On Mon, 2012-10-08 at 03:53 +0200, Oleg Endo wrote:
> On Mon, 2012-10-08 at 09:45 +0900, Kaz Kojima wrote:
> > Oleg Endo <oleg.e...@t-online.de> wrote:
> > > The attached patch improves comparisons such as
> > > 'unsigned int <= 0x7FFFFFFF' on SH.
> > > As mentioned in the PR, for some reason, those comparisons do not go
> > > through the cstore expander. As a consequence the comparison doesn't
> > > get the chance to be canonicalized by the target code and ends up as
> > > '(~x) >> 31'.
> > > I've not investigated this further and just fixed the symptoms on SH. I
> > > don't know whether it's also an issue on other targets.
> > >
> > > Tested on rev 192142 with
> > > make -k check RUNTESTFLAGS="--target_board=sh-sim
> > > \{-m2/-ml,-m2/-mb,-m2a/-mb,-m4/-ml,-m4/-mb,-m4a/-ml,-m4a/-mb}"
> > >
> > > and no new failures.
> > > OK?
> >
> > I've run CSiBE with and without the patch for sh4-unknown-linux-gnu
> > at -O2. Only one difference in the resulted sizes: jpeg-6b/jcphuff
> > increases 5336 bytes to 5340 bytes with the patch. Could you look
> > into it?
>
> Yep, that's actually the only place in the CSiBE set where this case
> hits. The function in question is encode_mcu_AC_refine. The increase
> seems to be due to different register allocation and different spill
> code :T
> I've attached the asm diff.
I've just checked this against current trunk (rev 192193). The problem
seems to be gone. There's also a total decrease of 152 bytes on this
file without the patch. So it seems it was a different issue. The diff
is now:
--- CSiBE/m4-single-ml-O2/jpeg-6b/jcphuff_.s
+++ CSiBE/m4-single-ml-O2/jpeg-6b/jcphuff.s
@@ -2626,13 +2626,12 @@
add r0,r0
mov.l r3,@(24,r13)
bf/s .L502
- mov.w @(r0,r1),r11
+ mov.w @(r0,r1),r7
mov.l @(12,r15),r0
- not r11,r11
- shll r11
+ cmp/pz r7
mov.l @(12,r15),r10
+ movt r11
neg r0,r2
- movt r11
add #23,r2
shld r2,r11
add #1,r10
Cheers,
Oleg
