match.pd (copysign(x, CST) -> [-]abs (x)): New pattern.

2016-10-05  Richard Biener  <rguenther@suse.de>

	* match.pd (copysign(x, CST) -> [-]abs (x)): New pattern.

	* gcc.dg/fold-copysign-1.c: New testcase.

From-SVN: r240775

gcc/ChangeLog

 2016-10-05  Richard Biener  <rguenther@suse.de>
 
+	* match.pd (copysign(x, CST) -> [-]abs (x)): New pattern.
+
+2016-10-05  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/77842
 	* genmatch.c (parser::parse_c_expr): Handle premature EOF.
 

gcc/match.pd

@@ -452,6 +452,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (hypots @0 (copysigns @1 @2))
   (hypots @0 @1)))
 
+/* copysign(x, CST) -> [-]abs (x).  */
+(for copysigns (COPYSIGN)
+ (simplify
+  (copysigns @0 REAL_CST@1)
+  (if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (@1)))
+   (negate (abs @0))
+   (abs @0))))
+
 /* copysign(copysign(x, y), z) -> copysign(x, z).  */
 (for copysigns (COPYSIGN)
  (simplify

gcc/testsuite/ChangeLog

+2016-10-05  Richard Biener  <rguenther@suse.de>
+
+	* gcc.dg/fold-copysign-1.c: New testcase.
+
 2016-10-05  Andreas Schwab  <schwab@suse.de>
 
 	* g++.dg/pr49847-2.C: Remove.

gcc/testsuite/gcc.dg/fold-copysign-1.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-cddce1" } */
+
+double foo (double x)
+{
+  double one = 1.;
+  return __builtin_copysign (x, one);
+}
+double bar (double x)
+{
+  double minuszero = -0.;
+  return __builtin_copysign (x, minuszero);
+}
+
+/* { dg-final { scan-tree-dump-times "= -" 1 "cddce1" } } */
+/* { dg-final { scan-tree-dump-times "= ABS_EXPR" 2 "cddce1" } } */