From: Richard Biener <rguenther@suse.de>
Date: Mon, 1 Feb 2016 15:40:23 +0000 (+0000)
Subject: re PR tree-optimization/69556 (forwprop4/match.pd undoing work from recip)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ff86345f836c265d6bbb8d1bee5417e6f4c32ac9;p=gcc.git

re PR tree-optimization/69556 (forwprop4/match.pd undoing work from recip)

2016-02-01  Richard Biener  <rguenther@suse.de>

	PR middle-end/69556
	* match.pd: Guard (C1/X)*C2 -> (C1*C2)/X with single_use.

	* gcc.dg/tree-ssa/recip-8.c: New testcase.

From-SVN: r233040
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 15baad3a186..e17d3c54fb8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2016-02-01  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/69556
+	* match.pd: Guard (C1/X)*C2 -> (C1*C2)/X with single_use.
+
 2016-02-01  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/69574
diff --git a/gcc/match.pd b/gcc/match.pd
index 63134114bdb..491f769c1dd 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -445,8 +445,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 
 /* Fold (C1/X)*C2 into (C1*C2)/X.  */
 (simplify
- (mult (rdiv:s REAL_CST@0 @1) REAL_CST@2)
-  (if (flag_associative_math)
+ (mult (rdiv@3 REAL_CST@0 @1) REAL_CST@2)
+  (if (flag_associative_math
+       && single_use (@3))
    (with
     { tree tem = const_binop (MULT_EXPR, type, @0, @2); }
     (if (tem)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 68278d13f85..bfd6e9f6ce4 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-02-01  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/69556
+	* gcc.dg/tree-ssa/recip-8.c: New testcase.
+
 2016-02-01  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/69574
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/recip-8.c b/gcc/testsuite/gcc.dg/tree-ssa/recip-8.c
new file mode 100644
index 00000000000..f8aecc127c1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/recip-8.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -fdump-tree-optimized" } */
+
+double bar (double, double, double, double, double);
+
+double
+foo (double a)
+{
+  return bar (1.0/a, 2.0/a, 4.0/a, 8.0/a, 16.0/a);
+}
+
+/* { dg-final { scan-tree-dump-times "/" 1 "optimized"  } } */