Florian Hahn cd2fc73b49 Revert "[ValueTracking][InstCombine] Add a new API to allow to ignore poison generating flags or metadatas when implying poison" ...

This reverts commit 754f3ae655.

Unfortunately the change can cause regressions due to dropping flags
from instructions (like nuw,nsw,inbounds), prevent further optimizations
depending on those flags.

A simple example is the IR below, where `inbounds` is dropped with the
patch and the phase-ordering test added in 7c91d82ab9.

    define i1 @test(ptr %base, i64 noundef %len, ptr %p2) {
    bb:
      %gep = getelementptr inbounds i32, ptr %base, i64 %len
      %c.1 = icmp uge ptr %p2, %base
      %c.2 = icmp ult ptr %p2, %gep
      %select = select i1 %c.1, i1 %c.2, i1 false
      ret i1 %select
    }

For more discussion, see D149404.

2023-05-29 15:44:37 +01:00

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