Re: [r16-5316 Regression] FAIL: g++.dg/vect/pr68762-1.cc -std=c++98 (test for excess errors) on Linux/x86_64

On Sun, 16 Nov 2025, Haochen Jiang wrote:

> On Linux/x86_64,
> 
> 3d11d69600b7c3ebf0cf8eacc6a4bc8d994710e9 is the first bad commit
> commit 3d11d69600b7c3ebf0cf8eacc6a4bc8d994710e9
> Author: Richard Biener <[email protected]>
> Date:   Fri Nov 14 13:40:50 2025 +0100
> 
>     Always analyze possible partial vector usage
> 
> caused
> 
> FAIL: g++.dg/vect/pr68762-1.cc  -std=c++17 (internal compiler error: in exact_div, at poly-int.h:2179)
> FAIL: g++.dg/vect/pr68762-1.cc  -std=c++17 (test for excess errors)
> FAIL: g++.dg/vect/pr68762-1.cc  -std=c++26 (internal compiler error: in exact_div, at poly-int.h:2179)
> FAIL: g++.dg/vect/pr68762-1.cc  -std=c++26 (test for excess errors)
> FAIL: g++.dg/vect/pr68762-1.cc  -std=c++98 (internal compiler error: in exact_div, at poly-int.h:2179)
> FAIL: g++.dg/vect/pr68762-1.cc  -std=c++98 (test for excess errors)

I filed PR122736 for this latent issue and am testing a fix.

Richard.

> with GCC configured with
> 
> ../../gcc/configure --prefix=/export/users3/haochenj/src/gcc-bisect/master/master/r16-5316/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
> 
> To reproduce:
> 
> $ cd {build_dir}/gcc && make check RUNTESTFLAGS="vect.exp=g++.dg/vect/pr68762-1.cc --target_board='unix{-m32\ -march=cascadelake}'"
> $ cd {build_dir}/gcc && make check RUNTESTFLAGS="vect.exp=g++.dg/vect/pr68762-1.cc --target_board='unix{-m64\ -march=cascadelake}'"
> 
> (Please directly reply to this email for question about this report.)
> (If you met problems with cascadelake related, disabling AVX512F in command line might save that.)
> (However, please make sure that there is no potential problems with AVX512.)
> 

-- 
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)