Running Clang over itself, using preprocessed files and -fsyntax-only 28.86 to 29.08 seconds - Control 28.89 to 29.49 seconds - Clang with -Wduplicate-enum
This was run without Richard Smith's suggestions. I will test those out to see if there's any impact from them. On Wed, Jul 25, 2012 at 2:37 PM, Ted Kremenek <[email protected]> wrote: > Ok. That's still a scary number. Do you have numbers for realistic > examples? For example, we know Clang has some particularly large enums. > This micro benchmark is useful, but it may be overly pessimistic. > > On Jul 25, 2012, at 2:34 PM, Richard Trieu <[email protected]> wrote: > > Yes, that is the slowdown for the entire -fsyntax-only time for a source > file with only an enum in it. > > On Wed, Jul 25, 2012 at 1:48 PM, Ted Kremenek <[email protected]> wrote: > >> Hi Richard, >> >> If I am reading that right, the 6-10% slowdown is for the entire >> -fsyntax-only time? If so, that's definitely cost prohibitive. >> >> Ted >> >> On Jul 19, 2012, at 8:25 PM, Richard Trieu <[email protected]> wrote: >> >> On Wed, Jul 18, 2012 at 9:14 PM, Ted Kremenek <[email protected]> wrote: >> >>> On Jul 18, 2012, at 6:34 PM, Richard Trieu <[email protected]> wrote: >>> >>> A set could work for detecting the values, but both EnumConstantDecls >>> are needed for the diagnostic, not just the values. Possibly a map from >>> APSInt->EnumConstantDecl* would work. But either way, I would be dealing >>> with getting APSInts to play nice with each other. >>> >>> >>> That seems reasonable to me. The primary performance issue I see is the >>> quadratic algorithmic complexity. If the APSInt comparisons are an issue, >>> we can see if we can find ways to optimize that further. >>> >> >> I created two more variations on and measured some timings. Both used a >> map, one with a custom compare function and one that extended the APSInt >> value before insertion. The APSInt extension had the better time, so I'll >> be giving the number for that one. >> >> At 10,000 elements, there was a 6-10% slow down. This amounts to .01-.03 >> seconds difference on .13-.27 second runtime. >> >> At 100,000 elements, 8-12% slow down. .2-.3 seconds on 1.34 to 2.66 >> second run time. >> >> At 1,000,000 elements, 7-14% slow down. Around 2 second difference for >> runs of 13.6 to 26.7 seconds. >> >> A new patch has been attached which has the APSInt bit extension before >> adding to the map. >> <duplicate-enum-bit-extension.patch> >> >> >> > >
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