2016-07-27  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>

	PR middle-end/71078
	* match.pd (x / abs(x) -> copysign(1.0, x)): New pattern.

testsuite/
	* gcc.dg/tree-ssa/pr71078-1.c: New test-case.
	* gcc.dg/tree-ssa/pr71078-2.c: Likewise.
	* gcc.dg/tree-ssa/pr71078-3.c: Likewise.

diff --git a/gcc/match.pd b/gcc/match.pd
index 21bf617..2fd898a 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -195,6 +195,20 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
       && ! HONOR_INFINITIES (type))
   { build_minus_one_cst (type); }))
 
+/* PR71078: x / abs(x) -> copysign (1.0, x) */
+(simplify
+ (rdiv:C (convert? @0) (convert? (abs @0)))
+  (if (SCALAR_FLOAT_TYPE_P (type)
+       && ! HONOR_NANS (type)
+       && ! HONOR_INFINITIES (type))
+   (switch
+    (if (types_match (type, float_type_node))
+     (BUILT_IN_COPYSIGNF { build_one_cst (type); } (convert @0)))
+    (if (types_match (type, double_type_node))
+     (BUILT_IN_COPYSIGN { build_one_cst (type); } (convert @0)))
+    (if (types_match (type, long_double_type_node))
+     (BUILT_IN_COPYSIGNL { build_one_cst (type); } (convert @0))))))
+
 /* In IEEE floating point, x/1 is not equivalent to x for snans.  */
 (simplify
  (rdiv @0 real_onep)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr71078-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-1.c
new file mode 100644
index 0000000..6204c14
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-1.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -fdump-tree-forwprop-details" } */
+
+#include <math.h>
+
+float f1(float x)
+{
+  float t1 = fabsf (x);
+  float t2 = x / t1;
+  return t2;
+}
+ 
+double f2(double x)
+{
+  double t1 = fabs (x);
+  double t2 = x / t1;
+  return t2;
+}
+
+long double f3 (long double x)
+{
+  long double t1 = fabsl (x);
+  long double t2 = x / t1;
+  return t2;
+}
+
+/* { dg-final { scan-tree-dump "__builtin_copysignf" "forwprop1" } } */
+/* { dg-final { scan-tree-dump "__builtin_copysign" "forwprop1" } } */
+/* { dg-final { scan-tree-dump "__builtin_copysignl" "forwprop1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr71078-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-2.c
new file mode 100644
index 0000000..96485af
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-2.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -fdump-tree-forwprop-details" } */
+
+#include <math.h>
+
+float f1(float x)
+{
+  float t1 = fabsf (x);
+  float t2 = t1 / x; 
+  return t2;
+}
+ 
+double f2(double x)
+{
+  double t1 = fabs (x);
+  double t2 = t1 / x; 
+  return t2;
+}
+
+long double f3 (long double x)
+{
+  long double t1 = fabsl (x);
+  long double t2 = t1 / x; 
+  return t2;
+}
+
+/* { dg-final { scan-tree-dump "__builtin_copysignf" "forwprop1" } } */
+/* { dg-final { scan-tree-dump "__builtin_copysign" "forwprop1" } } */
+/* { dg-final { scan-tree-dump "__builtin_copysignl" "forwprop1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr71078-3.c b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-3.c
new file mode 100644
index 0000000..8780b6a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-3.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -fdump-tree-forwprop-details" } */
+
+#include <math.h>
+double f(float f)
+{
+  double t1 = fabs(f); 
+  double t2 = f / t1;
+  return t2;
+}
+
+/* { dg-final { scan-tree-dump "__builtin_copysign" "forwprop1" } } */