[llvm] Calculate KnownBits from Metadata correctly for vector loads (PR #128908)

[via llvm-commits]

LU-JOHN wrote:

> That yielded
> 
> ```
> t24: v16i8,ch = load<(load (s128) from %ir.<badref>, !alias.scope <0x7fd6d812dc28>, !noalias <0x7fd6d812dc58>, !range <0x7fd6d80869d0>)> t0, t7, undef:i64
> <0x7fd6d80869d0> = !{i128 0, i128 3}
> rustc: /usr/local/google/home/augie/Programming/big/rust/src/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:4016: llvm::KnownBits llvm::SelectionDAG::computeKnownBits(llvm::SDValue, const llvm::APInt&, unsigned int) const: Assertion `0' failed.
> ```
> 
> Hopefully that helps - I've also got things sorted so I can get the invocation open in `lldb` if that would help for me to inspect some stuff here.

Thanks this helps.  The range metadata has a 128-bit type, but the scalar type of the load is 8-bit.  This is inconsistent.  Can you send me a testcase so I can investigate how this inconsistent metadata was created?


https://github.com/llvm/llvm-project/pull/128908