Daniel Jacobowitz - Re: Link-time optimzation (original) (raw)

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On Thu, Nov 17, 2005 at 03:42:29PM -0800, Ian Lance Taylor wrote:

I just tried a simple unoptimized compile. -ftime-report said that final took 5% of the time (obviously final does more than formatting), and the assembler took 4% of the total user time, and system time took 16% of wall clock time. Cutting those numbers in half makes 1% seem not implausible to me, maybe even low.

I'm considering an unoptimized compile because that is where the assembler makes the most difference--the compiler is faster and the assembler output probably tends to be longer, and also an unoptimized compile is when people care most about speed. For an optimizing compile, the assembler is obviously going to be less of a factor.

Also, please keep in mind that generating and then assembling debug info takes a huge amount of I/O relative to code size. I'd expect much more than 1% saving the write-out and write-in on -g.

-- Daniel Jacobowitz CodeSourcery, LLC

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