http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46796
--- Comment #2 from mrs at gcc dot gnu.org <mrs at gcc dot gnu.org> 2010-12-03 23:45:15 UTC --- >From dwarfdump of the good .o file: 0x000000a1: TAG_formal_parameter [3] AT_name( "i" ) AT_decl_file( "/Users/mrs/net/gcc-darwinLTO/gcc/t.c" ) AT_decl_line( 5 ) AT_type( {0x000000ae} ( int ) ) AT_location( fbreg -20 ) 0x000000ae: TAG_base_type [4] AT_byte_size( 0x04 ) AT_encoding( DW_ATE_signed ) AT_name( "int" ) and for the bad version: 0x00000110: TAG_formal_parameter [5] AT_name( "i" ) AT_decl_file( "/Users/mrs/net/gcc-darwinLTO/gcc/t.c" ) AT_decl_line( 5 ) AT_type( {0x000000ea} ( __unknown__ ) ) AT_location( fbreg -20 ) 0x000000ea: TAG_base_type [3] AT_byte_size( 0x04 ) AT_encoding( DW_ATE_signed ) AT_name( "__unknown__" )