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Re: GCSE considers read only memory clobbered by function calls.
- From: Jeffrey A Law <law at redhat dot com>
- To: Mostafa Hagog <MUSTAFA at il dot ibm dot com>
- Cc: stevenb at suse dot de, gcc at gcc dot gnu dot org
- Date: Mon, 09 May 2005 09:17:45 -0600
- Subject: Re: GCSE considers read only memory clobbered by function calls.
- References: <OFBAA786E9.115D4B94-ON43256FFC.0047BCC1-43256FFC.00510FD2@il.ibm.com>
- Reply-to: law at redhat dot com
On Mon, 2005-05-09 at 17:45 +0300, Mostafa Hagog wrote:
>
>
>
> It appears that GCSE considers "read only memory" as call clobbered, which
> is not the case in CSE. I have took the test for read-only memory from CSE
> and add it to GCSE where we compute the transparency. Here is a patch that
> does so. This patch makes gcse eliminate redundant loads after stores for
> the following example. The difference is seen when we compile with the
> options:
> "-O3 --param max-gcse-passes=3" with/without "-fgcse-las" (on a
> powerpc-linux target). If this looks a reasonable change I will
> regression-test and bootstrap the patch and ask for commit.
>
[ ... ]
Yes, it looks quite reasonable. Please go ahead with the full testing
cycle and consider the patch pre-approved once complete.
jeff