http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51447
--- Comment #5 from Paolo Bonzini <bonzini at gnu dot org> 2011-12-07 14:04:04 UTC --- Untested patch... Index: df-problems.c =================================================================== --- df-problems.c (revision 177688) +++ df-problems.c (working copy) @@ -901,6 +901,10 @@ df_lr_local_compute (bitmap all_blocks A /* The all-important stack pointer must always be live. */ bitmap_set_bit (&df->hardware_regs_used, STACK_POINTER_REGNUM); + for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) + if (global_regs[i]) + bitmap_set_bit (&df->hardware_regs_used, i); + /* Before reload, there are a few registers that must be forced live everywhere -- which might not already be the case for blocks within infinite loops. */ Index: df-scan.c =================================================================== --- df-scan.c (revision 177688) +++ df-scan.c (working copy) @@ -3733,8 +3733,12 @@ df_get_entry_block_def_set (bitmap entry bitmap_clear (entry_block_defs); for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) - if (FUNCTION_ARG_REGNO_P (i)) - bitmap_set_bit (entry_block_defs, INCOMING_REGNO (i)); + { + if (global_regs[i]) + bitmap_set_bit (entry_block_defs, i); + if (FUNCTION_ARG_REGNO_P (i)) + bitmap_set_bit (entry_block_defs, INCOMING_REGNO (i)); + } /* The always important stack pointer. */ bitmap_set_bit (entry_block_defs, STACK_POINTER_REGNUM);