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Re: gcse pass: expression hash table
On Thu, 2005-02-24 at 03:15, Steven Bosscher wrote:
> On Feb 24, 2005 11:13 AM, Tarun Kawatra <tarun@cse.iitb.ac.in> wrote:
> Does GCSE look into stuff in PARALLELs at all? From gcse.c:
Shrug. The code in hash_scan_set seems to be doing something
reasonable.
The problem I saw wasn't with finding expressions to gcse, it was with
inserting them later. The insertion would create a cc reg clobber, so
we don't bother adding it to the hash table. I didn't look any further,
but it seemed reasonable that if it isn't in the hash table, then it
isn't going to be optimized.
It seems that switching the x86 backend from using cc0 to using a cc
hard register has effectively crippled the RTL gcse pass for it.
--
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com