[Bug rtl-optimization/53533] [4.7/4.8 regression] vectorization causes loop unrolling test slowdown as measured by Adobe's C++Benchmark

matt at use dot net gcc-bugzilla@gcc.gnu.org
Mon Aug 20 23:53:00 GMT 2012


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53533

--- Comment #20 from Matt Hargett <matt at use dot net> 2012-08-20 23:52:31 UTC ---
Some additional information:
Compared to LLVM 3.1 with -O3, GCC 4.7 is twice as slow on these benchmarks.
LLVM even outperforms GCC 4.1, which previously had the best result. We are
very eager to hear about any resolution for this major regression in 4.7 so we
can deploy it. Even a return to GCC 4.1 performance levels would be fine.

Thanks!



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