = cached_num_sign_bit_copies (SUBREG_REG (x), VOIDmode,
+ known_x, known_mode, known_ret);
+ return MAX (1, (num0
+ - (int) (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))
+ - bitwidth)));
+ }
+
+#ifdef WORD_REGISTER_OPERATIONS
+#ifdef LOAD_EXTEND_OP
+ /* For paradoxical SUBREGs on machines where all register operations
+ affect the entire register, just look inside. Note that we are
+ passing MODE to the recursive call, so the number of sign bit copies
+ will remain relative to that mode, not the inner mode. */
+
+ /* This works only if loads sign extend. Otherwise, if we get a
+ reload for the inner part, it may be loaded from the stack, and
+ then we lose all sign bit copies that existed before the store
+ to the stack. */
+
+ if ((GET_MODE_SIZE (GET_MODE (x))
+ > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
+ && LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) == SIGN_EXTEND
+ && GET_CODE (SUBREG_REG (x)) == MEM)
+ return cached_num_sign_bit_copies (SUBREG_REG (x), mode,
+ known_x, known_mode, known_ret);
+#endif
+#endif
+ break;
+
+ case SIGN_EXTRACT:
+ if (GET_CODE (XEXP (x, 1)) == CONST_INT)
+ return MAX (1, (int) bitwidth - INTVAL (XEXP (x, 1)));
+ break;
+
+ case SIGN_EXTEND:
+ return (bitwidth - GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))
+ + cached_num_sign_bit_copies (XEXP (x, 0), VOIDmode,
+ known_x, known_mode, known_ret));
+
+ case TRUNCATE:
+ /* For a smaller object, just ignore the high bits. */
+ num0 = cached_num_sign_bit_copies (XEXP (x, 0), VOIDmode,
+ known_x, known_mode, known_ret);
+ return MAX (1, (num0 - (int) (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))
+ - bitwidth)));
+
+ case NOT:
+ return cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+
+ case ROTATE: case ROTATERT:
+ /* If we are rotating left by a number of bits less than the number
+ of sign bit copies, we can just subtract that amount from the
+ number. */
+ if (GET_CODE (XEXP (x, 1)) == CONST_INT
+ && INTVAL (XEXP (x, 1)) >= 0
+ && INTVAL (XEXP (x, 1)) < (int) bitwidth)
+ {
+ num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ return MAX (1, num0 - (code == ROTATE ? INTVAL (XEXP (x, 1))
+ : (int) bitwidth - INTVAL (XEXP (x, 1))));
+ }
+ break;
+
+ case NEG:
+ /* In general, this subtracts one sign bit copy. But if the value
+ is known to be positive, the number of sign bit copies is the
+ same as that of the input. Finally, if the input has just one bit
+ that might be nonzero, all the bits are copies of the sign bit. */
+ num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ if (bitwidth > HOST_BITS_PER_WIDE_INT)
+ return num0 > 1 ? num0 - 1 : 1;
+
+ nonzero = nonzero_bits (XEXP (x, 0), mode);
+ if (nonzero == 1)
+ return bitwidth;
+
+ if (num0 > 1
+ && (((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero))
+ num0--;
+
+ return num0;
+
+ case IOR: case AND: case XOR:
+ case SMIN: case SMAX: case UMIN: case UMAX:
+ /* Logical operations will preserve the number of sign-bit copies.
