[LLVMdev] detailed comparison of generated code size for LLVM and other compilers
Chris Lattner
clattner at apple.com
Mon Dec 14 13:57:23 PST 2009
On Dec 14, 2009, at 1:49 PM, John Regehr wrote:
>> You'll probably need to some digging to make sure the defaults are
>> exactly
>> comparable. Are SSE and/or MMX used? This affects floating point
>> codegen
>> quite a bit. Are the target CPUs the same?
>
> Good point. Would "generic i686" be a reasonable choice? Does that
> even
> mean anything these days?
>
> Anyway-- I'd appreciate some guidance on what you folks would find
> most
> interesting and useful. Then I can do some homework and figure out
> how to
> get the rest of the compilers to assume an equivalent ISA.
I'd recommend targeting (with both -march and -mtune) a simple and
commonly available CPU type like "core2" or "pentium4". ICC should
have both of these and gcc/llvm definitely do.
-Chris
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