[PATCH] Turn -gcse-las and -gcse-sm on by default at -O3

Tehila Meyzels TEHILA@il.ibm.com
Mon Sep 10 13:07:00 GMT 2007


I'd like to submit a patch that turns on -gcse-las and -gcse-sm, by default
at -O3.
These flags suppose to be pretty stable.
I've started checking the influence of it, including: bootstrapping,
regtesting, compilation time and performance (SPEC2000, EEMBC).
If someone can check it on other architectures, like: x86_64, s390, arm,
ia-64 and others, that would be highly appreciated!

Till now:
On powerpc-linux and on i386-linux: bootstrap OK, no regressions on

Any objections/suggestions/comments?
Would it be OK to commit this patch if there are no performance
degradations and compilation time increase?



      * opts.c (decode_options): Turn on -gcse-las and -gcse-sm at -O3.

Index: opts.c
--- opts.c      (revision 127919)
+++ opts.c      (working copy)
@@ -858,6 +858,8 @@

   if (optimize >= 3)
+      flag_gcse_las = 1;
+      flag_gcse_sm = 1;
       flag_predictive_commoning = 1;
       flag_inline_functions = 1;
       flag_unswitch_loops = 1;

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