On Fri, May 15, 2026 at 6:30 PM Richard Biener <[email protected]>
wrote:

> On Tue, May 12, 2026 at 7:47 PM Shivam Gupta <[email protected]>
> wrote:
> >
> > This adds the simplification of:
> >   _1 = ~x_2(D);
> >   t1_4 = _1 & y_3(D);
> >   t2_5 = x_2(D) | y_3(D);
> >   _6 = t1_4 ^ t2_5;
> >   return _6;
> >
> > to:
> >   return x_1(D);
> >
> > also for ((~x) | y) ^ (x & y) version
> >   _1 = ~x_2(D);
> >   t1_4 = _1 | y_3(D);
> >   t2_5 = x_2(D) & y_3(D);
> >   _6 = t1_4 ^ t2_5;
> >   return _6;
> > to:
> >    int _1;
> >    _1 = ~x_2(D);
> >    return _1;
> >
> > Bootstrapped and tested on aarch64-linux-gnu with
> > RUNTESTFLAGS="tree-ssa.exp".
>
> OK.
>
> Thanks,
> Richard.
>
>
Hi Richard,

Thanks for the OK.
I don't have commit access, could you please push the patch for me?

Thanks,
Shivam


> > changes since v1:
> > * v3: Change sf2/sg2 to sf/sg in test case
> > * v2:
> > - Update testcase to exercise GIMPLE folding
> > - Add additional type coverage
> > - Add vector and _Bool coverage
> > - Move code above in the file
> >
> >         PR tree-optimization/112095
> >
> > gcc/ChangeLog:
> >
> >         * match.pd: Simplify ((~x) & y) ^ (x | y)
> >         to x and ((~x) | y) ^ (x & y) to ~x.
> >
> > gcc/testsuite/ChangeLog:
> >
> >         * gcc.dg/tree-ssa/pr112095.c: New test.
> >
> > Signed-off-by: Shivam Gupta <[email protected]>
> > ---
> >  gcc/match.pd                             |   9 ++
> >  gcc/testsuite/gcc.dg/tree-ssa/pr112095.c | 127 +++++++++++++++++++++++
> >  2 files changed, 136 insertions(+)
> >  create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr112095.c
> >
> > diff --git a/gcc/match.pd b/gcc/match.pd
> > index 7b652afb43d..327598bfd63 100644
> > --- a/gcc/match.pd
> > +++ b/gcc/match.pd
> > @@ -1606,6 +1606,15 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> >        && TYPE_PRECISION (TREE_TYPE (@0)) == 1)
> >    @2))
> >
> > +/* ((~a) & b) ^ (a | b) --> a  */
> > +/* ((~a) | b) ^ (a & b) --> ~a  */
> > +(simplify
> > + (bit_xor:c (bit_ior:c @0 @1) (bit_and:c @2 @1))
> > + (with { bool wascmp; }
> > +  (if (bitwise_inverted_equal_p (@0, @2, wascmp)
> > +       && (!wascmp || element_precision (type) == 1))
> > +   @0)))
> > +
> >  /* ~(~a & b)  -->  a | ~b  */
> >  (simplify
> >   (bit_not (bit_and:cs (bit_not @0) @1))
> > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr112095.c
> b/gcc/testsuite/gcc.dg/tree-ssa/pr112095.c
> > new file mode 100644
> > index 00000000000..992d0e1f29d
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr112095.c
> > @@ -0,0 +1,127 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O -fdump-tree-optimized" } */
> > +
> > +typedef signed int s32;
> > +typedef unsigned char u8;
> > +typedef unsigned short u16;
> > +typedef unsigned int u32;
> > +typedef unsigned long u64;
> > +typedef __attribute__((vector_size(4 * sizeof (unsigned int))))
> unsigned int v4ui;
> > +
> > +s32
> > +sf (s32 a, s32 b)
> > +{
> > +  s32 t1 = (~a) & b;
> > +  s32 t2 = a | b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +s32
> > +sg (s32 a, s32 b)
> > +{
> > +  s32 t1 = (~a) | b;
> > +  s32 t2 = a & b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +u8
> > +f1 (u8 a, u8 b)
> > +{
> > +  u8 t1 = (~a) & b;
> > +  u8 t2 = a | b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +u8
> > +g1 (u8 a, u8 b)
> > +{
> > +  u8 t1 = (~a) | b;
> > +  u8 t2 = a & b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +u16
> > +f2 (u16 a, u16 b)
> > +{
> > +  u16 t1 = (~a) & b;
> > +  u16 t2 = a | b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +u16
> > +g2 (u16 a, u16 b)
> > +{
> > +  u16 t1 = (~a) | b;
> > +  u16 t2 = a & b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +u32
> > +f3 (u32 a, u32 b)
> > +{
> > +  u32 t1 = (~a) & b;
> > +  u32 t2 = a | b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +u32
> > +g3 (u32 a, u32 b)
> > +{
> > +  u32 t1 = (~a) | b;
> > +  u32 t2 = a & b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +u64
> > +f4 (u64 a, u64 b)
> > +{
> > +  u64 t1 = (~a) & b;
> > +  u64 t2 = a | b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +u64
> > +g4 (u64 a, u64 b)
> > +{
> > +  u64 t1 = (~a) | b;
> > +  u64 t2 = a & b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +_Bool
> > +bf (_Bool a, _Bool b)
> > +{
> > +  _Bool t1 = (~a) & b;
> > +  _Bool t2 = a | b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +_Bool
> > +bg (_Bool a, _Bool b)
> > +{
> > +  _Bool t1 = (~a) | b;
> > +  _Bool t2 = a & b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +v4ui
> > +vf (v4ui a, v4ui b)
> > +{
> > +  v4ui t1 = (~a) & b;
> > +  v4ui t2 = a | b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +v4ui
> > +vg (v4ui a, v4ui b)
> > +{
> > +  v4ui t1 = (~a) | b;
> > +  v4ui t2 = a & b;
> > +  return t1 ^ t2;
> > +}
> > +
> > +/* f* and vf should simplify to return a.  */
> > +/* { dg-final { scan-tree-dump-times "return a_" 6 "optimized" } } */
> > +
> > +/* g* and vg should simplify to ~a directly.  */
> > +/* { dg-final { scan-tree-dump-times "= ~a" 6 "optimized" } } */
> > --
> > 2.34.1
> >
>

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