[PATCH] D12633: Implement ACLE 2.0 macros of chapters 6.6 and 6.7 for [ARM] and [Aarch64] targets

Renato Golin via cfe-commits cfe-commits at lists.llvm.org
Tue Sep 22 16:28:52 PDT 2015

rengolin added a comment.

In http://reviews.llvm.org/D12633#250612, @labrinea wrote:

> __ARM_FP_FAST is defined to 1 if floating-point optimizations may occur such that the computed results are different from those prescribed by the order of operations according to the C standard. Examples of such optimizations would be reassociation of expressions to reduce depth, and replacement of a division by constant with multiplication by its reciprocal.

This seems to be specific to the order of operations, which is related to "-funsafe-math-optimizations", but not necessarily the other three. If Clang has, and sets the same flags as GCC docs imply, we should only set the macro for that one flag.


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