https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84436
Romain Geissler <romain.geissler at amadeus dot com> changed:
What |Removed |Added
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CC| |romain.geissler at amadeus dot
com
--- Comment #10 from Romain Geissler <romain.geissler at amadeus dot com> ---
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
