[PATCH] D150542: [ValueTracking] Ensure isGuaranteedNotToBeUndefOrPoison scans CtxI's parent basic block if CtxI is given

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As far as I known, if CtxI is given in isGuaranteedNotToBeUndefOrPoison,
it means that V is guaranteedNotToBeUndefOrPoison in CtxI's parent basic
block. However, in guaranteedNotToBeUndefOrPoison, we call
programUndefinedifUndefOrPoison that only scan's V's parent basic block
if V is instruction or entry block if V is argument. That will make
isGuaranteedNotToBePoisonOrUndef return incorrect result for the
following IR, and we call isGuaranteedNotToBePoisonOrUndef('%zext',
nullptr, '%x').

  declare void @maythrow()
  declare void @use.i32(i32)
  define void @zext_sdiv_not_ok3_maybe_poison_denum(i32 noundef %nn, i16 %xx) {
  entry:
    %n = and i32 %nn, 123
    %x = or i16 %xx, 1
    br label %loop
  loop:
    call void @maythrow()
    %zext = zext i16 %x to i32
    %div = sdiv i32 %n, %zext
    call void @use.i32(i32 %div)
    br label %loop
  }

Actually, `%zext` in block `entry` is not guaranteed not to be undef or
poison. But current `isGuarnateedNotToBePoisonOrUndef` calls
programUndefIfUndefOrPoison that scans `loop` block and it returns true
since there is a sdiv instruction that uses `%zext` as divisor.

And current `isSafeToSpeculativeExecute` has not called
`isGuaranteedNotToBePoison`, but it will happen if D149423 <https://reviews.llvm.org/D149423> is landed.
And then if we call `isSafeToSpeculativeExecute(`%div`, `%x`)`, it will
return true, which is wrong.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D150542

Files:
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/test/Transforms/PhaseOrdering/AArch64/matrix-extract-insert.ll

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