On 08/09/2022 21:38, Kwok Cheung Yeung wrote:
Hello
This patch adds support for some additional floating-point operations,
in scalar and vector modes, which are natively supported by the AMD GCN
instruction set, but haven't been implemented in GCC yet. With the
exception of frexp, these implement standard RTL names, and should be
utilised automatically by GCC.
The instructions for the transcendental functions are documented to have
limited numerical precision, so they are only used if
unsafe_math_optimizations are enabled for now.
The sin and cos instructions for some reason are scaled by 2*PI radians
(i.e. 1.0 == 2*PI radians/360 degrees), so their inputs need to be
scaled by 1/(2*PI) first. I've implemented this as an expander to two
instructions - one to do the pre-scaling, one to do the sin/cos.
1/(2*PI) is a builtin constant for GCN, but the syntax to use it in the
LLVM assembler was wrong - now fixed.
I have also added some extra GCN-specific builtins to access the vector
versions of some of these operations (to implement vectorized versions
of library math routines) and to access the frexp operations.
Okay for trunk?
LGTM. I'm assuming you've checked the maths. :)
Andrew
