[ScopedNoAliasAA] Should ScopedNoAliasAA be more conservative in getting ModRef?

[DianQK]

This IR is reduced from rust-lang/rust#116976.

declare void @use(i64)

define i64 @foo(ptr noalias nocapture noundef align 8 dereferenceable(24) %p) {
  %p1 = getelementptr inbounds i8, ptr %p, i64 16
  %v1 = load i64, ptr %p1, align 8
  call void @use(i64 %v1)
  %p2 = getelementptr inbounds i8, ptr %p, i64 8
  call void @llvm.memset.p0.i64(ptr noundef nonnull align 8 dereferenceable(16) %p2, i8 0, i64 16, i1 false), !alias.scope !0
  %v2 = load i64, ptr %p1, align 8, !noalias !0
  ret i64 %v2
}

; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: write)
declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg) #0

attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: write) }

!0 = !{!1}
!1 = distinct !{!1, !2}
!2 = distinct !{!2}

godbolt: https://llvm.godbolt.org/z/7sTrhYdMo

Currently, GVN replaces %v2 with %v1.
Maybe I'm missing something here. Other passes may have provided incorrect alias information.

From the LLVM Alias Analysis Infrastructure, my understanding is that the alias method returns alias when two memory objects alias each other. And the getModRefInfo returns ModRef when an/any alias exists.

[DianQK]

This is not a source of error.