diff mbox

Fix PR69556

Message ID alpine.LSU.2.11.1602011634020.31122@t29.fhfr.qr
State New
Headers show

Commit Message

Richard Biener Feb. 1, 2016, 3:34 p.m. UTC 
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

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.
diff mbox

Patch

Index: gcc/match.pd
===================================================================
--- gcc/match.pd	(revision 233033)
+++ gcc/match.pd	(working copy)
@@ -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)
Index: gcc/testsuite/gcc.dg/tree-ssa/recip-8.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/recip-8.c	(revision 0)
+++ gcc/testsuite/gcc.dg/tree-ssa/recip-8.c	(working copy)
@@ -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"  } } */