4 May
2015
4 May
'15
1:40 p.m.
On 05/04/2015 08:36 PM, Levent Erkok wrote:
In particular, the compiler should be free to substitute "a*b+c" with "mulAccum a b c". But isn't it unacceptable in some cases? For instance, in this case (taken from Wikipedia): If /x/^2 − /y/^2 is evaluated as ((/x/×/x/) − /y/×/y/) using fused multiply–add, then the result may be negative even when /x/ = /y/ due to the first multiplication discarding low significance bits. This could then lead to an error if, for instance, the square root of the result is then evaluated.