re PR tree-optimization/70777 (x*x pessimised to pow(x,2) with -Og -ffast-math)

2016-04-28  Richard Biener  <rguenther@suse.de>

	PR middle-end/70777
	* fold-const.c (fold_binary_loc): Remove x*x to pow(x,2.0)
	canonicalization.

From-SVN: r235545

gcc/ChangeLog

+2016-04-28  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/70777
+	* fold-const.c (fold_binary_loc): Remove x*x to pow(x,2.0)
+	canonicalization.
+
 2016-04-28  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	* common/config/sh/sh-common.c: Remove SH5 support.

gcc/fold-const.c

@@ -10033,24 +10033,6 @@ fold_binary_loc (location_t loc,
 	      && TREE_CODE (arg1) == CONJ_EXPR
 	      && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
 	    return fold_mult_zconjz (loc, type, arg0);
-
-	  if (flag_unsafe_math_optimizations)
-	    {
-
-	      /* Canonicalize x*x as pow(x,2.0), which is expanded as x*x.  */
-	      if (!in_gimple_form
-		  && optimize
-		  && operand_equal_p (arg0, arg1, 0))
-		{
-		  tree powfn = mathfn_built_in (type, BUILT_IN_POW);
-
-		  if (powfn)
-		    {
-		      tree arg = build_real (type, dconst2);
-		      return build_call_expr_loc (loc, powfn, 2, arg0, arg);
-		    }
-		}
-	    }
 	}
       goto associate;