Description: Use native x86_64 instructions on x32 This patch enables a few native 64-bit integer instructions on x32 which are available on this architecture despite using 32-bit pointers. These instructions are present on x86_64 but not on x86 and ghc checks the size of (void *) to determine that. This method fails on x32 since despite using 32-bit pointers and hence sizeof(void *) == 4, it still uses the full x86_64 instruction set and software-emulated variants of the aforementioned 64-bit integer instructions are therefore not present in the toolchain which will make ghc fail to build on x32. See: https://ghc.haskell.org/trac/ghc/ticket/11571 . Index: ghc-8.0.2/rts/RtsSymbols.c =================================================================== --- ghc-8.0.2.orig/rts/RtsSymbols.c +++ ghc-8.0.2/rts/RtsSymbols.c @@ -857,7 +857,7 @@ // 64-bit support functions in libgcc.a -#if defined(__GNUC__) && SIZEOF_VOID_P <= 4 && !defined(_ABIN32) +#if defined(__GNUC__) && SIZEOF_VOID_P <= 4 && !defined(_ABIN32) && !(defined(__x86_64__) && defined(__ILP32__)) #define RTS_LIBGCC_SYMBOLS \ SymI_NeedsProto(__divdi3) \ SymI_NeedsProto(__udivdi3) \