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Re: [Patch,AVR]: Fix PR36467, PR49687 (better widening mul)
Richard Henderson schrieb:
On 07/18/2011 11:05 AM, Georg-Johann Lay wrote:
What's bad with pre-reload splits?
The only weak point is in target-independent code because there
is nothing like split1_completed and other missing information
for better pass-awareness.
Nothing's wrong with pre-reload splits.
However, what you've done is try very hard to work around reload
doing the Right Thing with constant spilling, namely re-generate
the constant rather than spill and restore it. I cannot believe
that's the right way to proceed.
You mean that with a clobber reload will rematerialize the constant
if there are not enough registers instead of spilling it?
And with an ordinary move like
(set (reg) (const_int))
reload will not see that it can reaterialize it and spill it to
the stack?
Moreover, I wonder why target-independent code does not already
catch the situation because the pattern to be generated is just
an ordinary umulqihi3 widening multiplication.
Johann