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Re: Reload bug & SRA oddness


On May  9, 2007, Roman Zippel <zippel@linux-m68k.org> wrote:

> (insn 5 4 6 ../gcc/gcc/testsuite/gcc.c-torture/execute/bf64-1.c:28 (set (reg:HI 32)
>         (const_int 291 [0x123])) -1 (nil)
>     (nil))

> (insn 6 5 7 ../gcc/gcc/testsuite/gcc.c-torture/execute/bf64-1.c:28 (set (subreg:SI (reg:DI 33) 4)
>         (zero_extract:SI (subreg:SI (reg:HI 32) 0)
>             (const_int 12 [0xc])
>             (const_int 16 [0x10]))) -1 (nil)
>     (nil))

> The offset is wrong here and so the test later fails then it extracts the 
> value again.

Thanks, I'll look into that.

> One other thing I noticed is that now patterns like "(zero_extract:SI 
> (reg:SI) 32 0)" are generated which could simply be replaced with 
> (reg:SI).

Ugh.  I didn't bother optimizing these away because I was sure
something else would take care of them.  Now that I don't it won't,
I'll avoid emitting it in the first place, thanks.

-- 
Alexandre Oliva         http://www.lsd.ic.unicamp.br/~oliva/
FSF Latin America Board Member         http://www.fsfla.org/
Red Hat Compiler Engineer   aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist  oliva@{lsd.ic.unicamp.br, gnu.org}


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