On Wed, 4 Dec 2019, Jakub Jelinek wrote:
> Hi!
>
> The following optimizations also can't handle nop conversions between the
> inner and outer addition/subtraction, and even -fwrapv doesn't help there,
> only simplify-rtx.c is able to do something about those.
>
> Implemented thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
> ok for trunk?
KO.
Richard.
> 2019-12-04 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/92734
> * match.pd ((A +- B) - A -> +- B, (A +- B) -+ B -> A,
> A - (A +- B) -> -+ B, A +- (B -+ A) -> +- B): Handle nop_convert.
>
> * gcc.dg/tree-ssa/pr92734-2.c: New test.
>
> --- gcc/match.pd.jj 2019-12-03 10:20:00.244913801 +0100
> +++ gcc/match.pd 2019-12-03 13:36:01.084435697 +0100
> @@ -2159,20 +2159,26 @@ (define_operator_list COND_TERNARY
> /* A - (A +- B) -> -+ B */
> /* A +- (B -+ A) -> +- B */
> (simplify
> - (minus (plus:c @0 @1) @0)
> - @1)
> + (minus (nop_convert (plus:c (nop_convert @0) @1)) @0)
> + (view_convert @1))
> (simplify
> - (minus (minus @0 @1) @0)
> - (negate @1))
> + (minus (nop_convert (minus (nop_convert @0) @1)) @0)
> + (if (!ANY_INTEGRAL_TYPE_P (type)
> + || TYPE_OVERFLOW_WRAPS (type))
> + (negate (view_convert @1))
> + (view_convert (negate @1))))
> (simplify
> - (plus:c (minus @0 @1) @1)
> - @0)
> + (plus:c (nop_convert (minus @0 (nop_convert @1))) @1)
> + (view_convert @0))
> (simplify
> - (minus @0 (plus:c @0 @1))
> - (negate @1))
> + (minus @0 (nop_convert (plus:c (nop_convert @0) @1)))
> + (if (!ANY_INTEGRAL_TYPE_P (type)
> + || TYPE_OVERFLOW_WRAPS (type))
> + (negate (view_convert @1))
> + (view_convert (negate @1))))
> (simplify
> - (minus @0 (minus @0 @1))
> - @1)
> + (minus @0 (nop_convert (minus (nop_convert @0) @1)))
> + (view_convert @1))
> /* (A +- B) + (C - A) -> C +- B */
> /* (A + B) - (A - C) -> B + C */
> /* More cases are handled with comparisons. */
> --- gcc/testsuite/gcc.dg/tree-ssa/pr92734-2.c.jj 2019-12-03
> 13:56:05.036800119 +0100
> +++ gcc/testsuite/gcc.dg/tree-ssa/pr92734-2.c 2019-12-03 13:55:43.035140773
> +0100
> @@ -0,0 +1,76 @@
> +/* PR tree-optimization/92734 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +/* Verify there are no binary additions or subtractions left. There can
> + be just casts and negations. */
> +/* { dg-final { scan-tree-dump-not " \[+-] " "optimized" } } */
> +
> +int
> +f1 (int x, unsigned y)
> +{
> + int a = x + y;
> + return a - x;
> +}
> +
> +unsigned
> +f2 (unsigned x, int y)
> +{
> + unsigned a = (int) x + y;
> + return a - x;
> +}
> +
> +int
> +f3 (int x, unsigned y)
> +{
> + int a = x - y;
> + return a - x;
> +}
> +
> +unsigned
> +f4 (unsigned x, int y)
> +{
> + unsigned a = (int) x - y;
> + return a - x;
> +}
> +
> +int
> +f5 (unsigned x, int y)
> +{
> + int a = x - y;
> + return a + y;
> +}
> +
> +unsigned
> +f6 (int x, unsigned y)
> +{
> + unsigned a = x - (int) y;
> + return a + y;
> +}
> +
> +int
> +f7 (int x, unsigned y)
> +{
> + int a = x + y;
> + return x - a;
> +}
> +
> +unsigned
> +f8 (unsigned x, int y)
> +{
> + unsigned a = (int) x + y;
> + return x - a;
> +}
> +
> +int
> +f9 (int x, unsigned y)
> +{
> + int a = x - y;
> + return x - a;
> +}
> +
> +unsigned
> +f10 (unsigned x, int y)
> +{
> + unsigned a = (int) x - y;
> + return x - a;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
