[PATCH] D112428: [DAG] Create fptoui.sat from clamped fptosi

[Dave Green via Phabricator via llvm-commits]

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As an extension to D111976 <https://reviews.llvm.org/D111976>, this converts clamp fptosi, clamped between 0 and (2^n)-1 to a fptoui.sat. This can greatly help on targets with conversions that naturally saturate, such as Arm.

X86 disables the transform as some of the test cases increases in size. A fptoui.sat necessitates a fp clamp without native support, so there is little use in converting if the instruction is just going to be expanded.


https://reviews.llvm.org/D112428

Files:
  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  llvm/lib/Target/X86/X86ISelLowering.h
  llvm/test/CodeGen/AArch64/fpclamptosat.ll
  llvm/test/CodeGen/AArch64/fpclamptosat_vec.ll
  llvm/test/CodeGen/ARM/fpclamptosat.ll
  llvm/test/CodeGen/RISCV/fpclamptosat.ll
  llvm/test/CodeGen/Thumb2/mve-fpclamptosat_vec.ll
  llvm/test/CodeGen/WebAssembly/fpclamptosat.ll
  llvm/test/CodeGen/WebAssembly/fpclamptosat_vec.ll

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