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

[ubizjak at gmail dot com]

------- Comment #5 from ubizjak at gmail dot com  2007-12-10 17:12 -------
(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.


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