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Re: Patch for 3.4.4. Infinite memory allocation on -O3 (PR #18081).

From: Mark Mitchell <mark at codesourcery dot com>
To: Ulrich Weigand <uweigand at de dot ibm dot com>
Cc: Grigory Tolstolytkin <gtolstolytkin at ru dot mvista dot com>, gcc-patches at gcc dot gnu dot org
Date: Wed, 11 May 2005 09:59:21 -0700
Subject: Re: Patch for 3.4.4. Infinite memory allocation on -O3 (PR #18081).
References: <200505111651.j4BGphv9012129@53v30g15.boeblingen.de.ibm.com>

Ulrich Weigand wrote:

However, I've found a definite bug in 3.4 caused by this particular backport, which is also very likely the cause of the performance regression reported here: http://gcc.gnu.org/ml/gcc/2005-05/msg00523.html

This didn't matter until now as the code calls set_mem_attribute on
the MEM generated by PUT_CODE, which used to recompute the value of
the MEM_VOLATILE_P flag.  However, after your patch, such MEMs will
remain marked as volatile ...

Thank you very much for looking into these issues.

I'd suggest to either revert the MEM_VOLATILE backport(s) for 3.4.4
or else fix the regressions by something like the below patch.

I'm not going to to be tricked into chasing through a never-ending patch sequence here. I have every confidence that your changes are correct, but I think what we've proven is that there's too many non-local impacts from the patch.

I will revert the backport shortly.

Thanks,

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304

References:
- Re: Patch for 3.4.4. Infinite memory allocation on -O3 (PR #18081).
  - From: Ulrich Weigand

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