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Re: inserting instructions into prologue/epilogue
On Wed, Aug 03, 2005 at 10:49:49AM -0700, Ian Lance Taylor wrote:
> Gunther Nikl <email@example.com> writes:
> > "Attempt to delete prologue/epilogue insn"
> > unless the stackslot was marked with MEM_VOLATILE_P. I don't think thats
> > the proper fix.
> As Nathan said, you can add a USE. Or in some cases the correct fix
> is to define EPILOGUE_USES and/or EH_USES.
Is EPILOGUE_USES only for the save and restore? I would have to add
some big chunk of code to it and that would propagate to several
places. It seems emitting a USE has lower impact.
> In some cases this error message can indicate a bug in the
> prologue/epilogue code.
Here is what I am trying to do: I have a rs6000 port using V.4 ABI.
The ABI has two fixed registers: r2 (_SDA2_BASE_) and r13 (_SDA_BASE_).
I suppose normally these are initialized in an assembly file. I want
the compiler emitting the appropriate load through a function attribute.
Since I change the register it has to be saved and restored as well.