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Re: PR2912
- To: mark at codesourcery dot com, rth at redhat dot com
- Subject: Re: PR2912
- From: mike stump <mrs at windriver dot com>
- Date: Fri, 1 Jun 2001 23:58:44 -0700 (PDT)
- Cc: gcc at gcc dot gnu dot org, weinberg at cygnus dot com
> Date: Fri, 25 May 2001 10:46:17 -0700
> From: Richard Henderson <rth@redhat.com>
> For this test case, with the fall off the end of the function,
> the register isn't actually used, but we can't tell that from
> within the peephole. The "unreturned" return value should have
> been clobbered by
> (insn 1011 1009 1012 (clobber (reg/i:SI 0 eax)) -1 (nil)
> (nil))
> but that instruction was deleted during the .23.flow2 dump.
> I'm not sure why.
@findex EPILOGUE_USES
@item EPILOGUE_USES (@var{regno})
Define this macro as a C expression that is nonzero for registers that are
used by the epilogue or the @samp{return} pattern. The stack and frame
pointer registers are already be assumed to be used as needed.
comes to mind. I don't know if this is it though. Clobbers were not
sufficient at some point in the past.