https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84436
--- Comment #11 from Martin Liška <marxin at gcc dot gnu.org> --- (In reply to Romain Geissler from comment #10) > Hi, > > FYI, I bisected this revision r265463 to introduce a regression when > building the llvm toolchain. > > If you do the following: > - build gcc 9 >= r265463 (including recent revisions from late December) > - build clang 7 or clang 8 svn with this gcc 9 (it will work) > - finally with the resulting clang, build llvm's compiler-rt > > then clang itself will ICE. Before r265463 it was not the case, and > considering the nature of the fix (missed optimization) I suspect more a gcc > bug rather than a clang one. > > The exact clang failure is: > FAILED: CMakeFiles/clang_rt.builtins-x86_64.dir/divtc3.c.o > /workdir/build/final-system/llvm-build/./bin/clang > --target=x86_64-1a-linux-gnu -DVISIBILITY_HIDDEN -O2 -mmmx -msse -msse2 > -msse3 > -I/workdir/build/final-system/llvm-temporary-static-dependencies/install/ > include > -I/workdir/build/final-system/llvm-temporary-static-dependencies/install/ > include/ncursesw -O3 -DNDEBUG -m64 -std=c11 -fPIC -fno-builtin > -fvisibility=hidden -fomit-frame-pointer -MD -MT > CMakeFiles/clang_rt.builtins-x86_64.dir/divtc3.c.o -MF > CMakeFiles/clang_rt.builtins-x86_64.dir/divtc3.c.o.d -o > CMakeFiles/clang_rt.builtins-x86_64.dir/divtc3.c.o -c > /workdir/src/llvm-8.0.0/compiler-rt/lib/builtins/divtc3.c > fatal error: error in backend: Cannot select: 0x1a4b558: ch = fsqrt > 0x199e868, 0x1a46e38, FrameIndex:i64<0> > 0x1a46e38: f80,ch = CopyFromReg 0x199e868, Register:f80 %0 > 0x1a46d68: f80 = Register %0 > 0x1a4bd10: i64 = FrameIndex<0> > In function: __divtc3 > clang-8: error: clang frontend command failed with exit code 70 (use -v to > see invocation) > clang version 8.0.0 > Target: x86_64-1a-linux-gnu > Thread model: posix > InstalledDir: /workdir/build/final-system/llvm-build/./bin > clang-8: note: diagnostic msg: PLEASE submit a bug report to > https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, > and associated run script. > clang-8: note: diagnostic msg: > ******************** > > PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT: > Preprocessed source(s) and associated run script(s) are located at: > clang-8: note: diagnostic msg: /tmp/divtc3-106b93.c > clang-8: note: diagnostic msg: /tmp/divtc3-106b93.sh > clang-8: note: diagnostic msg: > > Note: step 2 and 3 (build clang then build compiler-rt with the resulting > clang) is done automatically when bootstrapping a 2-stage PGO clang using > this cmake configuration: > https://github.com/llvm-mirror/clang/blob/master/cmake/caches/PGO.cmake > > I don't know how to help more in investigating this regression. If I can do > something, please ask. > > Cheers, > Romain Thank you for the report. Can you please provide exact steps how to build the llvm/clang?
