On July 17, 2015 5:23:21 PM GMT+02:00, Marek Polacek <pola...@redhat.com> wrote:
>On Fri, Jul 17, 2015 at 02:23:50PM +0200, Richard Biener wrote:
>> >+/* Fold A - (A & B) into ~B & A. */
>> >+(simplify
>> >+ (minus (convert? @0) (convert? (bit_and:c @0 @1)))
>>
>> I think you want :s on the bit_and and its convert?
>
>Ok, I keep forgetting about this :(.
>
>> Are you sure you don't need to check for a nop conversion here?
>
>I thought I didn't need it here, and couldn't find a testcase which
>would break without tree_nop_conversion_p checks, but that doesn't mean
>much. So for extra safety I put the checks there.
>
>Bootstrapped/regtested on x86_64-linux, ok for trunk?
OK
Thanks
Richard
>2015-07-17 Marek Polacek <pola...@redhat.com>
>
> * fold-const.c (fold_binary_loc): Move A - (A & B) into ~B & A ...
> * match.pd: ... here.
>
> * gcc.dg/fold-minus-7.c: New test.
>
>diff --git gcc/fold-const.c gcc/fold-const.c
>index 93dd29d..fa321f4 100644
>--- gcc/fold-const.c
>+++ gcc/fold-const.c
>@@ -9777,30 +9777,6 @@ fold_binary_loc (location_t loc,
>
> if (! FLOAT_TYPE_P (type))
> {
>- /* Fold A - (A & B) into ~B & A. */
>- if (!TREE_SIDE_EFFECTS (arg0)
>- && TREE_CODE (arg1) == BIT_AND_EXPR)
>- {
>- if (operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0))
>- {
>- tree arg10 = fold_convert_loc (loc, type,
>- TREE_OPERAND (arg1, 0));
>- return fold_build2_loc (loc, BIT_AND_EXPR, type,
>- fold_build1_loc (loc, BIT_NOT_EXPR,
>- type, arg10),
>- fold_convert_loc (loc, type, arg0));
>- }
>- if (operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
>- {
>- tree arg11 = fold_convert_loc (loc,
>- type, TREE_OPERAND (arg1, 1));
>- return fold_build2_loc (loc, BIT_AND_EXPR, type,
>- fold_build1_loc (loc, BIT_NOT_EXPR,
>- type, arg11),
>- fold_convert_loc (loc, type, arg0));
>- }
>- }
>-
> /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
> any power of 2 minus 1. */
> if (TREE_CODE (arg0) == BIT_AND_EXPR
>diff --git gcc/match.pd gcc/match.pd
>index c335ada..700a692 100644
>--- gcc/match.pd
>+++ gcc/match.pd
>@@ -662,6 +662,12 @@ along with GCC; see the file COPYING3. If not see
> (bit_ior:c (bit_and:cs @0 (bit_not @2)) (bit_and:cs @1 @2))
> (bit_xor (bit_and (bit_xor @0 @1) @2) @0))
>
>+/* Fold A - (A & B) into ~B & A. */
>+(simplify
>+ (minus (convert? @0) (convert?:s (bit_and:cs @0 @1)))
>+ (if (tree_nop_conversion_p (type, TREE_TYPE (@0))
>+ && tree_nop_conversion_p (type, TREE_TYPE (@1)))
>+ (convert (bit_and (bit_not @1) @0))))
>
> /* Associate (p +p off1) +p off2 as (p +p (off1 + off2)). */
> (simplify
>diff --git gcc/testsuite/gcc.dg/fold-minus-7.c
>gcc/testsuite/gcc.dg/fold-minus-7.c
>index e69de29..7a49faa 100644
>--- gcc/testsuite/gcc.dg/fold-minus-7.c
>+++ gcc/testsuite/gcc.dg/fold-minus-7.c
>@@ -0,0 +1,36 @@
>+/* { dg-do compile } */
>+/* { dg-options "-O -fdump-tree-cddce1" } */
>+
>+int
>+f1 (int a, int b)
>+{
>+ int tem = a & b;
>+ return a - tem;
>+}
>+
>+int
>+f2 (int a, int b)
>+{
>+ int tem = b & a;
>+ return a - tem;
>+}
>+
>+int
>+f3 (unsigned int a, int b)
>+{
>+ return a - (a & b);
>+}
>+
>+int
>+f4 (int a, unsigned int b)
>+{
>+ return a - (a & b);
>+}
>+
>+int
>+f5 (int a, int b)
>+{
>+ return a - (unsigned) (b & a);
>+}
>+
>+/* { dg-final { scan-tree-dump-not " - " "cddce1" } } */
>
> Marek
