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gcse.c (try_replace_reg): Do replacements in REG_EQUAL/REG_EQUIV notes too...

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* gcse.c (try_replace_reg): Do replacements in REG_EQUAL/REG_EQUIV
	notes too, create one when replacement failed, attempt to simplify
	resulting notes.
	(cprop_insn): Propagate even to registers mentioned only in REG_EQUAL
	or REG_EQUIV notes.

From-SVN: r30992
This commit is contained in:
Jan Hubicka 1999-12-17 11:10:58 +00:00 committed by Jan Hubicka
parent 5928cc35db
commit 833fc3ad23
2 changed files with 67 additions and 2 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
Fri Dec 17 12:08:11 MET 1999 Jan Hubicka <hubicka@freesoftr.cz>
* gcse.c (try_replace_reg): Do replacements in REG_EQUAL/REG_EQUIV
notes too, create one when replacement failed, attempt to simplify
resulting notes.
(cprop_insn): Propagate even to registers mentioned only in REG_EQUAL
or REG_EQUIV notes.
1999-12-16 Mark Mitchell <mark@codesourcery.com>
* crtstuff.c (__dso_handle): Declare.

61
gcc/gcse.c
View File

@ -3702,14 +3702,62 @@ static int
try_replace_reg (from, to, insn)
rtx from, to, insn;
{
rtx note;
rtx src;
int success;
rtx set;
note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
if (!note)
note = find_reg_note (insn, REG_EQUIV, NULL_RTX);
/* If this fails we could try to simplify the result of the
replacement and attempt to recognize the simplified insn.
But we need a general simplify_rtx that doesn't have pass
specific state variables. I'm not aware of one at the moment. */
return validate_replace_src (from, to, insn);
}
success = validate_replace_src (from, to, insn);
set = single_set (insn);
/* We've failed to do replacement. Try to add REG_EQUAL note to not loose
information. */
if (!success && !note)
{
if (!set)
return 0;
note = REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_EQUAL,
copy_rtx (SET_SRC (set)),
REG_NOTES (insn));
}
/* Always do the replacement in REQ_EQUAL and REG_EQUIV notes. Also
try to simplify them. */
if (note)
{
rtx simplified;
src = XEXP (note, 0);
replace_rtx (src, from, to);
/* Try to simplify resulting note. */
simplified = simplify_rtx (src);
if (simplified)
{
src = simplified;
XEXP (note, 0) = src;
}
/* REG_EQUAL may get simplified into register.
We don't allow that. Remove that note. This code ought
not to hapen, because previous code ought to syntetize
reg-reg move, but be on the safe side. */
else if (REG_P (src))
remove_note (insn, note);
}
return success;
}
/* Find a set of REGNO that is available on entry to INSN's block.
Returns NULL if not found. */
@ -3897,6 +3945,7 @@ cprop_insn (insn, alter_jumps)
{
struct reg_use *reg_used;
int changed = 0;
rtx note;
/* Only propagate into SETs. Note that a conditional jump is a
SET with pc_rtx as the destination. */
@ -3907,6 +3956,14 @@ cprop_insn (insn, alter_jumps)
reg_use_count = 0;
find_used_regs (PATTERN (insn));
note = find_reg_note (insn, REG_EQUIV, NULL_RTX);
if (!note)
note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
/* We may win even when propagating constants into notes. */
if (note)
find_used_regs (XEXP (note, 0));
reg_used = &reg_use_table[0];
for ( ; reg_use_count > 0; reg_used++, reg_use_count--)