On Wed, 2 Dec 2015, Jeff Law wrote: > Why let NEGATE_EXPR and ABS_EXPR pass through here? I realize that these can > often be implemented with bit-twiddling, so they're usually considered > special. BUt in this case aren't we just dealing with constants and wouldn't > we want to still express the neg/abs so that we get a signal when the input > value is sNaN rather than collapse down to a constant?
See IEEE 754-2008, 5.5.1. "Implementations shall provide the following homogeneous quiet-computational sign bit operations for all supported arithmetic formats; they only affect the sign bit. The operations treat floating-point numbers and NaNs alike, and signal no exception. These operations may propagate non-canonical encodings.". -- Joseph S. Myers jos...@codesourcery.com
