[PATCH] D143074: [LangRef] improve documentation of SNaN in the default FP environment

[Mak Nazečić-Andrlon via Phabricator via llvm-commits]

Muon added a comment.

The text repeats itself, since the only signaling bit changes in IEEE 754 are quieting a signaling NaN. "May not" is also ambiguous. Also, at the risk of appearing pedantic, the earlier text conflates exceptions and their associated status flags. In IEEE 754, when exceptions are signaled, the default handling raises the corresponding status flags. (Status flags are only lowered when expressly requested.)

Perhaps the following would be clearer and more accurate:
"Therefore, there is no attempt to ensure that exceptions are signaled or that status flags are changed or preserved. There is also no guarantee that signaling NaNs are handled as specified by IEEE 754. In particular, there is no guarantee that arithmetic operations quiet a signaling NaN, or that operating on a signaling NaN causes an exception to be signaled."


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https://reviews.llvm.org/D143074