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

[Tim Neumann via llvm-commits]

TimNN wrote:

I was now also able to reproduce and got reduced IR, which crashes when run through `llc -O0`:

```ll
target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.12.0"

define void @"_ZN4core3ptr100drop_in_place$LT$core..option..Option$LT$regex_automata..meta..wrappers..ReverseHybridEngine$GT$$GT$17hb293fd3cea85facfE"() {
start:
  %0 = load i128, ptr null, align 16, !range !0, !noundef !1
  %1 = icmp eq i128 %0, 1
  br i1 %1, label %bb1, label %bb1

bb1:                                              ; preds = %start, %start
  ret void
}

!0 = !{i128 0, i128 3}
!1 = !{}
```

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