From: Dehao Chen <dehao@google.com>
To: Eric Botcazou <ebotcazou@adacore.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] Reset source location for instructions moved out of its original residing basic block
Date: Thu, 01 Nov 2012 14:36:00 -0000 [thread overview]
Message-ID: <CAO2gOZVa2oqXnj8q3sM3D7D6fV8xa-GvmgxBe7LRYk2Up6EGBA@mail.gmail.com> (raw)
In-Reply-To: <1826073.rNRXULK6yo@polaris>
On Thu, Nov 1, 2012 at 1:52 AM, Eric Botcazou <ebotcazou@adacore.com> wrote:
>> This patch tries to fix this problem by resetting the source location
>> when moving instructions to another BB. This can greatly improve the
>> debuggability of optimized code. For the attached unittest. Without
>> the patch, the debugger will always jump into line 14 even when the
>> branch at line 13 is not taken. With the patch, the problem is fixed.
>
> But this breaks coverage info! You cannot change the source location of
For optimized code, there are many optimizations that can break
coverage info. Code motion is one of them. This patch actually tries
to fix the broken coverage info, as illustrated by the unittest.
> instructions randomly like that; the rule should be that, once a location is
> set, it cannot be changed. At most it can be cleared.
If we clear the debug info for instructions moved to other BB, is it acceptable?
Thanks,
Dehao
>
>> gcc/ChangeLog:
>> 2012-10-31 Dehao Chen <dehao@google.com>
>>
>> * emit-rtl.c (reorder_insns): Reset the source location for
>> instructions moved out of its original residing basic block.
>
> No, that isn't acceptable.
>
> --
> Eric Botcazou
next prev parent reply other threads:[~2012-11-01 14:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-01 5:03 Dehao Chen
2012-11-01 8:56 ` Eric Botcazou
2012-11-01 14:36 ` Dehao Chen [this message]
2012-11-01 15:04 ` Eric Botcazou
2012-11-01 17:00 ` Dehao Chen
2012-11-01 22:57 ` Ian Lance Taylor
2012-11-01 23:07 ` Xinliang David Li
2012-11-01 23:16 ` Dehao Chen
2012-11-01 23:36 ` Xinliang David Li
2012-11-04 22:26 ` Alexandre Oliva
2012-11-26 14:47 ` Richard Biener
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