#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: leroux Type: bug | Status: new Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: cgrun071 | Blocked By: Blocking: | Related Tickets: ----------------------------------+---------------------------------- Comment (by leroux): The problem has been pinpointed to the fact that apple-gcc42 does not support SSE4 instructions. After carter suggested that it may be a problem with apple-gcc42, I rebuilt ghc with gcc48 and cgrun071 passed both the normal and llvm ways. It seems that carter's theory was right in that gcc 4.2 does not have support for SSE4 instructions. In fact, support for SSE4 was added in with the release of gcc43. http://gcc.gnu.org/gcc-4.3/changes.html It may be that SSE42 support isn't being detected properly by nativeGen. https://github.com/ghc/ghc/blob/master/compiler/nativeGen/X86/CodeGen.hs#L16... When reproducing this, #8148 may get in the way. carter's helpful fix is to simply symlink to `gcc-4.8` as `gcc` and, add it to your PATH, then build ghc as normal. {{{ $ mkdir ~/bin $ ln -s `which gcc-4.8` ~/bin/gcc $ export PATH=~/bin:$PATH $ # reload your shell and `gcc -v` should show 4.8 or whatever. }}} Should we switch to calling the "slower" popCount for this certain case? https://github.com/ghc/testsuite/blob/master/tests/codeGen/should_run/cgrun0... {{{ slowPopcnt :: Word -> Word slowPopcnt x = count' (bitSize x) x 0 where count' 0 _ !acc = acc count' n x acc = count' (n-1) (x `shiftR` 1) (acc + if x .&. 1 == 1 then 1 else 0) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/7684#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler