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Re: PATCH: PR target/40470: unable to fin d a register to spill in class âSSE_FIRST_REG â


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~



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