[PATCH v3] Change default to -fno-math-errno

Joseph Myers joseph@codesourcery.com
Thu Oct 4 12:27:00 GMT 2018


On Thu, 4 Oct 2018, Richard Biener wrote:

> The other issue is that we're treating -fno-math-errno as disabling
> errno handling in general (not only for math functions).  That would

Also, is it treated as meaning the math functions *do not set errno* (so a 
load of errno (or of anything that might be errno) before a math function 
call could be moved after the call)?  Because the proper meaning is simply 
*may not set errno* (so you shouldn't be able to move an errno load across 
a call like that, since the call might still happen to clobber it - of 
course if it happens to be a call that GCC inlines and eliminates any 
possibility of errno setting that way, e.g. sqrt on many platforms, or a 
platform where libm never sets errno at all, then such a move is safe).

-- 
Joseph S. Myers
joseph@codesourcery.com



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