re PR middle-end/50195 (Linking time error with -fast-math -O0)

2011-10-10  Richard Guenther  <rguenther@suse.de>

	PR middle-end/50195
	* fold-const.c (fold_binary_loc): Canonicalize x*x to pow (x, 2)
	only when optimizing.

	* gcc.dg/builtins-47.c: Optimize.

From-SVN: r179752

gcc/ChangeLog

+2011-10-10  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/50195
+	* fold-const.c (fold_binary_loc): Canonicalize x*x to pow (x, 2)
+	only when optimizing.
+
 2011-10-10  Nick Clifton  <nickc@redhat.com>
 
 	PR middle-end/49801

gcc/fold-const.c

@@ -10693,9 +10693,9 @@ fold_binary_loc (location_t loc,
 		    }
 		}
 
-	      /* Optimize x*x as pow(x,2.0), which is expanded as x*x.  */
+	      /* Canonicalize x*x as pow(x,2.0), which is expanded as x*x.  */
 	      if (!in_gimple_form
-		  && optimize_function_for_speed_p (cfun)
+		  && optimize
 		  && operand_equal_p (arg0, arg1, 0))
 		{
 		  tree powfn = mathfn_built_in (type, BUILT_IN_POW);

gcc/testsuite/ChangeLog

+2011-10-10  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/50195
+	* gcc.dg/builtins-47.c: Optimize.
+
 2011-10-10  Aldy Hernandez  <aldyh@redhat.com>
 
 	* lib/gcc-simulate-thread.exp: New.

gcc/testsuite/gcc.dg/builtins-47.c

 /* { dg-do run } */
-/* { dg-options "-ffast-math -fdump-tree-gimple" } */
+/* { dg-options "-O -ffast-math -fdump-tree-gimple" } */
 
 extern double sqrt (double);
 extern double pow (double, double);