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[Bug rtl-optimization/31849] [4.2/4.3 Regression] Code size regression caused by fix to PR 31360
- From: "rakdver at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 7 May 2007 10:22:34 -0000
- Subject: [Bug rtl-optimization/31849] [4.2/4.3 Regression] Code size regression caused by fix to PR 31360
- References: <bug-31849-374@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #8 from rakdver at gcc dot gnu dot org 2007-05-07 11:22 -------
(In reply to comment #7)
> Here's another example of code that is now significantly worse (~20% larger).
> Rather than incrementing the base pointers on each iteration of the loop, we
> now maintain both base pointers and and offset. This costs two extra registers
> for no benefit at all.
actually, this should save one addition (only the index is incremented, the
additions of index to bases are done in the addressing mode). Since we do not
run out of registers, this seems to be the correct thing to do.
However, for some reason we do not currently eliminate the use of the final
value of dest (which should be replaced by base_of_dest + count).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31849