From b96034f3c978a3244f04a59f208a1b25c20aea0c Mon Sep 17 00:00:00 2001
From: hubicka <hubicka@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 17 Dec 1999 11:10:58 +0000
Subject: [PATCH] * 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.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@30992 138bc75d-0d04-0410-961f-82ee72b054a4
---
gcc/ChangeLog | 8 +++++++
gcc/gcse.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 67 insertions(+), 2 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2f486f7769d0..1728e84f13e8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -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.
diff --git a/gcc/gcse.c b/gcc/gcse.c
index 701c5150955b..dc45ac1fcd0a 100644
--- a/gcc/gcse.c
+++ b/gcc/gcse.c
@@ -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 = ®_use_table[0];
for ( ; reg_use_count > 0; reg_used++, reg_use_count--)
--
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