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[PATCH rs6000] Increase register move cost for LR/CTR

From: Pat Haugen <pthaugen at us dot ibm dot com>
To: gcc-patches at gcc dot gnu dot org
Cc: dje at watson dot ibm dot com
Date: Tue, 15 Apr 2008 17:13:56 -0500
Subject: [PATCH rs6000] Increase register move cost for LR/CTR

The following patch increases the register move cost for LR/CTR moves in
order to bias register spill to memory instead of these SPRs.  I ran
cpu2000 with/without the patch on both Power5 and Power6 with overall spec
results both coming in in the noise range (Power5 < 1% degradation, Power6
< 1% improvement)

Bootstrapped and regtested on powerpc64-linux with no new errors.  OK for
trunk?


2008-04-15  Pat Haugen  <pthaugen@us.ibm.com>

      * config/rs6000/rs6000.c (rs6000_register_move_cost): Increase cost
of
      LR/CTR moves.


(See attached file: reg_cost.diff)


-Pat

Attachment: reg_cost.diff
Description: Binary data

Follow-Ups:
- Re: [PATCH rs6000] Increase register move cost for LR/CTR
  - From: Andrew Pinski
- Re: [PATCH rs6000] Increase register move cost for LR/CTR
  - From: David Edelsohn

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