[BasicAA] Add wrapping test for #72831.

Add test with GEP where the index may wrap.

Author: fhahn

llvm/test/Analysis/BasicAA/gep-modulo.ll

@@ -362,4 +362,35 @@ define i8 @mul_nsw_var_nonzero_minabsvarindex_one_index(ptr %arr, i8 %x, i64 %v)
   ret i8 %l
 }
 
+; FIXME: %gep and %p can alias.
+define i8 @test_pr72831_may_wrap(i64 %off) {
+; CHECK-LABEL: Function: test_pr72831_may_wrap: 2 pointers, 0 call sites
+; CHECK-NEXT:  NoAlias:    i8* %gep, i8* %p
+entry:
+  %p = alloca [2 x i8], align 1
+  %ext = zext i1 false to i64
+  %add.1 = add nuw nsw i64 %off, 1
+  %add.2 = add nuw nsw i64 %add.1, %ext
+  %idx = shl i64 %add.2, 32
+  %gep = getelementptr inbounds [2 x i8], ptr %p, i64 0, i64 %idx
+  store i8 0, ptr %gep, align 1
+  %l = load i8, ptr %p, align 1
+  ret i8 %l
+}
+
+define i8 @test_pr72831_no_wrap(i64 %off) {
+; CHECK-LABEL: Function: test_pr72831_no_wrap: 2 pointers, 0 call sites
+; CHECK-NEXT:  NoAlias:    i8* %gep, i8* %p
+entry:
+  %p = alloca [2 x i8], align 1
+  %ext = zext i1 false to i64
+  %add.1 = add nuw nsw i64 %off, 1
+  %add.2 = add nuw nsw i64 %add.1, %ext
+  %idx = shl nsw nuw i64 %add.2, 32
+  %gep = getelementptr inbounds [2 x i8], ptr %p, i64 0, i64 %idx
+  store i8 0, ptr %gep, align 1
+  %l = load i8, ptr %p, align 1
+  ret i8 %l
+}
+
 declare void @llvm.assume(i1)