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Re: [PATCH, rtl-optimization]: Fix PR 51821, 64bit > 32bit conversion produces incorrect results with optimizations
> Yes, it is a complete solution. Tracking register liveness is
> different issue, and a register is indeed dead after instruction, if
> it has been clobbered by insn, or when marked unused.
My concern was liveness within the new sequence of instructions: suppose you
have
(set (reg:M x) (...)) REG_UNUSED (reg:M x)
and we "peephole" the instruction. Is the live range of (reg:M x) properly
extended within the new sequence of instructions?
> The problem my patch solves is the answer to the question "Is the
> choosen non-live temporary register untouched over the insn
> sequence?". The answer: "Yes, if it was not set or clobbered by any
> insn in the sequence".
Are you sure that you don't need to do this in addition to the existing test,
instead of in lieu of the existing test?
--
Eric Botcazou