[Bug target/38201] -mfma/-mavx and -msse5/-msse4a don't work together

[hjl dot tools at gmail dot com]

------- Comment #11 from hjl dot tools at gmail dot com  2008-11-22 15:09 -------
(In reply to comment #10)
> We should have -mfma to enable a fused multiply-add instruction that is
> available
> when enabling either -msse5 or -mavx.  -mfma should not itself enable any
> of the instruction set enabling features.
> 
> HJ, why did you need -mfma and could not have used -mfused-madd for this?
> IMHO -mfma is confusing and should be removed.
> 

Intel FMA is a separate instruction set with its own feature bit in CPUID.
Using -mfused-madd -mavx to enable an instruction set doesn't look
appropriate to me.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38201