-fprofile-generate and -fprofile-use

[Steven Bosscher]

On Tuesday 30 August 2005 17:53, Peter Steinmetz wrote:
> While this doesn't explain all of the degradations discussed (some were
> showing up on older versions of the compiler), it may explain some.

There is a lot of empirical evidence that the loop optimizer already
doesn't do many useful things anymore, so this "some" is likely a
negligible some.
A more likely source of performance degradation is that loop unrolling
is enabled when profiling, and loop unrolling is almost always a bad
pessimization on 32 bits x86 targets.

Gr.
Steven