Re: [PATCH] Fix LRA ICE in lra_substitute_pseudo on DEBUG_INSN (PR rtl-optimization/83723)

[Vladimir Makarov <vmakarov@redhat.com>]

On 02/14/2018 04:01 PM, Jakub Jelinek wrote:
> Hi!
>
> Unlike normal insns where SUBREGs must properly validate, in
> DEBUG_INSNs we allow arbitrary SUBREGs, either the dwarf2out code
> will be able to use it, or it will just punt.  The reason for it is
> among other things that during analysis we usually need to ignore
> debug insns, so can't reject some optimization just because it would
> create subreg in debug insn that doesn't validate, and resetting such
> debug insns is too big hammer.
>
> On the following testcase on i?86 we ICE because we have a SFmode
> pseudo and want to use a XFmode new_reg for it and such subreg doesn't
> validate on i386.
>
> Fixed by using gen_rtx_raw_SUBREG in DEBUG_INSNs as other passes do.
> We don't have gen_lowpart_raw_SUBREG, so the patch inlines what
> gen_lowpart_SUBREG does to compute the offset and uses gen_rtx_{,raw_}SUBREG
> in all cases.  Bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
Yes.  Thank you, Jakub.
> 2018-02-14  Jakub Jelinek  <jakub@redhat.com>
>
> 	PR rtl-optimization/83723
> 	* lra-int.h (lra_substitute_pseudo): Add DEBUG_P argument.
> 	* lra.c (lra_substitute_pseudo): Likewise.  If true, use
> 	gen_rtx_raw_SUBREG instead of gen_rtx_SUBREG.  Pass DEBUG_P to
> 	recursive calls.
> 	(lra_substitute_pseudo_within_insn): Adjust lra_substitute_pseudo
> 	callers.
> 	* lra-constraints.c (inherit_reload_reg, split_reg): Likewise.
>
> 	* gcc.dg/pr83723.c: New test.
>