[gambit-list] Performance of different versions of gcc
feeley at iro.umontreal.ca
Tue May 1 12:04:16 EDT 2012
On 2012-05-01, at 11:51 AM, Hendrik Boom wrote:
> On Tue, May 01, 2012 at 09:35:24AM -0400, Marc Feeley wrote:
>> Strangely, with clang 3.0 it takes less time to compile with -O2
>> with -O1.
> If I recall correctly, this phenomenon was first noticed in the 60's
> with IBM's Fortran H compiler. It turns out that most of the time was
> spent in the final process of putting instrutions together. After
> optimizing, there was less code to generate.
I doubt that this is the explanation here. With -O1 it takes 2.4 times as long as -O1 to build Gambit, yet the resulting executable binary is the same size (actually the -O2 executable is 0.3% larger than the -O1 executable).
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