RE: [r16-3760 Regression] FAIL: g++.target/i386/pr116896-1.C -std=gnu++23 scan-assembler-times \tjp\t 1 on Linux/x86_64

> From: Robin Dapp <[email protected]>
> Sent: Friday, September 12, 2025 2:53 PM
> 
> > FAIL: gcc.target/i386/pr116896.c scan-assembler-times \tjp\t 2
> > FAIL: g++.target/i386/pr116896-1.C  -std=gnu++20  scan-assembler-times
> \tjp\t 1
> > FAIL: g++.target/i386/pr116896-1.C  -std=gnu++23  scan-assembler-times
> \tjp\t 1
> > FAIL: g++.target/i386/pr116896-1.C  -std=gnu++26  scan-assembler-times
> \tjp\t 1
> >
> > with GCC configured with
> >
> > ../../gcc/configure --prefix=/export/users3/haochenj/src/gcc-
> bisect/master/master/r16-3760/usr --enable-clocale=gnu --with-system-zlib -
> -with-demangler-in-ld --with-fpmath=sse --enable-languages=c,c++,fortran --
> enable-cet --without-isl --enable-libmpx x86_64-linux --disable-bootstrap
> >
> 
> Grml, I had seen this error during testing but it didn't appear any more during
> the final round with the latest patch version.
> 
> This is the difference:
> 
> Before:
> 
> foo:
> .LFB0:
>         .cfi_startproc
>         xorl    %eax, %eax
>         vcomiss %xmm1, %xmm0
>         jp      .L2
>         seta    %al
>         sbbl    $0, %eax
>         ret
> .L2:
>         movl    $2, %eax
>         ret
> 	.cfi_endproc
> 
> After:
> 
> foo:
> .LFB0:
>         .cfi_startproc
>         xorl    %eax, %eax
>         vcomiss %xmm1, %xmm0
>         movl    $2, %edx
>         seta    %al
>         sbbl    $0, %eax
>         vucomiss        %xmm1, %xmm0
>         cmovp   %edx, %eax
>         ret
> 	.cfi_endproc
> 
> Is the "before" what we want, given the two other functions in the test are
> branchless?  I suppose so, as the if-converted sequence is pretty lengthy.
> 

I also believe that we should keep the before one. The main problem I suppose
would be the extra ucomi here. It is an even bigger problem than the conditional
jmp vs cmov originally in that PR.

Thx,
Haochen