File gcc13-pr101523.patch of Package gcc13

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File gcc13-pr101523.patch of Package gcc13

From 5729ffad4db78b26f0d1f658a9fd695be5970550 Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Wed, 3 Apr 2024 12:58:26 +0200
Subject: [PATCH] rtl-optimization/101523 - avoid re-combine after noop 2->2
 combination
To: gcc-patches@gcc.gnu.org

The following avoids re-walking and re-combining the instructions
between i2 and i3 when the pattern of i2 doesn't change.

PR rtl-optimization/101523
	* combine.cc (try_combine): When the pattern of i2 doesn't
	change do not re-start combining at i2 or an earlier insn which
	had links or notes added.
---
 gcc/combine.cc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/gcc/combine.cc b/gcc/combine.cc
index a4479f8d836..ff25752cac4 100644
--- a/gcc/combine.cc
+++ b/gcc/combine.cc
@@ -4186,6 +4186,10 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
       adjust_for_new_dest (i3);
     }
 
+  bool i2_unchanged = false;
+  if (rtx_equal_p (newi2pat, PATTERN (i2)))
+    i2_unchanged = true;
+
   /* We now know that we can do this combination.  Merge the insns and
      update the status of registers and LOG_LINKS.  */
 
@@ -4752,6 +4756,9 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
   combine_successes++;
   undo_commit ();
 
+  if (i2_unchanged)
+    return i3;
+
   rtx_insn *ret = newi2pat ? i2 : i3;
   if (added_links_insn && DF_INSN_LUID (added_links_insn) < DF_INSN_LUID (ret))
     ret = added_links_insn;
-- 
2.35.3

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File gcc13-pr101523.patch of Package gcc13

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