[PATCH] D114380: [ARM] Teach getIntImmCostInst about the cost of saturating fp converts

[Dave Green via Phabricator via llvm-commits]

dmgreen created this revision.
dmgreen added reviewers: SjoerdMeijer, samtebbs, ostannard, simon_tatham.
Herald added subscribers: armkevincheng, jsmolens, eric-k256, hiraditya, kristof.beyls.
Herald added a reviewer: sjarus.
dmgreen requested review of this revision.
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Given a min(max(fptosi, INT_MIN), INT_MAX) with the correct constants, we can now generate a fptosi.sat. But in the arm backend, the constant can be treated as high cost, pulling it out of the basic block in a way that the DAG combine can no longer see it. This teaches it again that it is a low cost constant, not worth hoisting out.


https://reviews.llvm.org/D114380

Files:
  llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
  llvm/test/CodeGen/ARM/fpclamptosat.ll

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