From: Jakub Jelinek <jakub@redhat.com>
To: Richard Biener <richard.guenther@gmail.com>
Cc: Eric Botcazou <ebotcazou@adacore.com>,
GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [patch] Fix GC issue triggered by arithmetic overflow checking
Date: Thu, 13 Oct 2016 10:37:00 -0000 [thread overview]
Message-ID: <20161013103735.GD7282@tucnak.redhat.com> (raw)
In-Reply-To: <CAFiYyc1Q3mZ2w9rWOC9CuEwYvvOYVN=J4Qe_HobkFe1fOKN_aw@mail.gmail.com>
On Thu, Oct 13, 2016 at 12:19:53PM +0200, Richard Biener wrote:
> > (note 6350 6349 6351 (var_location temp (nil)) NOTE_INSN_VAR_LOCATION)
> > (note 6351 6350 6352 (var_location temp$low (mem/c:DI (plus:SI (reg/f:SI 30
> > %fp)
> > (const_int -112 [0xffffffffffffff90])) [10 MEM[(struct cpp_num
> > *)&result + 8B]+0 S8 A64])) NOTE_INSN_VAR_LOCATION)
> > (note 6352 6351 6353 (var_location temp$8 (nil)) NOTE_INSN_VAR_LOCATION)
> > [...]
> > (code_label 2091 6355 2092 79 912 "" [1 uses])
> > (note 2092 2091 5271 79 [bb 79] NOTE_INSN_BASIC_BLOCK)
> >
> > is interpreted differently from:
> >
> > (note 6350 6349 6351 (var_location temp (nil)) NOTE_INSN_VAR_LOCATION)
> > (note 6351 6350 6352 (var_location temp$8 (nil)) NOTE_INSN_VAR_LOCATION)
> > (note 6352 6351 6353 (var_location temp$low (mem/c:DI (plus:SI (reg/f:SI 30
> > %fp)
> > (const_int -112 [0xffffffffffffff90])) [10 MEM[(struct cpp_num
> > *)&result + 8B]+0 S8 A64])) NOTE_INSN_VAR_LOCATION)
> > [...]
> > (note 2092 2091 5271 79 [bb 79] NOTE_INSN_BASIC_BLOCK)
> >
> > @@ -32608,6 +32608,17 @@
> > .uleb128 0x8
> > .byte 0x93 ! DW_OP_piece
> > .uleb128 0x8
> > + .uaword .LLVL592-.LLtext0 ! Location list begin address
> > (*.LLLST153)
> > + .uaword .LLVL597-.LLtext0 ! Location list end address
> > (*.LLLST153)
> > + .uahalf 0x9 ! Location expression size
> > + .byte 0x93 ! DW_OP_piece
> > + .uleb128 0x8
> > + .byte 0x8e ! DW_OP_breg30
> > + .sleb128 -112
> > + .byte 0x93 ! DW_OP_piece
> > + .uleb128 0x8
> > + .byte 0x93 ! DW_OP_piece
> > + .uleb128 0x8
> > .uaword .LLVL695-.LLtext0 ! Location list begin address
> > (*.LLLST153)
> > .uaword .LLVL696-.LLtext0 ! Location list end address
> > (*.LLLST153)
> > .uahalf 0xe ! Location expression size
> >
> > probably because the non-null location comes last in the second case.
>
> Definitely looks like a bug to me. Can you open a PR for this so it doesn't get
> lost?
I guess it depends on whether temp$8 and temp$low overlap or not. If they
overlap, then the different orders of course matter and should matter.
Jakub
next prev parent reply other threads:[~2016-10-13 10:37 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-08 18:56 Eric Botcazou
2016-10-10 8:59 ` Richard Biener
2016-10-10 10:38 ` Eric Botcazou
2016-10-10 10:45 ` Richard Biener
2016-10-11 8:05 ` Eric Botcazou
2016-10-16 18:57 ` Eric Botcazou
2016-10-17 8:40 ` Richard Biener
2016-10-10 10:49 ` Richard Biener
2016-10-13 10:16 ` Eric Botcazou
2016-10-13 10:20 ` Richard Biener
2016-10-13 10:37 ` Jakub Jelinek [this message]
2016-10-13 10:59 ` Eric Botcazou
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