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Re: 3.0 vs 3.0.1 on oopack's Max
- To: Paolo Carlini <pcarlini at unitus dot it>
- Subject: Re: 3.0 vs 3.0.1 on oopack's Max
- From: Richard Henderson <rth at redhat dot com>
- Date: Fri, 7 Sep 2001 16:53:41 -0700
- Cc: gcc at gcc dot gnu dot org, jh at suse dot cz, jbuck at synopsys dot com
- References: <3B98CE9D.AE04A5B7@unitus.it>
On Fri, Sep 07, 2001 at 03:41:49PM +0200, Paolo Carlini wrote:
> once more, I'm writing to the list to describe a recent performance
> regression :( on a simple benchmark.
You didn't mention how the compiler was configured,
or what options you gave for compilation.
The performance regression is caused by
3.0:
> 8048912: 31 d2 xor %edx,%edx
> 8048919: 0f 97 c2 seta %dl
> 804891c: 85 d2 test %edx,%edx
3.0.1:
> 8048917: 0f 97 c0 seta %al
> 804891a: 83 e0 01 and $0x1,%eax
The 3.0.1 version has a partial register stall on %al.
r~