Summary:
According to the ACLE spec, "__ARM_FEATURE_FMA is defined to 1 if
the hardware floating-point architecture supports fused floating-point
multiply-accumulate".
This changes clang's behaviour from emitting this macro for v7-A and v7-R
cores to only emitting it when the target has VFPv4 (and therefore support
for the floating point multiply-accumulate instruction).
Fixes PR27216
Reviewers: t.p.northover, rengolin
Subscribers: aemerson, rengolin, cfe-commits
Differential Revision: http://reviews.llvm.org/D18963
llvm-svn: 267869
The main purpose here is that vfma/vfms should be symmetric, and they are
supported on most v7 cores.
The new ArchGuard is suggested by ACLE but prophylactic for us. Almost all CPUs
with NEON *will* have vfma, and the few exceptions I know of (e.g. Cortex-A8)
are incorrectly modelled by Clang so can't trigger a test.
Fortunately, they're getting rarer. But if we ever do support them properly
arm_neon.h should now do the right thing.
llvm-svn: 259537
Silviu Baranga