From: Jakub Jelinek <jakub@redhat.com>
Date: Sat, 29 Apr 2017 16:18:11 +0000 (+0200)
Subject: re PR rtl-optimization/80491 (Compiler regression for long-add case.)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=cc3a5b33bae232329f4d02a3a8e391623ceeb5c0;p=gcc.git

re PR rtl-optimization/80491 (Compiler regression for long-add case.)

	PR rtl-optimization/80491
	* ifcvt.c (noce_process_if_block): When looking for x setter
	with missing else_bb, don't check only the insn right before
	cond_earliest, but look for the last insn that x is modified in
	within the same bb.

From-SVN: r247410
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9a9d192d01a..bb380b325a6 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2017-04-29  Jakub Jelinek  <jakub@redhat.com>
 
+	PR rtl-optimization/80491
+	* ifcvt.c (noce_process_if_block): When looking for x setter
+	with missing else_bb, don't check only the insn right before
+	cond_earliest, but look for the last insn that x is modified in
+	within the same bb.
+
 	PR rtl-optimization/80491
 	* alias.c (memory_modified_in_insn_p): Return true for CALL_INSNs.
 
diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index e51ccab26b2..75458589468 100644
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -3440,7 +3440,14 @@ noce_process_if_block (struct noce_if_info *if_info)
     }
   else
     {
-      insn_b = prev_nonnote_nondebug_insn (if_info->cond_earliest);
+      insn_b = if_info->cond_earliest;
+      do
+	insn_b = prev_nonnote_nondebug_insn (insn_b);
+      while (insn_b
+	     && (BLOCK_FOR_INSN (insn_b)
+		 == BLOCK_FOR_INSN (if_info->cond_earliest))
+	     && !modified_in_p (x, insn_b));
+
       /* We're going to be moving the evaluation of B down from above
 	 COND_EARLIEST to JUMP.  Make sure the relevant data is still
 	 intact.  */