From: Richard Biener <rguenther@suse.de>
Date: Wed, 12 Apr 2017 09:41:02 +0000 (+0000)
Subject: re PR tree-optimization/79390 (10% performance drop in SciMark2 LU after r242550)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=7f7e9dae36c8dd57ab89dae47a87903bbfefb530;p=gcc.git

re PR tree-optimization/79390 (10% performance drop in SciMark2 LU after r242550)

2017-04-12  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/79390
	* gimple-ssa-split-paths.c (is_feasible_trace): Restrict
	threading case even more.

From-SVN: r246869
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1458921cb44..d59a0e997ee 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-04-12  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/79390
+	* gimple-ssa-split-paths.c (is_feasible_trace): Restrict
+	threading case even more.
+
 2017-04-12  Segher Boessenkool  <segher@kernel.crashing.org>
 
 	PR target/80382
diff --git a/gcc/gimple-ssa-split-paths.c b/gcc/gimple-ssa-split-paths.c
index df88c76aa53..70651c5dea3 100644
--- a/gcc/gimple-ssa-split-paths.c
+++ b/gcc/gimple-ssa-split-paths.c
@@ -249,13 +249,17 @@ is_feasible_trace (basic_block bb)
 		  imm_use_iterator iter2;
 		  FOR_EACH_IMM_USE_FAST (use2_p, iter2, gimple_phi_result (stmt))
 		    {
-		      if (is_gimple_debug (USE_STMT (use2_p)))
+		      gimple *use_stmt = USE_STMT (use2_p);
+		      if (is_gimple_debug (use_stmt))
 			continue;
-		      basic_block use_bb = gimple_bb (USE_STMT (use2_p));
+		      basic_block use_bb = gimple_bb (use_stmt);
 		      if (use_bb != bb
 			  && dominated_by_p (CDI_DOMINATORS, bb, use_bb))
 			{
-			  found_useful_phi = true;
+			  if (gcond *cond = dyn_cast <gcond *> (use_stmt))
+			    if (gimple_cond_code (cond) == EQ_EXPR
+				|| gimple_cond_code (cond) == NE_EXPR)
+			      found_useful_phi = true;
 			  break;
 			}
 		    }