[r16-1742 Regression] FAIL: 25_algorithms/inplace_merge/constrained.cc -std=gnu++26 (test for excess errors) on Linux/x86_64

[haochen.jiang via Gcc-regression]

On Linux/x86_64,

9d3467a14bbd75469f114b047590ebbffa4a9c8b is the first bad commit
commit 9d3467a14bbd75469f114b047590ebbffa4a9c8b
Author: Patrick Palka 
Date:   Fri Jun 27 13:53:26 2025 -0400

libstdc++: Directly implement ranges::inplace_merge [PR100795]

caused

FAIL: 25_algorithms/inplace_merge/constrained.cc  -std=gnu++20 (test for excess 
errors)
FAIL: 25_algorithms/inplace_merge/constrained.cc  -std=gnu++26 (test for excess 
errors)

with GCC configured with

../../gcc/configure 
--prefix=/export/users3/haochenj/src/gcc-bisect/master/master/r16-1742/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}/x86_64-linux/libstdc++-v3/testsuite && make check 
RUNTESTFLAGS="conformance.exp=25_algorithms/inplace_merge/constrained.cc 
--target_board='unix{-m64\ -march=cascadelake}'"

(Please do not reply to this email, for question about this report, contact me 
at haochen dot jiang at intel.com.)
(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.)

Regressions on master at commit r16-1778 vs commit r16-1776 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-1778 vs commit r16-1776 on Linux/x86_64
New failures:
FAIL: gcc.dg/lto/save-temps c_lto_save-temps_0.o-c_lto_save-temps_0.o link,  -O 
-flto -save-temps

New passes:

Regressions on master at commit r16-1829 vs commit r16-1778 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-1829 vs commit r16-1778 on Linux/x86_64
New failures:

New passes:
FAIL: gcc.dg/lto/save-temps c_lto_save-temps_0.o-c_lto_save-temps_0.o link,  -O 
-flto -save-temps

Regressions on master at commit r16-1835 vs commit r16-1833 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-1835 vs commit r16-1833 on Linux/x86_64
New failures:
FAIL: 30_threads/async/async.cc  -std=gnu++17 execution test

New passes:

Regressions on master at commit r16-1836 vs commit r16-1835 on Linux/x86_64

[Haochen Jiang via Gcc-regression]

Regressions on master at commit r16-1836 vs commit r16-1835 on Linux/x86_64
New failures:

New passes:
FAIL: 30_threads/async/async.cc  -std=gnu++17 execution test