Most armhfp distributions are using armv7-a with -mfpu=vfp3-d16 and neon optional.
When the CPU lacks neon, such as Tegra20 and Marvell Dove, llvm needs to have -d32 feature removed in order not to assume vfp3-d32 fpu. Also enforces +fp64 feature as quoting llvm:
// fp64 and d32 subtarget features are independent of each other, so we // must disable/enable both.
See also llvm-comment