On Wed, Jun 12, 2024 at 12:00 PM Uros Bizjak <ubiz...@gmail.com> wrote:
>
> On Wed, Jun 12, 2024 at 5:12 AM Hongyu Wang <hongyu.w...@intel.com> wrote:
> >
> > Hi,
> >
> > For CTEST, we don't have conditional AND so there's no optimization
> > opportunity to write a new ctest pattern. Emit ctest when ccmp did
> > comparison to const 0 to save bytes.
> >
> > Bootstrapped & regtested under x86-64-pc-linux-gnu.
> >
> > Ok for trunk?
> >
> > gcc/ChangeLog:
> >
> > * config/i386/i386.md (@ccmp<mode>): Use ctestcc when
> > operands[3] is const0_rtx.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * gcc.target/i386/apx-ccmp-1.c: Adjust output to scan ctest.
> > * gcc.target/i386/apx-ccmp-2.c: Adjust some condition to
> > compare with 0.
> > ---
> > gcc/config/i386/i386.md | 6 +++++-
> > gcc/testsuite/gcc.target/i386/apx-ccmp-1.c | 10 ++++++----
> > gcc/testsuite/gcc.target/i386/apx-ccmp-2.c | 4 ++--
> > 3 files changed, 13 insertions(+), 7 deletions(-)
> >
> > diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> > index a64f2ad4f5f..014d48cddd6 100644
> > --- a/gcc/config/i386/i386.md
> > +++ b/gcc/config/i386/i386.md
> > @@ -1522,7 +1522,11 @@ (define_insn "@ccmp<mode>"
> > [(match_operand:SI 4 "const_0_to_15_operand")]
> > UNSPEC_APX_DFV)))]
> > "TARGET_APX_CCMP"
> > - "ccmp%C1{<imodesuffix>}\t%G4 {%3, %2|%2, %3}"
> > + {
> > + if (operands[3] == const0_rtx && !MEM_P (operands[2]))
> > + return "ctest%C1{<imodesuffix>}\t%G4 %2, %2";
> > + return "ccmp%C1{<imodesuffix>}\t%G4 {%3, %2|%2, %3}";
> > + }
>
> This could be implemented as an alternative using "r,C" constraint as
> the first constraint for operands[2,3]. Then the register allocator
> will match the constraints for you.
Like in the attached (lightly tested) patch.
Uros.
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index a64f2ad4f5f..14d4d8cddca 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -1515,14 +1515,17 @@ (define_insn "@ccmp<mode>"
(match_operator 1 "comparison_operator"
[(reg:CC FLAGS_REG) (const_int 0)])
(compare:CC
- (minus:SWI (match_operand:SWI 2 "nonimmediate_operand" "<r>m,<r>")
- (match_operand:SWI 3 "<general_operand>" "<r><i>,<r><m>"))
+ (minus:SWI (match_operand:SWI 2 "nonimmediate_operand" "<r>,<r>m,<r>")
+ (match_operand:SWI 3 "<general_operand>"
"C,<r><i>,<r><m>"))
(const_int 0))
(unspec:SI
[(match_operand:SI 4 "const_0_to_15_operand")]
UNSPEC_APX_DFV)))]
"TARGET_APX_CCMP"
- "ccmp%C1{<imodesuffix>}\t%G4 {%3, %2|%2, %3}"
+ "@
+ ctest%C1{<imodesuffix>}\t%G4 %2, %2
+ ccmp%C1{<imodesuffix>}\t%G4 {%3, %2|%2, %3}
+ ccmp%C1{<imodesuffix>}\t%G4 {%3, %2|%2, %3}"
[(set_attr "type" "icmp")
(set_attr "mode" "<MODE>")
(set_attr "length_immediate" "1")
