#7684: cgrun071 segfaults ----------------------------------+---------------------------------- Reporter: tibbe | Owner: 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 rwbarton): In the #7383 "promote arguments" patch, shouldn't the new line 2060 read {{{ let prom_args = map (maybePromoteCArg dflags W64 {- not W32 -}) args }}} But anyways, I can't see why the code generator would think the argument of the `MO_PopCnt W8` operation is an 8-bit quantity—it comes from a Haskell `Word#`, and the type of the `popCnt8#` primop is `Word# -> Word#`. So we shouldn't expect the "promote arguments" patch to do anything here. Can't we just fix this by changing the definition of `hs_popcnt8` from {{{ extern StgWord hs_popcnt8(StgWord8 x); StgWord hs_popcnt8(StgWord8 x) { return popcount_tab[(unsigned char)x]; } }}} to {{{ extern StgWord hs_popcnt8(StgWord x); StgWord hs_popcnt8(StgWord x) { return popcount_tab[(unsigned char)x]; } }}} (and the same for hs_popcnt16, etc.)—then everybody will think that the argument to `hs_popcnt8` is a word rather than a single byte, and gcc 4.2 will be forced to output the same code as gcc 4.8. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/7684#comment:33 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler