Try isolate the int8_t constant folding testing from the rest to see if the slow down can be reproduced with the isolated case. If the problem disappear, it is likely due to the following inline parameters:
large-function-insns, large-function-growth, large-unit-insns, inline-unit-growth. For instance set --param large-function-insns=10000 --param large-unit-insns=20000 David On Mon, Aug 1, 2011 at 11:43 AM, Oleg Smolsky <oleg.smol...@riverbed.com> wrote: > On 2011/7/29 14:07, Xinliang David Li wrote: >> >> Profiling tools are your best friend here. If you don't have access to >> any, the least you can do is to build the program with -pg option and >> use gprof tool to find out differences. > > The test suite has a bunch of very basic C++ tests that are executed an > enormous number of times. I've built one with the obvious performance > degradation and attached the source, output and reports. > > Here are some highlights: > v4.1: Total absolute time for int8_t constant folding: 30.42 sec > v4.6: Total absolute time for int8_t constant folding: 43.32 sec > > Every one of the tests in this section had degraded... the first half more > than the second. I am not sure how much further I can take this - the > benchmarked code is very short and plain. I can post disassembly for one > (some?) of them if anyone is willing to take a look... > > Thanks, > Oleg. >
