On 25-04-14 15:22, Richard Sandiford wrote:
> Tom de Vries <Tom_deVries@mentor.com> writes:
>> diff --git a/gcc/config/mips/mips.c b/gcc/config/mips/mips.c
>> index 45256e9..b61cd44 100644
>> --- a/gcc/config/mips/mips.c
>> +++ b/gcc/config/mips/mips.c
>> @@ -7027,11 +7027,17 @@ mips_expand_call (enum mips_call_type type, rtx result, rtx addr,
>>   {
>>     rtx orig_addr, pattern, insn;
>>     int fp_code;
>> +  rtx post_call_tmp_reg = gen_rtx_REG (word_mode, POST_CALL_TMP_REG);
>>
>>     fp_code = aux == 0 ? 0 : (int) GET_MODE (aux);
>>     insn = mips16_build_call_stub (result, &addr, args_size, fp_code);
>>     if (insn)
>>       {
>> +      if (TARGET_EXPLICIT_RELOCS
>> +	  && TARGET_CALL_CLOBBERED_GP
>> +	  && !find_reg_note (insn, REG_NORETURN, 0))
>> +	clobber_reg (&CALL_INSN_FUNCTION_USAGE (insn), post_call_tmp_reg);
>> +
>
> I think this condition should go in mips_emit_call_insn instead,
> so that we don't have 4 instances of it.  untyped_call could then
> use mips_expand_call as well.
>

Richard,

Done.

> Until now there was no real downside to using $6 for non-MIPS16 code.
> Now that there is, it would probably be worth making it:
>
> +#define POST_CALL_TMP_REG \
>    (TARGET_MIPS16 ? GP_ARG_FIRST + 2 : PIC_OFFSET_TABLE_REGNUM)
>
> and only adding the clobber for MIPS16.
>

Done.

>> diff --git a/gcc/testsuite/gcc.target/mips/fuse-caller-save.c b/gcc/testsuite/gcc.target/mips/fuse-caller-save.c
>> new file mode 100644
>> index 0000000..1fd6c7d
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/mips/fuse-caller-save.c
>> @@ -0,0 +1,30 @@
>> +/* { dg-do compile } */
>> +/* { dg-options "-fuse-caller-save" } */
>> +/* { dg-skip-if "" { *-*-* }  { "*" } { "-Os" } } */
>
> I might have asked this before, sorry, but why this skip?  Please add a brief
> comment (in the string, if short enough).

I've reduced the amount of skips a bit, and added a comment why they are skipped.

>
>> +/* Testing -fuse-caller-save optimization option.  */
>> +
>> +static int __attribute__((noinline)) NOCOMPRESSION
>> +bar (int x)
>> +{
>> +  return x + 3;
>> +}
>> +
>> +int __attribute__((noinline)) NOCOMPRESSION
>> +foo (int y)
>> +{
>> +  return y + bar (y);
>> +}
>> +
>> +int NOCOMPRESSION
>> +main (void)
>> +{
>> +  return !(foo (5) == 13);
>> +}
>> +
>> +/* Check that there are only 2 stack-saves: r31 in main and foo.  */
>> +
>> +/* Check that there only 2 sw/sd.  */
>> +/* { dg-final { scan-assembler-times "(?n)s\[wd\]\t\\\$.*,.*\\(\\\$sp\\)" 2 } } */
>> +
>> +/* Check that the first caller-save register is unused.  */
>> +/* { dg-final { scan-assembler-not "\\\$16" } } */
>
> It'd be good to avoid NOCOMPRESSION because the only case that really
> needs the temporary register is MIPS16.  Please try putting the test
> in a header file and reusing it for three tests, one each of MIPS16,
> microMIPS and uncompressed.
>

Done, I think, I'm not 100% sure I understood what you wanted me to do here.

build and reg-tested on MIPS.

OK for trunk?

Thanks,
- Tom