[llvm-commits] [llvm] r85697 - in /llvm/trunk: lib/Target/ARM/ARMInstrNEON.td test/CodeGen/ARM/fmacs.ll test/CodeGen/ARM/fnmacs.ll test/CodeGen/Thumb2/cross-rc-coalescing-2.ll

[Anton Korobeynikov]

Hello, Jim

> vml[as].f32 cause stalls in following advanced SIMD instructions. Avoid using
> them for scalar floating point operations for now.
Basically, every vfp instruction causes stall for the adjacent neon
instruction. The stall can be up to 20 cycles long and we don't have
any proper way to model such stalls during scheduling.

However, according to ARM docs, neon vmla.f32 is cheaper than pair of
vmul + vadd, are you sure there is no e.g. assembler bug here?

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University