On 7/3/19 5:43 PM, Segher Boessenkool wrote:
>> @@ -212,6 +214,7 @@ enum reg_class
>> #define REG_CLASS_CONTENTS \
>> { { 0x00000000, 0x00000000 }, \
>> { SIBCALL_REGS_MASK, 0 }, \
>> + { 0x7ffffefe, 0x00000000 }, \
>
> Above you said r0, r30, r31 are excluded, but this is r0, r8, r30, or
> in GCC register numbers, 0, 8, and 31? You probably should mention r8
> somewhere (it's because it is the last arg, this avoid problems, I guess?),
> and the 30/31 thing is confused some way. Maybe it is all just that one
> documentation line :-)
... and if r8 is excluded because of arguments, I suspect that this is the
wrong fix, as there's nothing inherently wrong with r7:r8 or r8:r9 as a pair,
at least that I can see.
Perhaps function_arg and/or function_arg_advance is the right place for a fix?
The calling convention says that 64-bit arguments are not split across
registers+stack, so you already shouldn't have seen (r8, [sp+0]) as a pair.
r~
