[all-commits] [llvm/llvm-project] b3b993: Reland "[TTI] Add VecPred argument to getCmpSelIns...

[Florian Hahn via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: b3b993a7ad817c3c5801341fa78f34332900eb83
      https://github.com/llvm/llvm-project/commit/b3b993a7ad817c3c5801341fa78f34332900eb83
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2020-11-02 (Mon, 02 Nov 2020)

  Changed paths:
    M llvm/include/llvm/Analysis/TargetTransformInfo.h
    M llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
    M llvm/include/llvm/CodeGen/BasicTTIImpl.h
    M llvm/lib/Analysis/TargetTransformInfo.cpp
    M llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
    M llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
    M llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
    M llvm/lib/Target/ARM/ARMTargetTransformInfo.h
    M llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.cpp
    M llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.h
    M llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
    M llvm/lib/Target/PowerPC/PPCTargetTransformInfo.h
    M llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
    M llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.h
    M llvm/lib/Target/X86/X86TargetTransformInfo.cpp
    M llvm/lib/Target/X86/X86TargetTransformInfo.h
    M llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
    M llvm/lib/Transforms/Utils/SimplifyCFG.cpp
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    M llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    M llvm/test/Analysis/CostModel/AArch64/vector-select.ll
    A llvm/test/Transforms/SimplifyCFG/phi-to-select-constexpr-icmp.ll

  Log Message:
  -----------
  Reland "[TTI] Add VecPred argument to getCmpSelInstrCost."

This reverts the revert commit 408c4408facc3a79ee4ff7e9983cc972f797e176.

This version of the patch includes a fix for a crash caused by
treating ICmp/FCmp constant expressions as instructions.

Original message:

On some targets, like AArch64, vector selects can be efficiently lowered
if the vector condition is a compare with a supported predicate.

This patch adds a new argument to getCmpSelInstrCost, to indicate the
predicate of the feeding select condition. Note that it is not
sufficient to use the context instruction when querying the cost of a
vector select starting from a scalar one, because the condition of the
vector select could be composed of compares with different predicates.

This change greatly improves modeling the costs of certain
compare/select patterns on AArch64.

I am also planning on putting up patches to make use of the new argument in
SLPVectorizer & LV.