+ MIN and MAX operations always return one of the operands. */
+ num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ num1 = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+ return MIN (num0, num1);
+
+ case PLUS: case MINUS:
+ /* For addition and subtraction, we can have a 1-bit carry. However,
+ if we are subtracting 1 from a positive number, there will not
+ be such a carry. Furthermore, if the positive number is known to
+ be 0 or 1, we know the result is either -1 or 0. */
+
+ if (code == PLUS && XEXP (x, 1) == constm1_rtx
+ && bitwidth <= HOST_BITS_PER_WIDE_INT)
+ {
+ nonzero = nonzero_bits (XEXP (x, 0), mode);
+ if ((((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero) == 0)
+ return (nonzero == 1 || nonzero == 0 ? bitwidth
+ : bitwidth - floor_log2 (nonzero) - 1);
+ }
+
+ num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ num1 = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+ result = MAX (1, MIN (num0, num1) - 1);
+
+#ifdef POINTERS_EXTEND_UNSIGNED
+ /* If pointers extend signed and this is an addition or subtraction
+ to a pointer in Pmode, all the bits above ptr_mode are known to be
+ sign bit copies. */
+ if (! POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode
+ && (code == PLUS || code == MINUS)
+ && GET_CODE (XEXP (x, 0)) == REG && REG_POINTER (XEXP (x, 0)))
+ result = MAX ((int) (GET_MODE_BITSIZE (Pmode)
+ - GET_MODE_BITSIZE (ptr_mode) + 1),
+ result);
+#endif
+ return result;
+
+ case MULT:
+ /* The number of bits of the product is the sum of the number of
+ bits of both terms. However, unless one of the terms if known
+ to be positive, we must allow for an additional bit since negating
+ a negative number can remove one sign bit copy. */
+
+ num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ num1 = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+
+ result = bitwidth - (bitwidth - num0) - (bitwidth - num1);
+ if (result > 0
+ && (bitwidth > HOST_BITS_PER_WIDE_INT
+ || (((nonzero_bits (XEXP (x, 0), mode)
+ & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+ && ((nonzero_bits (XEXP (x, 1), mode)
+ & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))))
+ result--;
+
+ return MAX (1, result);
+
+ case UDIV:
+ /* The result must be <= the first operand. If the first operand
+ has the high bit set, we know nothing about the number of sign
+ bit copies. */
+ if (bitwidth > HOST_BITS_PER_WIDE_INT)
+ return 1;
+ else if ((nonzero_bits (XEXP (x, 0), mode)
+ & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+ return 1;
+ else
+ return cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+
+ case UMOD:
+ /* The result must be <= the second operand. */
+ return cached_num_sign_bit_copies (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+
+ case DIV:
+ /* Similar to unsigned division, except that we have to worry about
+ the case where the divisor is negative, in which case we have
+ to add 1. */
+ result = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ if (result > 1
+ && (bitwidth > HOST_BITS_PER_WIDE_INT
+ || (nonzero_bits (XEXP (x, 1), mode)
+ & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))
+ result--;
+
+ return result;
+
+ case MOD:
+ result = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+ if (result > 1
+ && (bitwidth > HOST_BITS_PER_WIDE_INT
+ || (nonzero_bits (XEXP (x, 1), mode)
+ & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))
+ result--;
+
+ return result;
+
+ case ASHIFTRT:
+ /* Shifts by a constant add to the number of bits equal to the
+ sign bit. */
+ num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ if (GET_CODE (XEXP (x, 1)) == CONST_INT
+ && INTVAL (XEXP (x, 1)) > 0)
+ num0 = MIN ((int) bitwidth, num0 + INTVAL (XEXP (x, 1)));
+
+ return num0;
+
+ case ASHIFT:
+ /* Left shifts destroy copies. */
+ if (GET_CODE (XEXP (x, 1)) != CONST_INT
+ || INTVAL (XEXP (x, 1)) < 0
+ || INTVAL (XEXP (x, 1)) >= (int) bitwidth)
+ return 1;
+
+ num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+ known_x, known_mode, known_ret);
+ return MAX (1, num0 - INTVAL (XEXP (x, 1)));
+
+ case IF_THEN_ELSE:
+ num0 = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+ known_x, known_mode, known_ret);
+ num1 = cached_num_sign_bit_copies (XEXP (x, 2), mode,
+ known_x, known_mode, known_ret);
+ return MIN (num0, num1);
+
+ case EQ: case NE: case GE: case GT: case LE: case LT:
+ case UNEQ: case LTGT: case UNGE: case UNGT: case UNLE: case UNLT:
+ case GEU: case GTU: case LEU: case LTU:
+ case UNORDERED: case ORDERED:
+ /* If the constant is negative, take its 1's complement and remask.
+ Then see how many zero bits we have. */
+ nonzero = STORE_FLAG_VALUE;
+ if (bitwidth <= HOST_BITS_PER_WIDE_INT
+ && (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+ nonzero = (~nonzero) & GET_MODE_MASK (mode);
+
+ return (nonzero == 0 ? bitwidth : bitwidth - floor_log2 (nonzero) - 1);
+
+ default:
+ break;
+ }
+
+ /* If we haven't been able to figure it out by one of the above rules,
+ see if some of the high-order bits are known to be zero. If so,
+ count those bits and return one less than that amount. If we can't
+ safely compute the mask for this mode, always return BITWIDTH. */
+
+ bitwidth = GET_MODE_BITSIZE (mode);
+ if (bitwidth > HOST_BITS_PER_WIDE_INT)
+ return 1;
+
+ nonzero = nonzero_bits (x, mode);
+ return nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))
+ ? 1 : bitwidth - floor_log2 (nonzero) - 1;
+}
--- /dev/null
+/* Default macros to initialize an rtl_hooks data structure.
