[Bug tree-optimization/33761] non-optimal inlining heuristics pessimizes gzip SPEC score at -O3

[rguenther at suse dot de]

------- Comment #6 from rguenther at suse dot de  2007-12-10 17:13 -------
Subject: Re:  non-optimal inlining heuristics
 pessimizes gzip SPEC score at -O3

On Mon, 10 Dec 2007, ubizjak at gmail dot com wrote:

> (In reply to comment #4)
> 
> > Fair enough. It looks that this problem is specific to Core2.
> 
> Here are timings with 'gcc version 4.3.0 20071201 (experimental) [trunk
> revision 130554] (GCC)' on
> 
> vendor_id       : GenuineIntel
> cpu family      : 6
> model           : 15
> model name      : Intel(R) Core(TM)2 CPU         X6800  @ 2.93GHz
> stepping        : 5
> cpu MHz         : 2933.389
> cache size      : 4096 KB
> 
> -mtune=generic -m32 -O3: 40.763s   [*]
> -mtune=generic -m32 -O2: 32.170s
> -mtune=core2 -m32 -O3  : 36.850s
> -mtune=core2 -m32 -O2  : 32.170s
> 
> -mtune=generic -m64 -O3: 28.550s
> -mtune=generic -m64 -O2: 28.682s
> -mtune=core2 -m64 -O3  : 28.670s
> -mtune=core2 -m64 -O2  : 28.714s
> 
> With __attribute__((noinline)) to longest_match():
> 
> -mtune=generic -m32 -O3: 30.658s
> -mtune=generic -m32 -O2: 32.154s
> -mtune=core2 -m32 -O3  : 30.690s
> -mtune=core2 -m32 -O2  : 32.247s
> 
> And with FC6 system compiler 'gcc version 4.1.1 20061011 (Red Hat 4.1.1-30)':
> 
> -mtune=generic -m32 -O3: 30.154s   [**]
> -mtune=generic -m32 -O2: 30.275s
> 
> Comparing [*] to [**], it _is_ a regression, at least on Core2.

FSF GCC 4.1 does not have -mtune=generic.

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33761