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