match.pd: Three new patterns

[Richard Biener]

On Fri, 19 Jun 2015, Marek Polacek wrote:

> On Thu, Jun 18, 2015 at 05:41:18PM +0200, Marek Polacek wrote:
> > > Again for symmetry, it seems like this comes with
> > > x + y - (x | y) -> x & y
> > > x + y - (x & y) -> x | y
> > > which seem fine when overflow is undefined or wraps, but not if for instance
> > > it saturates.
> > 
> > I'll leave this as a follow-up.
> 
> ...here.
> 
> Bootstrapped/regtested on x86_64-linux, ok for trunk?
> 
> 2015-06-19  Marek Polacek  <polacek@redhat.com>
> 
> 	* match.pd (x + y - (x | y) -> x & y,

) missing

> 	(x + y) - (x & y) -> x | y): New patterns.
> 
> 	* gcc.dg/fold-minus-4.c: New test.
> 	* gcc.dg/fold-minus-5.c: New test.
> 
> diff --git gcc/match.pd gcc/match.pd
> index badb80a..61ff710 100644
> --- gcc/match.pd
> +++ gcc/match.pd
> @@ -343,6 +343,18 @@ along with GCC; see the file COPYING3.  If not see
>   (plus:c (bit_and @0 @1) (bit_ior @0 @1))
>   (plus @0 @1))
>  
> +/* x + y - (x | y) -> x & y */

Please wrap x + y in () here as well.

Ok with that changes.

Thanks,
Richard.

> +(simplify
> + (minus (plus @0 @1) (bit_ior @0 @1))
> + (if (!TYPE_OVERFLOW_SANITIZED (type) && !TYPE_SATURATING (type))
> +  (bit_and @0 @1)))
> +
> +/* (x + y) - (x & y) -> x | y */
> +(simplify
> + (minus (plus @0 @1) (bit_and @0 @1))
> + (if (!TYPE_OVERFLOW_SANITIZED (type) && !TYPE_SATURATING (type))
> +  (bit_ior @0 @1)))
> +
>  /* (x | y) - (x ^ y) -> x & y */
>  (simplify
>   (minus (bit_ior @0 @1) (bit_xor @0 @1))
> diff --git gcc/testsuite/gcc.dg/fold-minus-4.c gcc/testsuite/gcc.dg/fold-minus-4.c
> index e69de29..2d76b4f 100644
> --- gcc/testsuite/gcc.dg/fold-minus-4.c
> +++ gcc/testsuite/gcc.dg/fold-minus-4.c
> @@ -0,0 +1,37 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O -fdump-tree-cddce1" } */
> +
> +int
> +fn1 (int a, int b)
> +{
> +  int tem1 = a + b;
> +  int tem2 = a & b;
> +  return tem1 - tem2;
> +}
> +
> +int
> +fn2 (int a, int b)
> +{
> +  int tem1 = b + a;
> +  int tem2 = a & b;
> +  return tem1 - tem2;
> +}
> +
> +int
> +fn3 (int a, int b)
> +{
> +  int tem1 = a + b;
> +  int tem2 = b & a;
> +  return tem1 - tem2;
> +}
> +
> +int
> +fn4 (int a, int b)
> +{
> +  int tem1 = b + a;
> +  int tem2 = b & a;
> +  return tem1 - tem2;
> +}
> +
> +/* { dg-final { scan-tree-dump-not " & " "cddce1" } } */
> +/* { dg-final { scan-tree-dump-not " \\+ " "cddce1" } } */
> diff --git gcc/testsuite/gcc.dg/fold-minus-5.c gcc/testsuite/gcc.dg/fold-minus-5.c
> index e69de29..a31e1cc 100644
> --- gcc/testsuite/gcc.dg/fold-minus-5.c
> +++ gcc/testsuite/gcc.dg/fold-minus-5.c
> @@ -0,0 +1,37 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O -fdump-tree-cddce1" } */
> +
> +int
> +fn1 (int a, int b)
> +{
> +  int tem1 = a + b;
> +  int tem2 = a | b;
> +  return tem1 - tem2;
> +}
> +
> +int
> +fn2 (int a, int b)
> +{
> +  int tem1 = b + a;
> +  int tem2 = a | b;
> +  return tem1 - tem2;
> +}
> +
> +int
> +fn3 (int a, int b)
> +{
> +  int tem1 = a + b;
> +  int tem2 = b | a;
> +  return tem1 - tem2;
> +}
> +
> +int
> +fn4 (int a, int b)
> +{
> +  int tem1 = b + a;
> +  int tem2 = b | a;
> +  return tem1 - tem2;
> +}
> +
> +/* { dg-final { scan-tree-dump-not " \\+ " "cddce1" } } */
> +/* { dg-final { scan-tree-dump-not " \\| " "cddce1" } } */
> 
> 	Marek
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Dilip Upmanyu, Graham Norton, HRB 21284 (AG Nuernberg)