[PATCH] D60828: [ARM] Fix armv8 features tree and add fp16fml

[Diogo N. Sampaio via Phabricator via cfe-commits]

dnsampaio created this revision.
dnsampaio added reviewers: ostannard, DavidSpickett.
Herald added subscribers: cfe-commits, kristof.beyls, javed.absar.
Herald added a project: clang.

This patch adds the fp16fml feature parser as well fixes
the FPU and the HW_FP flags when +fullfp16 and +dotprod 
features are passed, to account for pre-requisite features.

The ARM backend (ARM.td) defines this tree of feature dependencies:

   fp16  vfp3
     |  /   |
    vfp4    neon
     |          \
  fp-armv8       FeatureDotProd
     |
  fullfp16
     |
  fp16fml

However, clang does not capture that when using +fullfp16 we
also have vfp4, so compiling
tools/clang/test/CodeGen/arm_neon_intrinsics.c

with

  clang -target armv8a-linux-eabi -march=armv8.4-a+fp16 -S -emit-llvm

will give an error because vfp4 is not added to the FPU flag.

As test now we can compile that test file with the command

  clang -target armv8a-linux-eabi -march=armv8-a+fp16fml -S -emit-llvm


Repository:
  rC Clang

https://reviews.llvm.org/D60828

Files:
  lib/Basic/Targets/ARM.cpp
  test/CodeGen/arm_neon_intrinsics.c
  test/CodeGen/arm_neon_intrinsics.c.v8