[cfe-dev] [LLVMdev] C++ Expression Template Benchmarks for GCC/Clang/Intel/PGI/MSVC

Owen Anderson resistor at mac.com
Fri Jun 15 10:07:09 PDT 2012

On Jun 15, 2012, at 9:16 AM, Douglas Gregor <dgregor at apple.com> wrote:

> IIRC, Clang doesn't actually do anything with -ffast-math, either. So, an apples-to-apples comparison would not use -Ofast or -ffast-math for either. Of course, it's completely fair criticism to say that, for people who don't require exact FP math, -Ofast gives a very nice performance boost in GCC that Clang can't match.

The code generator does understand the -ffast-math flag, and there are a small number of peephole optimizations that make use of it.  However, it's not very comprehensive.


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