[LLVMdev] Fast-math flags in constant expressions

Owen Anderson resistor at mac.com
Wed Dec 3 23:26:48 PST 2014


On Dec 3, 2014, at 12:08 AM, Sergey Dmitrouk <sdmitrouk at accesssoftek.com> wrote:

>> Out of curiosity, how would you envision fast-math flags
>> interacting with constant expressions?
> 
> They could prevent constant-folding when it leads to loosing
> floating-point exceptions at runtime.

That's the opposite of what fast math flags do.

If you want to solve that problem, I believe you want to prevent the folding of floating point instructions into constant expressions.  The direction you're going seems like a pretty major violation of the intended functionality of constant expressions.

-Owen



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