https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119618
Bug ID: 119618
Summary: Python PGO vs musttail (error: cannot tail-call:
memory reference or volatile after call)
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: gcov-profile
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
Target Milestone: ---
Created attachment 60990
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=60990&action=edit
ceval.i.xz
```
$ gcc -c -fno-strict-overflow -Wsign-compare -DNDEBUG -g -O3 -Wall -std=c11
-Wextra -Wno-unused-parameter -Wno-missing-field-initializers
-Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden
-I./Include/internal -I./Include/internal/mimalloc -I. -I./Include
-DPy_BUILD_CORE -o Python/ceval.o Python/ceval.c -save-temps -fprofile-generate
-Wfatal-errors -Wno-attributes
In file included from Python/ceval.c:955:
Python/generated_cases.c.h:11991:50: warning: ‘_TAIL_CALL_pop_3_error’ defined
but not used [-Wunused-function]
11991 | LABEL(pop_3_error)
| ^
Python/generated_cases.c.h:11985:50: warning: ‘_TAIL_CALL_pop_4_error’ defined
but not used [-Wunused-function]
11985 | LABEL(pop_4_error)
| ^
In function ‘_TAIL_CALL_pop_2_error’,
inlined from ‘_TAIL_CALL_BINARY_OP_ADD_FLOAT’ at
Python/generated_cases.c.h:134:53:
Python/generated_cases.c.h:12000:45: error: cannot tail-call: memory reference
or volatile after call
12000 | JUMP_TO_LABEL(error);
| ^
compilation terminated due to -Wfatal-errors.
```
---
```
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/15/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-pc-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/configure
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/15
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/15/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/15
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/15/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/15/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/15/include/g++-v15
--disable-silent-rules --disable-dependency-tracking
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/15/python
--enable-libphobos --enable-objc-gc
--enable-languages=c,c++,d,go,objc,obj-c++,fortran,ada,cobol,m2,rust
--enable-obsolete --enable-secureplt --disable-werror --with-system-zlib
--enable-nls --without-included-gettext --disable-libunwind-exceptions
--enable-checking=yes,extra,rtl --with-bugurl=https://bugs.gentoo.org/
--with-pkgversion='Gentoo Hardened 15.0.9999 p, commit
43e87541519c3e496094d7febd6b772ce0fb33b9' --with-gcc-major-version-only
--enable-libstdcxx-time --enable-lto --disable-libstdcxx-pch --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
--enable-multilib --with-multilib-list=m32,m64 --disable-fixed-point
--enable-targets=all --enable-offload-defaulted
--enable-offload-targets=nvptx-none --enable-libgomp --disable-libssp
--enable-libada --disable-cet --disable-systemtap --enable-valgrind-annotations
--disable-vtable-verify --disable-libvtv --with-zstd --with-isl
--disable-isl-version-check --enable-default-pie --enable-host-pie
--enable-host-bind-now --enable-default-ssp --disable-fixincludes
--with-gxx-libcxx-include-dir=/usr/include/c++/v1
--with-build-config='bootstrap-O3 bootstrap-lto'
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 15.0.1 20250403 (experimental)
92ca72b41a74aef53978cadbda33dd38b69d3ed3 (Gentoo Hardened 15.0.9999 p, commit
43e87541519c3e496094d7febd6b772ce0fb33b9)
```
