* simplify-rtx.c (simplify_binary_operation_1, case AND): Result is

	zero if no overlap in nonzero bits between the operands.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@146738 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b0ed4ff..a48db46 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2009-04-24  Bernd Schmidt  <bernd.schmidt@analog.com>
+
+       * simplify-rtx.c (simplify_binary_operation_1, case AND): Result is
+       zero if no overlap in nonzero bits between the operands.
+
 2009-04-24  Ian Lance Taylor  <iant@google.com>
 
        * combine.c (record_value_for_reg): Change 0 to VOIDmode, twice.

diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index b8b6ad8..e2b1673 100644 (file)
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -2304,17 +2304,22 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
     case AND:
       if (trueop1 == CONST0_RTX (mode) && ! side_effects_p (op0))
        return trueop1;
-      if (GET_CODE (trueop1) == CONST_INT
-         && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)
+      if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)
        {
          HOST_WIDE_INT nzop0 = nonzero_bits (trueop0, mode);
-         HOST_WIDE_INT val1 = INTVAL (trueop1);
-         /* If we are turning off bits already known off in OP0, we need
-            not do an AND.  */
-         if ((nzop0 & ~val1) == 0)
-           return op0;
+         HOST_WIDE_INT nzop1;
+         if (GET_CODE (trueop1) == CONST_INT)
+           {
+             HOST_WIDE_INT val1 = INTVAL (trueop1);
+             /* If we are turning off bits already known off in OP0, we need
+                not do an AND.  */
+             if ((nzop0 & ~val1) == 0)
+               return op0;
+           }
+         nzop1 = nonzero_bits (trueop1, mode);
          /* If we are clearing all the nonzero bits, the result is zero.  */
-         if ((val1 & nzop0) == 0 && !side_effects_p (op0))
+         if ((nzop1 & nzop0) == 0
+             && !side_effects_p (op0) && !side_effects_p (op1))
            return CONST0_RTX (mode);
        }
       if (rtx_equal_p (trueop0, trueop1) && ! side_effects_p (op0)