https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126038
Bug ID: 126038
Summary: [contracts] Internal compiler error in
gimplify_var_or_parm_decl, at gimplify.cc:3426 via
lambda contract captures
Product: gcc
Version: 16.1.1
URL: https://github.com/Zuhaitz-dev/cpp26-contracts/tree/ma
in/bugs
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: zuhaitz.zechhub at gmail dot com
Target Milestone: ---
Host: x86_64-redhat-linux
Target: x86_64-redhat-linux
Build: x86_64-redhat-linux
Created attachment 64896
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=64896&action=edit
Preprocessed source.
Placing a C++26 pre() or post() contract condition on a C++11 lambda expression
that captures variables from the surrounding local scope by reference (or
value) triggers an Internal Compiler Error (ICE). The middle-end fails to
properly resolve captured variables within the compiler-synthesized contract
validation block during the Gimplification phase.
EXACT GCC VERSION:
gcc version 16.1.1 20260515 (Red Hat 16.1.1-2) (GCC)
SYSTEM TYPE / TARGET:
Target: x86_64-redhat-linux
CONFIGURE OPTIONS:
../configure --enable-bootstrap
--enable-languages=c,c++,fortran,objc,obj-c++,ada,go,d,m2,cobol,algol68,lto
--prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugzilla.redhat.com/ --enable-shared
--enable-threads=posix --enable-checking=release --enable-multilib
--with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions
--enable-gnu-unique-object --enable-linker-build-id
--with-gcc-major-version-only --enable-libstdcxx-backtrace
--with-libstdcxx-zoneinfo=/usr/share/zoneinfo --with-linker-hash-style=gnu
--enable-plugin --enable-initfini-array
--with-isl=/builddir/build/BUILD/gcc-16.1.1-build/gcc-16.1.1-20260515/obj-x86_64-redhat-linux/isl-install
--enable-offload-targets=nvptx-none,amdgcn-amdhsa --enable-offload-defaulted
--without-cuda-driver --enable-gnu-indirect-function --enable-cet
--with-tune=generic --with-tls=gnu2 --with-arch_32=i686
--build=x86_64-redhat-linux --with-build-config=bootstrap-lto
--enable-link-serialization=1 --disable-libssp
COMPLETE COMMAND LINE TRIGGERING THE BUG:
g++ -std=c++26 -fcontracts -save-temps bug_lambda_ice.cpp
COMPILER OUTPUT:
bug_lambda_ice.cpp: In lambda function:
bug_lambda_ice.cpp:5:56: internal compiler error: in gimplify_var_or_parm_decl,
at gimplify.cc:3426
5 | auto dynamic_check = [&limit](int value) pre(value < limit) {};
| ~~~~~~^~~~~~~
/usr/libexec/gcc/x86_64-redhat-linux/16/cc1plus -fpreprocessed
a-bug_lambda_ice.ii -quiet -dumpdir a- -dumpbase bug_lambda_ice.cpp
-dumpbase-ext .cpp -mtune=generic -march=x86-64 -mtls-dialect=gnu2 -std=c++26
-fcontracts -foffload-options=-l_GCC_stdc++ -foffload-options=-l_GCC_m -o
a-bug_lambda_ice.s
MINIMAL STANDALONE SOURCE CODE:
#include <contracts>
int main() {
int limit = 10;
auto dynamic_check = [&limit](int value) pre(value < limit) {};
dynamic_check(5);
}
