[PATCH] D156657: [ValueTracking][NFC] Fold icmp(constants[x]) when the range of x is given

[Hongyu Chen via Phabricator via llvm-commits]

XChy created this revision.
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This patch extends **isImpliedCondICmps** to fold IR below:

  define i1 @cmp_load_constant_array0(i64 %x){
  entry:
    %cond = icmp ult i64 %x, 2
    br i1 %cond, label %case1, label %case2
  
  case2:
    ret i1 0
  
  case1:
    %isOK_ptr = getelementptr inbounds i32, ptr @CG, i64 %x
    %isOK = load i32, ptr %isOK_ptr
    %cond_inferred = icmp ult i32 %isOK, 3
    ret i1 %cond_inferred
  }

If D152838 <https://reviews.llvm.org/D152838> is accepted, that would be better for complex situation


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D156657

Files:
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/test/Transforms/InstCombine/load-cmp-index.ll

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