https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87015
Bug ID: 87015 Summary: [8 Regression] miscompilation of template heavy Boost Spirit code Product: gcc Version: 8.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: daniel.f.starke at freenet dot de Target Milestone: --- Starting with GCC 8.1.0 I encounter wrong code generations when using template heavy C++ code with Boost Spirit. Using Boost 1.66 with GCC 7.2.0, 7.3.0, 8.1.0 and 8.2.0 to compile https://github.com/daniel-starke/pp results in the following test case results of pp: 7.2.0 TOTAL: 767 PASSED: 767 FAILED: 0 7.3.0 TOTAL: 767 PASSED: 767 FAILED: 0 8.1.0 TOTAL: 760 PASSED: 140 FAILED: 620 8.2.0 TOTAL: 760 PASSED: 140 FAILED: 620 Tests with GCC8.2.0 did show that some errors occur because the string terminator _r2 in https://github.com/daniel-starke/pp/blob/master/src/pp/parser/Script.hpp#L396 does gets propergated to https://github.com/daniel-starke/pp/blob/master/src/pp/parser/StringLiteral.hpp#L226 but not properly set. GCC 8.2.0 was configured with: ../../src/gcc-8.2.0/configure --host=x86_64-w64-mingw32 --enable-languages=c,c++ --enable-seh-exceptions --enable-threads=posix --disable-nls --disable-shared --enable-static --enable-fully-dynamic-string --enable-lto --enable-plugins --enable-libgomp --with-dwarf2 --enable-mingw-wildcard=platform --disable-win32-registry --enable-version-specific-runtime-libs --prefix=/mingw64-64 --with-sysroot=/mingw64-64 --target=x86_64-w64-mingw32 --enable-targets=all --enable-checking=release --with-gmp=/usr/new-gcc/lib/gmp-5.0.5 --with-mpfr=/usr/new-gcc/lib/mpfr-2.4.2 --with-mpc=/usr/new-gcc/lib/mpc-0.9 --with-isl=/usr/new-gcc/lib/isl-0.18 --with-cloog=/usr/new-gcc/lib/cloog-0.18.4 --with-host-libstdcxx='-lstdc++ -lsupc++' --disable-cloog-version-check --enable-cloog-backend=isl Thread model: posix It is available here: https://sourceforge.net/projects/gcc-win64/files/8.2.0/ Due to the nature of the bug I am unable to provide a reduced test case without an better idea of what the cause of the issue is. Compiling with -Og or -O1 instead of -O2 did not change the behavior.