[PATCH] rtl: constm64_rtx..const64_rtx

Segher Boessenkool segher@kernel.crashing.org
Thu Jun 3 23:09:25 GMT 2021


On Thu, Jun 03, 2021 at 01:32:54PM -0600, Jeff Law wrote:
> On 6/2/2021 4:43 PM, Segher Boessenkool wrote:
> >We have has const0_rtx etc. since forever, this patch just increases the
> >range (to those values that have had guaranteed unique RTXes since
> >decades as well).
> Yea, but often what you really want is CONST0_RTX (mode) instead of 
> const0_rtx.   It's easily goof'd and often the cause minor missed 
> optimizations.

I'd say "sometimes" instead of "often"...  almost always you really do
want a scalar integer.  Also, although CONST0_RTX makes sense for pretty
much all modes, CONST64_RTX will not (and those are not currently unique
RTX anyway).


Segher


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