(simplify_comparison): Can remove NOT on both operands if we swap

comparison code.

From-SVN: r6410

diff --git a/gcc/combine.c b/gcc/combine.c
index d6993672925ada5d3072fabc33541e30bbd7b10f..1737e6ec465b6b593621b412e35f2ef27bfa82e1 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -8429,7 +8429,7 @@ simplify_comparison (code, pop0, pop1)
          && GET_CODE (XEXP (XEXP (op0, 0), 0)) == SUBREG
          && GET_CODE (XEXP (XEXP (op1, 0), 0)) == SUBREG
          && (GET_MODE (SUBREG_REG (XEXP (XEXP (op0, 0), 0)))
-             == GET_MODE (SUBREG_REG (XEXP (XEXP (op0, 0), 0))))
+             == GET_MODE (SUBREG_REG (XEXP (XEXP (op1, 0), 0))))
          && GET_CODE (XEXP (op0, 1)) == CONST_INT
          && GET_CODE (XEXP (op1, 1)) == CONST_INT
          && GET_CODE (XEXP (XEXP (op0, 0), 1)) == CONST_INT
@@ -8517,12 +8517,13 @@ simplify_comparison (code, pop0, pop1)
          code = unsigned_condition (code);
        }
 
-      /* If both operands are NOT or both are NEG, we can strip off the
-        outer operation if this is just an equality comparison.  */
-      else if ((code == EQ || code == NE)
-              && ((GET_CODE (op0) == NOT && GET_CODE (op1) == NOT)
-                  || (GET_CODE (op0) == NEG && GET_CODE (op1) == NEG)))
-       op0 = XEXP (op0, 0), op1 = XEXP (op1, 0);
+      /* If both operands are NOT, we can strip off the outer operation
+        and adjust the comparison code for swapped operands; similarly for
+        NEG, except that this must be an equality comparison.  */
+      else if ((GET_CODE (op0) == NOT && GET_CODE (op1) == NOT)
+              || (GET_CODE (op0) == NEG && GET_CODE (op1) == NEG
+                  && (code == EQ || code == NE)))
+       op0 = XEXP (op0, 0), op1 = XEXP (op1, 0), code = swap_condition (code);
 
       else
        break;