===================================================================
@@ -1772,6 +1772,29 @@ defcodefor_name (tree name, enum tree_co
/* Ignore arg3 currently. */
}
+/* Return true if a conversion of an operand from type FROM to type TO
+ should be applied after performing the operation instead. */
+
+static bool
+hoist_conversion_for_bitop_p (tree to, tree from)
+{
+ /* That's a good idea if the conversion widens the operand, thus
+ after hoisting the conversion the operation will be narrower. */
+ if (TYPE_PRECISION (from) < TYPE_PRECISION (to))
+ return true;
+
+ /* It's also a good idea if the conversion is to a non-integer mode. */
+ if (GET_MODE_CLASS (TYPE_MODE (to)) != MODE_INT)
+ return true;
+
+ /* Or if the precision of TO is not the same as the precision
+ of its mode. */
+ if (TYPE_PRECISION (to) != GET_MODE_PRECISION (TYPE_MODE (to)))
+ return true;
+
+ return false;
+}
+
/* Simplify bitwise binary operations.
Return true if a transformation applied, otherwise return false. */
@@ -1789,9 +1812,11 @@ simplify_bitwise_binary (gimple_stmt_ite
defcodefor_name (arg1, &def1_code, &def1_arg1, &def1_arg2);
defcodefor_name (arg2, &def2_code, &def2_arg1, &def2_arg2);
- /* Try to fold (type) X op CST -> (type) (X op ((type-x) CST)). */
+ /* Try to fold (type) X op CST -> (type) (X op ((type-x) CST))
+ when profitable. */
if (TREE_CODE (arg2) == INTEGER_CST
&& CONVERT_EXPR_CODE_P (def1_code)
+ && hoist_conversion_for_bitop_p (TREE_TYPE (arg1), TREE_TYPE (def1_arg1))
&& INTEGRAL_TYPE_P (TREE_TYPE (def1_arg1))
&& int_fits_type_p (arg2, TREE_TYPE (def1_arg1)))
{
@@ -1816,15 +1841,7 @@ simplify_bitwise_binary (gimple_stmt_ite
if (CONVERT_EXPR_CODE_P (def1_code)
&& CONVERT_EXPR_CODE_P (def2_code)
&& types_compatible_p (TREE_TYPE (def1_arg1), TREE_TYPE (def2_arg1))
- /* Make sure that the conversion widens the operands, or has same
- precision, or that it changes the operation to a bitfield
- precision. */
- && ((TYPE_PRECISION (TREE_TYPE (def1_arg1))
- <= TYPE_PRECISION (TREE_TYPE (arg1)))
- || (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (arg1)))
- != MODE_INT)
- || (TYPE_PRECISION (TREE_TYPE (arg1))
- != GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (arg1))))))
+ && hoist_conversion_for_bitop_p (TREE_TYPE (arg1), TREE_TYPE (def1_arg1)))
{
gimple newop;
tree tem = make_ssa_name (TREE_TYPE (def1_arg1), NULL);
===================================================================
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-cddce1" } */
+
+void bar (void);
+unsigned short
+foo (unsigned char x, unsigned short y)
+{
+ unsigned char t = (unsigned char)((x & 1) ^ ((unsigned char)y & 1));
+ if (t == 1)
+ bar ();
+ return y;
+}
+
+/* We should have combined this to require only one bitwise and
+ as in (x ^ (char) y) & 1. */
+
+/* { dg-final { scan-tree-dump-times " & " 1 "cddce1" } } */
+/* { dg-final { cleanup-tree-dump "cddce1" } } */