(fold...

(fold, case EQ_EXPR, NE_EXPR): If COMPLEX_TYPE and at least one arg is
a COMPLEX_EXPR, split into a logical operation on the real and
imaginary parts.

From-SVN: r6313

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 6821c06..6424737 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -4479,6 +4479,28 @@ fold (expr)
          return t1 ? t1 : t;
        }
 
+      /* If this is a comparison of complex values and either or both
+        sizes are a COMPLEX_EXPR, it is best to split up the comparisons
+        and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR.  This
+        may prevent needless evaluations.  */
+      if ((code == EQ_EXPR || code == NE_EXPR)
+         && TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
+         && (TREE_CODE (arg0) == COMPLEX_EXPR
+             || TREE_CODE (arg1) == COMPLEX_EXPR))
+       {
+         tree subtype = TREE_TYPE (TREE_TYPE (arg0));
+         tree real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
+         tree imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
+         tree real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
+         tree imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
+
+         return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
+                              : TRUTH_ORIF_EXPR),
+                             type,
+                             fold (build (code, type, real0, real1)),
+                             fold (build (code, type, imag0, imag1))));
+       }
+
       /* From here on, the only cases we handle are when the result is
         known to be a constant.