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Re: [PATCH] Speed up the compiler/bootstrap on IA-32
- From: Mark Mitchell <mark at codesourcery dot com>
- To: Roger Sayle <roger at eyesopen dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Sun, 19 Sep 2004 14:00:34 -0700
- Subject: Re: [PATCH] Speed up the compiler/bootstrap on IA-32
- Organization: CodeSourcery, LLC
- References: <Pine.LNX.email@example.com>
Roger Sayle wrote:
Yes, as that will improve not only bootstrap times but compile-time
performance in general.
The following simple patch allows GCC itself to take advantage of
the recent ability to debug x86 executables without a frame pointer,
and the associated performance improvements. This patch makes use
of the recently added ability to override the default BOOT_CFLAGS
in host Makefile fragments, to add "-fomit-frame-pointer" to the
stage2 and stage3 compiler flags on selected i86 systems.
On a 2.8GHz Pentium4 system running RedHat 9, i686-pc-linux-gnu, this
change reproducably reduces the user time reported by "time make
bootstrap", for all default languages and runtime librarues, from 65m48
(3948s) to 64m53 (3893s), a saving of 55 seconds, or about 1.4% of total
bootstrap time. Considering the fraction of time spent in as, ld, sh,
make, etc... the actual improvements to compiler performance are
[Of course, if we omitted the frame pointer by default, we'd also speed
up the as, ld, sh and make above, which is something people might think
about in their extra minute of free time per bootstrap :>]
The following patch has been tested on i686-pc-linux-gnu with a full
"make bootstrap", all default languages, and regression tested with a
top-level "make -k check" with no new failures.
Ok for mainline?