re PR middle-end/26717 (complex/complex gives a REAL_CST)

	PR middle-end/26717
	* fold-const.c (fold_binary) [RDIV_EXPR]: Do not optimize A / A
	to 1.0 for non-real operands. Implement A / A optimization for
	complex operands.


Co-Authored-By: Roger Sayle <roger@eyesopen.com>

From-SVN: r112379

gcc/ChangeLog

+2006-03-25  Uros Bizjak  <uros@kss-loka.si>
+	    Roger Sayle  <roger@eyesopen.com>
+
+	PR middle-end/26717
+	* fold-const.c (fold_binary) [RDIV_EXPR]: Do not optimize A / A
+	to 1.0 for non-real operands. Implement A / A optimization for
+	complex operands.
+
 2006-03-25  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* config/i386/i386.c (size_cost): Correct the comment for

gcc/fold-const.c

@@ -8902,8 +8902,10 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 	return NULL_TREE;
 
       /* Optimize A / A to 1.0 if we don't care about
-	 NaNs or Infinities.  */
-      if (! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))
+	 NaNs or Infinities.  Skip the transformation
+	 for non-real operands.  */
+      if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (arg0))
+	  && ! HONOR_NANS (TYPE_MODE (TREE_TYPE (arg0)))
 	  && ! HONOR_INFINITIES (TYPE_MODE (TREE_TYPE (arg0)))
 	  && operand_equal_p (arg0, arg1, 0))
 	{
@@ -8912,6 +8914,20 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 	  return omit_two_operands (type, r, arg0, arg1);
 	}
 
+      /* The complex version of the above A / A optimization.  */
+      if (COMPLEX_FLOAT_TYPE_P (TREE_TYPE (arg0))
+	  && operand_equal_p (arg0, arg1, 0))
+	{
+	  tree elem_type = TREE_TYPE (TREE_TYPE (arg0));
+	  if (! HONOR_NANS (TYPE_MODE (elem_type))
+	      && ! HONOR_INFINITIES (TYPE_MODE (elem_type)))
+	    {
+	      tree r = build_real (elem_type, dconst1);
+	      /* omit_two_operands will call fold_convert for us.  */
+	      return omit_two_operands (type, r, arg0, arg1);
+	    }
+	}
+
       /* (-A) / (-B) -> A / B  */
       if (TREE_CODE (arg0) == NEGATE_EXPR && negate_expr_p (arg1))
 	return fold_build2 (RDIV_EXPR, type,

gcc/testsuite/ChangeLog

+2006-03-25  Uros Bizjak  <uros@kss-loka.si>
+
+	PR middle-end/26717
+	* gcc.dg/pr26717.c: New test.
+
 2006-03-25  Roger Sayle  <roger@eyesopen.com>
 
 	* gfortran.dg/dependency_12.f90: New test case.

gcc/testsuite/gcc.dg/pr26717.c

+/* { dg-do compile } */
+/* { dg-options "-O -ffast-math" } */
+_Complex float f (_Complex float a)
+{
+  _Complex float b = a / a;
+  return b;
+}