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Re: Combine performance regression (was: Fix PR target/18701)
- From: Ulrich Weigand <uweigand at de dot ibm dot com>
- To: rth at redhat dot com (Richard Henderson)
- Cc: Ulrich Weigand <uweigand at de dot ibm dot com>, hp at bitrange dot com (Hans-Peter Nilsson), roger at eyesopen dot com, gcc-patches at gcc dot gnu dot org
- Date: Thu, 20 Jan 2005 20:11:06 +0100 (CET)
- Subject: Re: Combine performance regression (was: Fix PR target/18701)
Richard Henderson wrote:
> Alternately, the bug is the s390 port exposing the AND as the method
> of zero extend too early. You'll note that other targets such as Alpha,
> powerpc, and sparc (which also have to do this via AND) do not expose
> this detail ever.
Unfortunately I cannot use an immediate operand for the constant 255,
so I have to reload it into a register (or use memory), which means
I have to expose this detail before reload ...
Dr. Ulrich Weigand
Linux on zSeries Development