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Re: [PATCH] Cleanup expand_shift
On Thu, 5 May 2011, Hans-Peter Nilsson wrote:
> On Thu, 5 May 2011, Richard Guenther wrote:
> > On Wed, 4 May 2011, Richard Guenther wrote:
> > > On Wed, 4 May 2011, Eric Botcazou wrote:
> > > Hm. I guess people will scream if something breaks (I can't imagine
> > > what though).
>
> AAAaaarghh! Building cris-elf is now broken.
>
> > I have applied the following after re-bootstrapping and testing on
> > x86_64-unknown-linux-gnu and re-checking the mipsel cross testcase.
> >
> > Richard.
> >
> > 2011-05-05 Richard Guenther <rguenther@suse.de>
> >
> > * expmed.c (expand_variable_shift): Rename to ...
> > (expand_shift_1): ... this. Take an expanded shift amount.
> > For rotates recurse directly not building trees for the shift amount.
> > (expand_variable_shift): Wrap around expand_shift_1.
> > (expand_shift): Adjust.
>
> PR 48908.
Ok, it seems simplify_gen_binary doesn't like VOIDmode. The following
side-steps the issue of choosing an appropriate mode for a constant
shift amount and instead computes it in HWI. Similar to the
SHIFT_COUNT_TRUNCATED path we don't bother about a CONST_DOUBLE shift
amount.
I'm going to bootstrap & regtest this on x86_64-unknown-linux-gnu
(with again zero testing coverage ...). The patch fixes the
reported ICE with a cross to cris-elf, more testing is appreciated
(though I guess autotesters will pick it up).
Does it look sane?
Thanks,
Richard.
2011-05-06 Richard Guenther <rguenther@suse.de>
PR middle-end/48908
* expmed.c (expand_shift_1): Compute adjusted constant shift
amount manually.
Index: gcc/expmed.c
===================================================================
*** gcc/expmed.c (revision 173473)
--- gcc/expmed.c (working copy)
*************** expand_shift_1 (enum tree_code code, enu
*** 2141,2151 ****
rtx new_amount, other_amount;
rtx temp1;
new_amount = op1;
! other_amount
! = simplify_gen_binary (MINUS, GET_MODE (op1),
! GEN_INT (GET_MODE_BITSIZE (mode)),
! op1);
shifted = force_reg (mode, shifted);
--- 2141,2156 ----
rtx new_amount, other_amount;
rtx temp1;
+ op1_mode = GET_MODE (op1);
new_amount = op1;
! if (op1_mode == VOIDmode)
! other_amount = GEN_INT (GET_MODE_BITSIZE (mode)
! - INTVAL (op1));
! else
! other_amount
! = simplify_gen_binary (MINUS, op1_mode,
! GEN_INT (GET_MODE_BITSIZE (mode)),
! op1);
shifted = force_reg (mode, shifted);