search for: d26855

...nstructions which is usually cheaper but has appropriate precision (see genReciprocalDiv in lib/Target/X86/X86InstrInfo.cpp for details). There are other similar optimizations like usage of rsqrt, etc. but at the moment we're dealing with recip estimation only - see https://reviews.llvm.org/D26855 for details. The current version of optimization is done at DAG Combiner level when we don't know the exact target instructions which will be used by CodeGen. As result we don't know the real cost of the alternative sequence and can't compare that cost with the cost of the single f...

...but has appropriate precision (see genReciprocalDiv in >> lib/Target/X86/X86InstrInfo.cpp for details). There are other similar >> optimizations like usage of rsqrt, etc. but at the moment we're >> dealing with recip estimation only - see >> https://reviews.llvm.org/D26855 for details. >> >> The current version of optimization is done at DAG Combiner level >> when we don't know the exact target instructions which will be used >> by CodeGen. As result we don't know the real cost of the alternative >> sequence and can't comp...