+ Copyright 2004 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING. If not, write to
+the Free Software Foundation, 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA. */
+
+#ifndef GCC_RTL_HOOKS_DEF_H
+#define GCC_RTL_HOOKS_DEF_H
+
+#include "rtl.h"
+
+#define RTL_HOOKS_GEN_LOWPART gen_lowpart_general
+#define RTL_HOOKS_REG_NONZERO_REG_BITS reg_nonzero_bits_general
+#define RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES reg_num_sign_bit_copies_general
+
+/* The structure is defined in rtl.h. */
+#define RTL_HOOKS_INITIALIZER { \
+ RTL_HOOKS_GEN_LOWPART, \
+ RTL_HOOKS_REG_NONZERO_REG_BITS, \
+ RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES, \
+}
+
+extern rtx gen_lowpart_general (enum machine_mode, rtx);
+extern rtx reg_nonzero_bits_general (rtx, enum machine_mode, rtx,
+ enum machine_mode,
+ unsigned HOST_WIDE_INT,
+ unsigned HOST_WIDE_INT *);
+extern rtx reg_num_sign_bit_copies_general (rtx, enum machine_mode, rtx,
+ enum machine_mode,
+ unsigned int, unsigned int *);
+
+#endif /* GCC_RTL_HOOKS_DEF_H */
--- /dev/null
+/* Generic hooks for the RTL middle-end.
+ Copyright (C) 2004 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING. If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "rtlhooks-def.h"
+#include "expr.h"
+\f
+
+/* For speed, we will copy the RTX hooks struct member-by-member
+ instead of doing indirect calls. For these reason, we initialize
+ *two* struct rtl_hooks globals: rtl_hooks is the one that is used
+ to actually call the hooks, while general_rtl_hooks is used
+ to restore the hooks by passes that modify them. */
+
+const struct rtl_hooks general_rtl_hooks = RTL_HOOKS_INITIALIZER;
+struct rtl_hooks rtl_hooks = RTL_HOOKS_INITIALIZER;
+
+rtx
+gen_lowpart_general (enum machine_mode mode, rtx x)
+{
+ rtx result = gen_lowpart_common (mode, x);
+
+ if (result)
+ return result;
+ else if (GET_CODE (x) == REG)
+ {
+ /* Must be a hard reg that's not valid in MODE. */
+ result = gen_lowpart_common (mode, copy_to_reg (x));
+ if (result == 0)
+ abort ();
+ return result;
+ }
+ else if (GET_CODE (x) == MEM)
+ {
+ /* The only additional case we can do is MEM. */
+ int offset = 0;
+
+ /* The following exposes the use of "x" to CSE. */
+ if (GET_MODE_SIZE (GET_MODE (x)) <= UNITS_PER_WORD
+ && SCALAR_INT_MODE_P (GET_MODE (x))
+ && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
+ GET_MODE_BITSIZE (GET_MODE (x)))
+ && ! no_new_pseudos)
+ return gen_lowpart_general (mode, force_reg (GET_MODE (x), x));
+
+ if (WORDS_BIG_ENDIAN)
+ offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
+ - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
+
+ if (BYTES_BIG_ENDIAN)
+ /* Adjust the address so that the address-after-the-data
+ is unchanged. */
+ offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
+ - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
+
+ return adjust_address (x, mode, offset);
+ }
+ else if (GET_CODE (x) == ADDRESSOF)
+ return gen_lowpart_general (mode, force_reg (GET_MODE (x), x));
+ else
+ abort ();
+}
+
+rtx
+reg_num_sign_bit_copies_general (rtx x ATTRIBUTE_UNUSED,
+ enum machine_mode mode ATTRIBUTE_UNUSED,
+ rtx known_x ATTRIBUTE_UNUSED,
+ enum machine_mode known_mode ATTRIBUTE_UNUSED,
+ unsigned int known_ret ATTRIBUTE_UNUSED,
+ unsigned int *result ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
+
+rtx
+reg_nonzero_bits_general (rtx x ATTRIBUTE_UNUSED,
+ enum machine_mode mode ATTRIBUTE_UNUSED,
+ rtx known_x ATTRIBUTE_UNUSED,
+ enum machine_mode known_mode ATTRIBUTE_UNUSED,
+ unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED,
+ unsigned HOST_WIDE_INT *nonzero ATTRIBUTE_UNUSED)
+{
+ return NULL;
+}
projects / gcc.git / commitdiff