return CONSTANT_P (x) && (GET_CODE (x) != CONST || shared_const_p (x));
}
+/* Determine whether the rtx X should be treated as a register that can
+ be propagated. Any pseudo-register is fine. */
+
+static bool
+cprop_reg_p (const_rtx x)
+{
+ return REG_P (x) && !HARD_REGISTER_P (x);
+}
+
/* Scan SET present in INSN and add an entry to the hash TABLE.
IMPLICIT is true if it's an implicit set, false otherwise. */
rtx src = SET_SRC (set);
rtx dest = SET_DEST (set);
- if (REG_P (dest)
- && ! HARD_REGISTER_P (dest)
+ if (cprop_reg_p (dest)
&& reg_available_p (dest, insn)
&& can_copy_p (GET_MODE (dest)))
{
src = XEXP (note, 0), set = gen_rtx_SET (VOIDmode, dest, src);
/* Record sets for constant/copy propagation. */
- if ((REG_P (src)
+ if ((cprop_reg_p (src)
&& src != dest
- && ! HARD_REGISTER_P (src)
&& reg_available_p (src, insn))
|| cprop_constant_p (src))
insert_set_in_table (dest, src, insn, table, implicit);
return success;
}
-/* Find a set of REGNOs that are available on entry to INSN's block. Return
- NULL no such set is found. */
+/* Find a set of REGNOs that are available on entry to INSN's block. If found,
+ SET_RET[0] will be assigned a set with a register source and SET_RET[1] a
+ set with a constant source. If not found the corresponding entry is set to
+ NULL. */
-static struct cprop_expr *
-find_avail_set (int regno, rtx_insn *insn)
+static void
+find_avail_set (int regno, rtx_insn *insn, struct cprop_expr *set_ret[2])
{
- /* SET1 contains the last set found that can be returned to the caller for
- use in a substitution. */
- struct cprop_expr *set1 = 0;
+ set_ret[0] = set_ret[1] = NULL;
/* Loops are not possible here. To get a loop we would need two sets
available at the start of the block containing INSN. i.e. we would
If the source operand changed, we may still use it for the next
iteration of this loop, but we may not use it for substitutions. */
- if (cprop_constant_p (src) || reg_not_set_p (src, insn))
- set1 = set;
+ if (cprop_constant_p (src))
+ set_ret[1] = set;
+ else if (reg_not_set_p (src, insn))
+ set_ret[0] = set;
/* If the source of the set is anything except a register, then
we have reached the end of the copy chain. */
and see if we have an available copy into SRC. */
regno = REGNO (src);
}
-
- /* SET1 holds the last set that was available and anticipatable at
- INSN. */
- return set1;
}
/* Subroutine of cprop_insn that tries to propagate constants into
int changed = 0, changed_this_round;
rtx note;
-retry:
- changed_this_round = 0;
- reg_use_count = 0;
- note_uses (&PATTERN (insn), find_used_regs, NULL);
-
- /* We may win even when propagating constants into notes. */
- note = find_reg_equal_equiv_note (insn);
- if (note)
- find_used_regs (&XEXP (note, 0), NULL);
-
- for (i = 0; i < reg_use_count; i++)
+ do
{
- rtx reg_used = reg_use_table[i];
- unsigned int regno = REGNO (reg_used);
- rtx src;
- struct cprop_expr *set;
+ changed_this_round = 0;
+ reg_use_count = 0;
+ note_uses (&PATTERN (insn), find_used_regs, NULL);
- /* If the register has already been set in this block, there's
- nothing we can do. */
- if (! reg_not_set_p (reg_used, insn))
- continue;
+ /* We may win even when propagating constants into notes. */
+ note = find_reg_equal_equiv_note (insn);
+ if (note)
+ find_used_regs (&XEXP (note, 0), NULL);
- /* Find an assignment that sets reg_used and is available
- at the start of the block. */
- set = find_avail_set (regno, insn);
- if (! set)
- continue;
+ for (i = 0; i < reg_use_count; i++)
+ {
+ rtx reg_used = reg_use_table[i];
+ unsigned int regno = REGNO (reg_used);
+ rtx src_cst = NULL, src_reg = NULL;
+ struct cprop_expr *set[2];
- src = set->src;
+ /* If the register has already been set in this block, there's
+ nothing we can do. */
+ if (! reg_not_set_p (reg_used, insn))
+ continue;
- /* Constant propagation. */
- if (cprop_constant_p (src))
- {
- if (constprop_register (reg_used, src, insn))
+ /* Find an assignment that sets reg_used and is available
+ at the start of the block. */
+ find_avail_set (regno, insn, set);
+ if (set[0])
+ src_reg = set[0]->src;
+ if (set[1])
+ src_cst = set[1]->src;
+
+ /* Constant propagation. */
+ if (src_cst && cprop_constant_p (src_cst)
+ && constprop_register (reg_used, src_cst, insn))
{
changed_this_round = changed = 1;
global_const_prop_count++;
"GLOBAL CONST-PROP: Replacing reg %d in ", regno);
fprintf (dump_file, "insn %d with constant ",
INSN_UID (insn));
- print_rtl (dump_file, src);
+ print_rtl (dump_file, src_cst);
fprintf (dump_file, "\n");
}
if (insn->deleted ())
return 1;
}
- }
- else if (REG_P (src)
- && REGNO (src) >= FIRST_PSEUDO_REGISTER
- && REGNO (src) != regno)
- {
- if (try_replace_reg (reg_used, src, insn))
+ /* Copy propagation. */
+ else if (src_reg && cprop_reg_p (src_reg)
+ && REGNO (src_reg) != regno
+ && try_replace_reg (reg_used, src_reg, insn))
{
changed_this_round = changed = 1;
global_copy_prop_count++;
fprintf (dump_file,
"GLOBAL COPY-PROP: Replacing reg %d in insn %d",
regno, INSN_UID (insn));
- fprintf (dump_file, " with reg %d\n", REGNO (src));
+ fprintf (dump_file, " with reg %d\n", REGNO (src_reg));
}
/* The original insn setting reg_used may or may not now be
and made things worse. */
}
}
-
- /* If try_replace_reg simplified the insn, the regs found
- by find_used_regs may not be valid anymore. Start over. */
- if (changed_this_round)
- goto retry;
}
+ /* If try_replace_reg simplified the insn, the regs found by find_used_regs
+ may not be valid anymore. Start over. */
+ while (changed_this_round);
if (changed && DEBUG_INSN_P (insn))
return 0;
/* Rule out USE instructions and ASM statements as we don't want to
change the hard registers mentioned. */
if (REG_P (x)
- && (REGNO (x) >= FIRST_PSEUDO_REGISTER
+ && (cprop_reg_p (x)
|| (GET_CODE (PATTERN (insn)) != USE
&& asm_noperands (PATTERN (insn)) < 0)))
{
if (cprop_constant_p (this_rtx))
newcnst = this_rtx;
- if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER
+ if (cprop_reg_p (this_rtx)
/* Don't copy propagate if it has attached REG_EQUIV note.
At this point this only function parameters should have
REG_EQUIV notes and if the argument slot is used somewhere
if (GET_CODE (cond) != EQ && GET_CODE (cond) != NE)
return false;
- /* The first operand of COND must be a pseudo-reg. */
- if (! REG_P (XEXP (cond, 0))
- || HARD_REGISTER_P (XEXP (cond, 0)))
+ /* The first operand of COND must be a register we can propagate. */
+ if (!cprop_reg_p (XEXP (cond, 0)))
return false;
/* The second operand of COND must be a suitable constant. */
projects / gcc.git / commitdiff