[PATCH] D151799: [ConstraintElim] Try to use first cmp to prove second cmp for ANDs.

[Antonio Frighetto via Phabricator via llvm-commits]

antoniofrighetto added a comment.

LG! Perhaps worth to add something along these lines?

  define i1 @test_icmp_proved_by_previous_icmp(i64 %x, i64 %y, i64 %z) {
    %assumption = icmp sgt i64 %y, %z
    call void @llvm.assume(i1 %assumption)  ; assume y > z
    %1 = icmp sgt i64 %x, %y                ; check if x > y
    %2 = icmp sgt i64 %x, %z                ; check if x > z
    %cond = and i1 %1, %2
    br i1 %cond, label %t1, label %f1
  
  t1:
    ret i1 true
  
  f1:
    ret i1 false
  }

As `x > z` is implied, the second `icmp` should always be true.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D151799/new/

https://reviews.llvm.org/D151799