[PATCH] D100372: [Clang][ARM] Define __VFP_FP__ macro unconditionally

Wed Apr 14 05:27:08 PDT 2021

peter.smith accepted this revision.
peter.smith added reviewers: compnerd, rengolin.
peter.smith added a comment.
This revision is now accepted and ready to land.

I think this is the right thing to do. GCC changed to unconditionally set the macro with https://gcc.gnu.org/legacy-ml/gcc-patches/2016-10/msg01025.html my understanding is that the macro means that floating point representation uses the VFP format and not the FPA format (predecessor to VFP, not supported by clang, found in very old systems), it does not mean that there is a VFP unit present.

see https://wiki.debian.org/ArmEabiPort for the mutually exclusive `__MAVERICK__` whcih refers to https://wiki.debian.org/ArmEabiMaverickCrunch the processor that had the FPA FPU.

I've set LGTM, and added a few more non-Arm people involved in the area for visibility, will be good to give them a chance to comment before committing.

================
Comment at: clang/lib/Basic/Targets/ARM.cpp:758

+  Builder.defineMacro("__VFP_FP__");
+
----------------
Worth a comment like "__VFP_FP__ means that the floating point format is VFP, not that a hardware FPU is present. The VFP format is the only one supported by clang."

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https://reviews.llvm.org/D100372