Re: [PR68432 00/26] Handle size/speed choices for internal functions

[Bernd Schmidt <bschmidt at redhat dot com>]

On 11/25/2015 01:20 PM, Richard Sandiford wrote:
> This series fixes PR 68432, a regression caused by my internal-functions-
> for-optabs series.  Some of the libm optabs in i386.md have a true HAVE_*
> condition but conditionally FAIL if we're optimising for size:
>
>    if (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH
>        && !flag_trapping_math)
>      {
>        if (TARGET_ROUND)
> 	emit_insn (gen_sse4_1_round<mode>2
> 		   (operands[0], operands[1], GEN_INT (ROUND_MXCSR)));
>        else if (optimize_insn_for_size_p ())
>          FAIL;
>        else
> 	ix86_expand_rint (operands[0], operands[1]);
>      }

How many such cases are there? Is it just the ix86 patterns? And, could 
the same effect be achieved by just moving the optimize_insn_for_size_p 
test into the predicate (as some existing patterns already do), and then 
testing the predicate while ensuring that optimize_insn_for_x returns 
the right value? That seems like a minimal fix, and I think one that 
would be vastly more appropriate for stage 3. The alternative splitting 
looks error-prone and may not be optimal, and I still have misgivings 
about the new attribute syntax and its application to define_expands.


Bernd