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g++ V3.3.1 not faster with __restrict
- From: "Kaspar Thommen" <kaspar at gmx dot ch>
- To: gcc-help at gcc dot gnu dot org
- Date: Fri, 21 Nov 2003 11:26:37 +0100 (MET)
- Subject: g++ V3.3.1 not faster with __restrict
Hi,
I ran some benchmarks using g++ V3.3.1. Two functions are called from a main
program. While both doing exactly the same array manipulation (dot product
on doubles), one of the functions uses the __restrict keyword to tell the
compiler that pointer aliasing is "turned off" in that function.
To my surprise, the __restrict version is not faster than the conventional
one. In fact, they show the same speed. Do I have to specify any compilation
option to tell g++ to really take advantage from the __restrict information?
Didn't find anything in the docs however. I tried using -o, -o2, -o3, giving
always equal speed for both functions.
Regards
Kaspar
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