On Thu, Dec 1, 2022 at 7:57 PM Michael Collison <colli...@rivosinc.com> wrote:
>
> Richard,
>
> Can you submit this patch for me while I sort out git write access?
Done. I had to apply the patch manually - in future please make sure
to send patches that can be applied with git am.
Thanks,
Richard.
> On 11/18/22 07:57, Richard Biener wrote:
> > On Fri, Nov 11, 2022 at 3:28 AM Michael Collison <colli...@rivosinc.com>
> > wrote:
> >> This patches transforms ((x & 0x1) == 0) ? y : z <op> y -into
> >> (-(typeof(y))(x & 0x1) & z) <op> y, where op is a '^' or a '|'. It also
> >> transforms (cond (and (x , 0x1) != 0), (z op y), y ) into (-(and (x ,
> >> 0x1)) & z ) op y.
> >>
> >> Matching this patterns allows GCC to generate branchless code for one of
> >> the functions in coremark.
> >>
> >> Bootstrapped and tested on x86 and RISC-V. Okay?
> > OK.
> >
> > Thanks,
> > Richard.
> >
> >> Michael.
> >>
> >> 2022-11-10 Michael Collison <colli...@rivosinc.com>
> >>
> >> * match.pd ((x & 0x1) == 0) ? y : z <op> y
> >> -> (-(typeof(y))(x & 0x1) & z) <op> y.
> >>
> >> 2022-11-10 Michael Collison <colli...@rivosinc.com>
> >>
> >> * gcc.dg/tree-ssa/branchless-cond.c: New test.
> >>
> >> ---
> >>
> >> Changes in v2:
> >>
> >> - Rewrite comment to use C syntax
> >>
> >> - Guard against 1-bit types
> >>
> >> - Simplify pattern by using zero_one_valued_p
> >>
> >> gcc/match.pd | 24 +++++++++++++++++
> >> .../gcc.dg/tree-ssa/branchless-cond.c | 26 +++++++++++++++++++
> >> 2 files changed, 50 insertions(+)
> >> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c
> >>
> >> diff --git a/gcc/match.pd b/gcc/match.pd
> >> index 194ba8f5188..258531e9046 100644
> >> --- a/gcc/match.pd
> >> +++ b/gcc/match.pd
> >> @@ -3486,6 +3486,30 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> >> (cond (le @0 integer_zerop@1) (negate@2 @0) integer_zerop@1)
> >> (max @2 @1))
> >>
> >> +/* ((x & 0x1) == 0) ? y : z <op> y -> (-(typeof(y))(x & 0x1) & z) <op> y
> >> */
> >> +(for op (bit_xor bit_ior)
> >> + (simplify
> >> + (cond (eq zero_one_valued_p@0
> >> + integer_zerop)
> >> + @1
> >> + (op:c @2 @1))
> >> + (if (INTEGRAL_TYPE_P (type)
> >> + && TYPE_PRECISION (type) > 1
> >> + && (INTEGRAL_TYPE_P (TREE_TYPE (@0))))
> >> + (op (bit_and (negate (convert:type @0)) @2) @1))))
> >> +
> >> +/* ((x & 0x1) == 0) ? z <op> y : y -> (-(typeof(y))(x & 0x1) & z) <op> y
> >> */
> >> +(for op (bit_xor bit_ior)
> >> + (simplify
> >> + (cond (ne zero_one_valued_p@0
> >> + integer_zerop)
> >> + (op:c @2 @1)
> >> + @1)
> >> + (if (INTEGRAL_TYPE_P (type)
> >> + && TYPE_PRECISION (type) > 1
> >> + && (INTEGRAL_TYPE_P (TREE_TYPE (@0))))
> >> + (op (bit_and (negate (convert:type @0)) @2) @1))))
> >> +
> >> /* Simplifications of shift and rotates. */
> >>
> >> (for rotate (lrotate rrotate)
> >> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c
> >> b/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c
> >> new file mode 100644
> >> index 00000000000..68087ae6568
> >> --- /dev/null
> >> +++ b/gcc/testsuite/gcc.dg/tree-ssa/branchless-cond.c
> >> @@ -0,0 +1,26 @@
> >> +/* { dg-do compile } */
> >> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> >> +
> >> +int f1(unsigned int x, unsigned int y, unsigned int z)
> >> +{
> >> + return ((x & 1) == 0) ? y : z ^ y;
> >> +}
> >> +
> >> +int f2(unsigned int x, unsigned int y, unsigned int z)
> >> +{
> >> + return ((x & 1) != 0) ? z ^ y : y;
> >> +}
> >> +
> >> +int f3(unsigned int x, unsigned int y, unsigned int z)
> >> +{
> >> + return ((x & 1) == 0) ? y : z | y;
> >> +}
> >> +
> >> +int f4(unsigned int x, unsigned int y, unsigned int z)
> >> +{
> >> + return ((x & 1) != 0) ? z | y : y;
> >> +}
> >> +
> >> +/* { dg-final { scan-tree-dump-times " -" 4 "optimized" } } */
> >> +/* { dg-final { scan-tree-dump-times " & " 8 "optimized" } } */
> >> +/* { dg-final { scan-tree-dump-not "if" "optimized" } } */
> >> --
> >> 2.34.1
> >>
