[PATCH] D62731: Add support for options -frounding-math, ftrapping-math, -fp-model=, and -fp-exception-behavior=, : Specify floating point behavior

[Melanie Blower via Phabricator via llvm-commits]

mibintc added a comment.

In D62731#1724290 <https://reviews.llvm.org/D62731#1724290>, @rjmccall wrote:

> Is the exception-strictness of `-frounding-math` actually considered to be specified behavior, or is it just a consequence of the current implementation?  There are definitely some optimizations that we can't do under strict FP exceptions that we can still do in principle while respecting a dynamic FP rounding mode; for example, the rounding mode can only be changed by a call (or inline assembly), so you can still reorder FP operations around "lesser" side effects, like stores.  We can document it even if it's not required behavior, but we should be clear about what it is.


I had thought that it was intended behavior, but I re-checked my notes and realize I was wrong about that. So I've changed the document and the driver, and updated the test. Thanks again for your careful reading.

> My suggested wording started with a sentence briefly summarizing what the option did that I think you accidentally dropped.

Yes, it's there now.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D62731/new/

https://reviews.llvm.org/D62731