On Thu, 30 Jan 2014, Jakub Jelinek wrote:
> Hi!
>
> The following testcase ICEs on arm, because ifcvt decides to conditionalize
> a frame related instruction that restores a call saved register and adjusts
> stack pointer (== CFA) in order to merge shrink-wrapped and
> non-shrink-wrapped basic blocks. I don't see a way how to conditionalize
> DW_CFA_restore in DWARF[234] unwind info, and while for the CFA adjustment
> one perhaps could emit conditional expression, not sure if the condition
> register is easily expressible in unwind info and whether it won't be
> clobbered by later instructions.
>
> So, this patch just refuses to put COND_EXEC on frame related instructions.
>
> Kyrill has kindly bootstrapped/regtested this on arm, ok for trunk?
Sounds reasonable to me.
Thanks,
Richard.
> 2014-01-30 Jakub Jelinek <ja...@redhat.com>
>
> PR target/59923
> * ifcvt.c (cond_exec_process_insns): Don't conditionalize
> frame related instructions.
>
> * gcc.target/arm/pr59923.c: New test.
>
> --- gcc/ifcvt.c.jj 2014-01-09 08:20:55.000000000 +0100
> +++ gcc/ifcvt.c 2014-01-29 17:16:29.912259159 +0100
> @@ -338,6 +338,10 @@ cond_exec_process_insns (ce_if_block *ce
>
> gcc_assert (NONJUMP_INSN_P (insn) || CALL_P (insn));
>
> + /* dwarf2out can't coope with conditional unwind info. */
> + if (reload_completed && RTX_FRAME_RELATED_P (insn))
> + return FALSE;
> +
> /* Remove USE insns that get in the way. */
> if (reload_completed && GET_CODE (PATTERN (insn)) == USE)
> {
> --- gcc/testsuite/gcc.target/arm/pr59923.c.jj 2014-01-29 17:39:32.355116229
> +0100
> +++ gcc/testsuite/gcc.target/arm/pr59923.c 2014-01-29 17:39:10.000000000
> +0100
> @@ -0,0 +1,24 @@
> +/* PR target/59923 */
> +/* { dg-do compile } */
> +/* { dg-require-effective-target arm_thumb2_ok } */
> +/* { dg-options "-O2 -mcpu=cortex-a15 -fno-strict-aliasing -mthumb -g" } */
> +
> +struct S
> +{
> + void *s;
> + struct T { unsigned short a; unsigned char b[4], c[4]; } *t;
> +} s;
> +void bar (void *);
> +
> +void
> +foo (struct S *x, int *y)
> +{
> + if (*y > 0)
> + return;
> + else if (x->t->b[0] == 0x43 && x->t->b[1] == 0x6d && x->t->c[0] == 1)
> + x->s = &s;
> + else
> + *y = 16384;
> + if (*y > 0)
> + bar (x);
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend"orffer
