[all-commits] [llvm/llvm-project] 64987c: [ValueTracking] isNonZero sub of ptr2int's with re...

[bipmis via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 64987c648f87613102eee70ccf9ff50e4f59f55e
      https://github.com/llvm/llvm-project/commit/64987c648f87613102eee70ccf9ff50e4f59f55e
  Author: bipmis <102525366+bipmis at users.noreply.github.com>
  Date:   2023-12-20 (Wed, 20 Dec 2023)

  Changed paths:
    M llvm/lib/Analysis/ValueTracking.cpp
    M llvm/test/Analysis/ValueTracking/known-non-zero.ll
    M llvm/test/Analysis/ValueTracking/phi-known-bits.ll
    M llvm/test/Transforms/InstCombine/sub-gep.ll

  Log Message:
  -----------
  [ValueTracking] isNonZero sub of ptr2int's with recursive GEP (#68680)

When the sub arguments are ptr2int it is not possible to determine
computeKnownBits() of its arguments.
For scalar case generally sub of 2 ptr2int are converted to sub of
indexes.
However a loop with recursive GEP/PHI where the arguments to sub is of
type ptr2int, if it is possible to determine that a sub of this GEP and
another pointer with the same base is KnownNonZero we can return this.
This helps subsequent passes to optimize the loop further.