test: add GenericMemoryRef address space regression test

Add test case for LLVM IR generation bug where stores to GenericMemoryRef
incorrectly use addrspace(10) instead of addrspace(11) in bounds checking
code, causing assertion failures in LLVM optimization passes.

This reproduces the issue described in the gist where bounds checking
generates incorrect address space casts in the LLVM IR.

Author: rickwoi

test/llvmpasses/memoryref-addrspace.jl

@@ -0,0 +1,21 @@
+# This file is a part of Julia. License is MIT: https://julialang.org/license
+# RUN: julia --startup-file=no --check-bounds=yes %s %t -O
+# RUN: cat %t/* | FileCheck %s
+
+include(joinpath("..", "testhelpers", "llvmpasses.jl"))
+
+# Test for GenericMemoryRef address space bug
+# Issue: stores incorrectly use addrspace(10) instead of addrspace(11)
+# in bounds checking code, causing LLVM assertion failures
+function bf(i, x)
+    x[i] *= x[i]
+    nothing
+end
+
+# CHECK-LABEL: @julia_bf
+# CHECK: oob:
+# CHECK: store {{.*}} addrspace(11) {{.*}}GenericMemoryRef
+# CHECK-NOT: store {{.*}} addrspace(10) {{.*}}GenericMemoryRef
+# CHECK: call void @ijl_bounds_error_int
+
+emit(bf, Tuple{Int, Vector{Float64}})