http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58269
--- Comment #13 from Dominique d'Humieres <dominiq at lps dot ens.fr> --- > Yes, confirmed that on x86_64-linux r202286 is the culprit. See pr58139 comments #6 to #11. I have successfully bootstrapped r202312 on x86_64-apple-darwin10 with the following patch: --- /opt/gcc/_clean/gcc/config/i386/i386.c 2013-08-28 18:59:22.000000000 +0200 +++ /opt/gcc/work/gcc/config/i386/i386.c 2013-09-06 10:46:46.000000000 +0200 @@ -4218,7 +4218,7 @@ ix86_conditional_register_usage (void) /* If AVX512F is disabled, squash the registers. */ if (! TARGET_AVX512F) - for (i = FIRST_EXT_REX_SSE_REG; i < LAST_EXT_REX_SSE_REG; i++) + for (i = FIRST_EXT_REX_SSE_REG; i <= LAST_EXT_REX_SSE_REG; i++) fixed_regs[i] = call_used_regs[i] = 1, reg_names[i] = ""; } @@ -5708,7 +5708,8 @@ ix86_function_arg_regno_p (int regno) if (TARGET_MACHO) { - if (SSE_REGNO_P (regno) && TARGET_SSE) + if (SSE_REGNO_P (regno) && TARGET_SSE + && ! EXT_REX_SSE_REGNO_P (regno)) return true; } else @@ -34466,7 +34467,7 @@ ix86_hard_regno_mode_ok (int regno, enum /* OImode move is available only when AVX is enabled. */ return ((TARGET_AVX && mode == OImode) - || VALID_AVX256_REG_MODE (mode) + || (TARGET_AVX && VALID_AVX256_REG_MODE (mode)) || VALID_SSE_REG_MODE (mode) || VALID_SSE2_REG_MODE (mode) || VALID_MMX_REG_MODE (mode) Note that the first hunk is r202318 and that without the second hunk, bootstrap fails with Comparing stages 2 and 3 warning: gcc/cc1-checksum.o differs warning: gcc/cc1obj-checksum.o differs warning: gcc/cc1objplus-checksum.o differs warning: gcc/cc1plus-checksum.o differs Bootstrap comparison failure! libiberty/md5.o differs libiberty/regex.o differs