movstrictqi/movstricthi fix for h8300
Jeffrey A Law
law@cygnus.com
Mon Sep 11 14:55:00 GMT 2000
In message < Pine.LNX.4.21.0009111304350.25281-100000@breve.cygnus.com >you wri
te:
> The constraint modifiers for the destinations registers of these
> patterns were specified as write-only. This could cause the compiler to
> generate a reload that clobbered data. Setting these constraint modifiers
> to read-write fixes the problem; moreover, the comment in reload.c
> (push_reload) line 1045 indicates that this is the right thing to do.
>
> 2000-09-11 Matthew Hiller <hiller@redhat.com>
>
> * config/h8300/h8300.md (movstrictqi): Changed constraint modifier
> on operand 0 to '+'.
> (movstricthi): Likewise.
Approved and installed.
For extra credit -- submit a testcase for the bug which led you to this
patch.
It also seems to me that this might be something we could have one of the
gen* programs check for since I believe every STRICT_LOW_PART is a
read/write operand. genoutput or genrecog would likely be the best
candidates.
jeff
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