#include "output.h"
#include "tm-constrs.h"
#include "builtins.h"
+#include "cfgrtl.h"
+#include "tree-pass.h"
/* This file should be included last. */
#include "target-def.h"
static void cris_file_start (void);
static void cris_init_libfuncs (void);
+static unsigned int cris_postdbr_cmpelim (void);
+
static reg_class_t cris_preferred_reload_class (rtx, reg_class_t);
static int cris_register_move_cost (machine_mode, reg_class_t, reg_class_t);
struct gcc_target targetm = TARGET_INITIALIZER;
+namespace {
+
+const pass_data pass_data_cris_postdbr_cmpelim =
+{
+ RTL_PASS, /* type */
+ "mach2", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_MACH_DEP, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0, /* todo_flags_finish */
+};
+
+class pass_cris_postdbr_cmpelim : public rtl_opt_pass
+{
+public:
+ pass_cris_postdbr_cmpelim (gcc::context *ctxt)
+ : rtl_opt_pass (pass_data_cris_postdbr_cmpelim, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ virtual unsigned int execute (function *)
+ {
+ return cris_postdbr_cmpelim ();
+ }
+
+ /* No use running this if reorg and cmpelim aren't both run. */
+ virtual bool gate (function *)
+ {
+ return
+ optimize > 0
+ && flag_delayed_branch
+ && flag_compare_elim_after_reload;
+ }
+};
+
+} // anon namespace
+
+rtl_opt_pass *
+make_pass_cris_postdbr_cmpelim (gcc::context *ctxt)
+{
+ return new pass_cris_postdbr_cmpelim (ctxt);
+}
+
+/* "Cheap version" of cmpelim, making use of the opportunities opened up
+ by reorg.
+
+ Go through the insns of a function and look at each actual compare
+ insn; considering only those that compare a register to 0. If the
+ previous CC-affecting insn sets the compared register or if a move
+ reads from it, try to change that into a CC-setting move and try to
+ have it recognized. Bail at labels or non-matching insns that
+ clobber the compared register. If successful, delete the compare.
+
+ Also, reorg isn't up to date regarding data-flow handling, so we
+ can't go beyond classic RTL scanning. */
+
+static unsigned int
+cris_postdbr_cmpelim ()
+{
+ rtx_insn *insn;
+ rtx_insn *next;
+ rtx_insn *prev_cc_setter = 0;
+ rtx_insn *prev_cc_outer = 0;
+ rtx dccr = gen_rtx_REG (CCmode, CRIS_CC0_REGNUM);
+
+ /* Now look for compares in the insn stream. */
+ for (insn = get_insns (); insn; insn = next)
+ {
+ rtx_insn *outer_insn = insn;
+ rtx pat = PATTERN (insn);
+
+ next = NEXT_INSN (outer_insn);
+
+ /* Forget previous state when we see a label; we can't track or
+ merge its state. */
+ if (LABEL_P (insn))
+ {
+ prev_cc_setter = 0;
+ continue;
+ }
+
+ if (!NONDEBUG_INSN_P (insn))
+ continue;
+
+ /* Consider filled delay slots; there might be a comparison there.
+ It's only the second insn in a sequence that is interesting. */
+ if (GET_CODE (pat) == SEQUENCE)
+ insn = as_a <rtx_insn *> XVECEXP (pat, 0, 1);
+ /* The "else" eliminates temptations to consider an insn in a
+ delay slot for elimination; it can only be a prev_cc_setter. */
+ else if (prev_cc_setter != 0 && GET_CODE (pat) == SET)
+ {
+ rtx dest = SET_DEST (pat);
+ rtx src = SET_SRC (pat);
+ rtx prev_set;
+
+ if (REG_P (dest)
+ && REGNO (dest) == CRIS_CC0_REGNUM
+ && GET_CODE (src) == COMPARE
+ && REG_P (XEXP (src, 0))
+ && XEXP (src, 1) == const0_rtx
+ && (prev_set = single_set (prev_cc_setter)) != 0)
+ {
+ /* We have a candidate, and a prev_cc_setter to inspect. */
+ rtx reg = XEXP (src, 0);
+ rtx prev_dest = SET_DEST (prev_set);
+ rtx prev_src = SET_SRC (prev_set);
+ bool src_same = rtx_equal_p (prev_src, reg);
+
+ /* If the prev_cc_setter isn't a simple SET, or if the
+ compared register is modified in prev_cc_setter without
+ being the destination, or if it's modified between
+ prev_cc_setter (equal to or contained in prev_cc_outer)
+ and this insn, then we can't use the flags result. And
+ of course, the SET_DEST of prev_cc_setter (the main
+ interest, not dccr) has to be the same register and
+ mode we're interested in - or the SET_SRC. We've
+ already checked that the compared register isn't
+ changed in-between. */
+ if (REG_P (prev_dest)
+ && ! reg_set_p (reg, prev_src)
+ && ! reg_set_between_p (reg, prev_cc_outer, outer_insn)
+ && (src_same || rtx_equal_p (prev_dest, reg)))
+ {
+ machine_mode ccmode = GET_MODE (src);
+ rtx modeadjusted_dccr
+ = (ccmode == CCmode ? dccr
+ : gen_rtx_REG (CCmode, CRIS_CC0_REGNUM));
+ rtx compare
+ /* We don't need to copy_rtx pat: we're going to
+ delete that insn. */
+ = (src_same ? pat
+ : gen_rtx_SET (modeadjusted_dccr,
+ gen_rtx_COMPARE (ccmode,
+ copy_rtx (prev_src),
+ const0_rtx)));
+
+ /* Replace tentatively, the prev_set combo that is
+ ((set d s) (clobber dccr)) with
+ ((cmp s 0) (set d s)) where (cmp s 0) is the
+ compare we're looking at, and validate it or fail
+ the whole thing. First replace the ((set d s) ...)
+ with ((cmp s 0) ...)). */
+ validate_change (prev_cc_setter,
+ &XVECEXP (PATTERN (prev_cc_setter),
+ 0, 0), compare, true);
+
+ /* Then the clobber with the (set d s). */
+ validate_change (prev_cc_setter,
+ &XVECEXP (PATTERN (prev_cc_setter),
+ 0, 1), prev_set, true);
+
+ if (apply_change_group ())
+ {
+ delete_insn (insn);
+
+ /* We eliminated the compare. Then we must go to
+ the next insn: we can't consider the eliminated
+ insn for the next prev_cc_setter.
+
+ FIXME: if later insns still match, we could do
+ the delete_insn part only, for them. But, it
+ seems rare that reorg would manage to move a
+ second CC-clobber to another delay-slot,
+ leaving two identical compares (and presumably
+ users). */
+ prev_cc_setter = 0;
+ continue;
+ }
+ }
+ }
+ }
+
+ if (reg_set_p (dccr, insn))
+ {
+ rtx pat = PATTERN (insn);
+
+ prev_cc_setter = 0;
+
+ /* Make sure we can use it later on, otherwise forget it.
+ Don't look too close, we're going to pass a lot of these.
+ Just make sure the structure is that we can work with. */
+ if (GET_CODE (pat) == PARALLEL
+ && XVECLEN (pat, 0) == 2
+ && GET_CODE (XVECEXP (pat, 0, 1)) == CLOBBER)
+ {
+ prev_cc_setter = insn;
+ prev_cc_outer = outer_insn;
+ }
+ }
+ }
+
+ return 0;
+}
+
/* Helper for cris_load_multiple_op and cris_ret_movem_op. */
bool
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