https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110078
Bug ID: 110078
Summary: [13 regression] Excessive memory usage constructing
std::variant from a high-index alternative.
Product: gcc
Version: 13.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: toojays at toojays dot net
Target Milestone: ---
Created attachment 55233
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55233&action=edit
Reproducer demonstrating excessive memory use constructing std::variant from a
high-index alternative.
The attached source contains a function which constructs a std::variant<29
alternatives> from the 29th alternative. Attempting to compile it with GCC 13.1
results in cc1plus consuming more than 20GiB of memory before being killed. GCC
12.2.0 is able to compile it promptly with no apparent problems.
$ g++-13 -v
Using built-in specs.
COLLECT_GCC=/opt/acacia/3rd-party/gcc-13.1.0-1/bin/g++
COLLECT_LTO_WRAPPER=/opt/acacia/3rd-party/gcc-13.1.0-1/libexec/gcc/x86_64-pc-linux-gnu/13.1.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /docker-20.04-build/extract/gcc-13.1.0/configure
--prefix=/opt/acacia/3rd-party/gcc-13.1.0-1
CPPFLAGS=-I/opt/acacia/3rd-party/gcc-13.1.0-1/include CFLAGS='-O2 -g
-fno-omit-frame-pointer' CXXFLAGS='-O2 -g -fno-omit-frame-pointer'
--enable-languages=c,c++,d --disable-multilib --with-system-zlib
--enable-checking=release --program-prefix= --program-suffix=
--with-gmp=/opt/acacia/3rd-party/gcc-13.1.0-1
--with-mpfr=/opt/acacia/3rd-party/gcc-13.1.0-1
--with-mpc=/opt/acacia/3rd-party/gcc-13.1.0-1
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.1.0 (GCC)
