Re: PATCH: PR target/40470: unable to find a register to spill in class ‘SSE_FIRST_REG’

[Richard Henderson]

Graham Stott wrote:
> Jeff,
> 
> cant_combine_insn_p looks to be where the combind should get rejected.
> 
> It uses CLASS_LIKELY_SPILLED (REGNO_REG_CLASS (REGNO (...)) to reject
> the combine if it finds a HARD reg which is likely to be spilled.
> 
> Now on the x86 XMM0 is in MMX_REGS class which is NOT a likely spilled class hence it doen't get rejected.
> 
> Adding MMX_REGS to the set of likely spilled classes on x86 should do the
> trick.

%xmm0 is *supposed* to be in SSE_FIRST_REG class.
Are you sure you saw MMX_REG?

Now, CLASS_LIKELY_SPILLED_P in i386.h didn't get
updated when the SSE_FIRST_REG class was introduced,
so fixing that could fix the problem described.


r~