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Re: gcc 3.2.1 optimizer degradation (strlen, -O2)
- From: sandmann at clio dot rice dot edu (Charles Sandmann)
- To: djgpp-workers at delorie dot com
- Cc: eliz at is dot elta dot co dot il, gcc at gcc dot gnu dot org
- Date: Sat, 11 Jan 2003 16:59:28 -0600 (CST)
- Subject: Re: gcc 3.2.1 optimizer degradation (strlen, -O2)
> gcc321 -O2
> strlen.c 20 sec
> strlen2.c 17 sec
> (library?) 14 sec
The library version was compiled with gcc 2.8.1, which seems faster
than the 16 seconds below with 2.95; but in any case your modified
code seems faster.
> gcc295 -O2
> strlen.c 16 sec (main.c was compiled without -O)
> strlen2.c 11 sec (main.c was compiled without -O)
> (builtin) 8 sec
I'm not sure the accuracy of the numbers, but it appears:
2.8.1 14 seconds
2.9.5 16 seconds
3.2.1 20 seconds
A dump of the assembler for each of these would be interesting.