* fold-const.c (fold <ABS_EXPR>): Re-fold the result of folding

	fabs(-x) into fabs(x).  Use tree_expr_nonnegative_p to determine
	when the ABS_EXPR (fabs or abs) is not required.
  	(tree_expr_nonnegative_p): Move the logic that sqrt and exp are
	always nonnegative from fold to here.  Additionally, cabs and fabs
	are always non-negative, and pow and atan are non-negative if
	their first argument is non-negative.

	* builtins.c (fold_builtin_cabs): New function to fold cabs{,f,l}.
	Evaluate cabs of a constant at compile-time.  Convert cabs of a
	non-complex argument into fabs.  Convert cabs(z) into
	sqrt(z.r*z.r + z.i*z.i) at the tree-level with -ffast-math or
	-funsafe-math-optimizations or -ffast-math.
	(fold_builtin): Convert BUILT_IN_FABS{,F,L} into an ABS_EXPR.
	Fold BUILT_IN_CABS{,F,L} using fold_builtin_cabs.

	* gcc.dg/builtins-2.c: Add some more tests.
	* gcc.dg/builtins-18.c: New test case.
	* gcc.dg/builtins-19.c: New test case.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@67541 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 45 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/builtins-2.c b/gcc/testsuite/gcc.dg/builtins-2.c
index ebd054f229a..895b80a2ef9 100644
--- a/gcc/testsuite/gcc.dg/builtins-2.c
+++ b/gcc/testsuite/gcc.dg/builtins-2.c
@@ -58,6 +58,21 @@ double test10(double x)
   return tan(atan(x));
 }
 
+double test11(double x)
+{
+  return fabs(fabs(x));
+}
+
+double test12(double x)
+{
+  return fabs(atan(x));
+}
+
+double test13(double x)
+{
+  return fabs(pow(2.0,x));
+}
+
 float test1f(float x)
 {
   return logf(expf(x));
@@ -108,6 +123,21 @@ float test10f(float x)
   return tanf(atanf(x));
 }
 
+floatf test11f(float x)
+{
+  return fabsf(fabsf(x));
+}
+
+floatf test12f(float x)
+{
+  return fabsf(atanf(x));
+}
+
+float test13f(float x)
+{
+  return fabsf(powf(2.0f,x));
+}
+
 long double test1l(long double x)
 {
   return logl(expl(x));
@@ -158,3 +188,18 @@ long double test10l(long double x)
   return tanl(atanl(x));
 }
 
+long double test11l(long double x)
+{
+  return fabsl(fabsl(x));
+}
+
+long double test12l(long double x)
+{
+  return fabsl(atanl(x));
+}
+
+long double test13l(long double x)
+{
+  return fabsl(powl(2.0l,x));
+}
+