1 files changed, 35 insertions, 0 deletions

diff --git a/tests/codegen/issues/issue-37945.rs b/tests/codegen/issues/issue-37945.rs
new file mode 100644
index 000000000..4f386d335
--- /dev/null
+++ b/tests/codegen/issues/issue-37945.rs
@@ -0,0 +1,35 @@
+// compile-flags: -O -Zmerge-functions=disabled
+// ignore-32bit LLVM has a bug with them
+// ignore-debug
+
+// Check that LLVM understands that `Iter` pointer is not null. Issue #37945.
+
+#![crate_type = "lib"]
+
+use std::slice::Iter;
+
+#[no_mangle]
+pub fn is_empty_1(xs: Iter<f32>) -> bool {
+// CHECK-LABEL: @is_empty_1(
+// CHECK-NEXT:  start:
+// CHECK-NEXT:    [[A:%.*]] = icmp ne {{i32\*|ptr}} {{%xs.0|%xs.1}}, null
+// CHECK-NEXT:    tail call void @llvm.assume(i1 [[A]])
+// The order between %xs.0 and %xs.1 on the next line doesn't matter
+// and different LLVM versions produce different order.
+// CHECK-NEXT:    [[B:%.*]] = icmp eq {{i32\*|ptr}} {{%xs.0, %xs.1|%xs.1, %xs.0}}
+// CHECK-NEXT:    ret i1 [[B:%.*]]
+    {xs}.next().is_none()
+}
+
+#[no_mangle]
+pub fn is_empty_2(xs: Iter<f32>) -> bool {
+// CHECK-LABEL: @is_empty_2
+// CHECK-NEXT:  start:
+// CHECK-NEXT:    [[C:%.*]] = icmp ne {{i32\*|ptr}} {{%xs.0|%xs.1}}, null
+// CHECK-NEXT:    tail call void @llvm.assume(i1 [[C]])
+// The order between %xs.0 and %xs.1 on the next line doesn't matter
+// and different LLVM versions produce different order.
+// CHECK-NEXT:    [[D:%.*]] = icmp eq {{i32\*|ptr}} {{%xs.0, %xs.1|%xs.1, %xs.0}}
+// CHECK-NEXT:    ret i1 [[D:%.*]]
+    xs.map(|&x| x).next().is_none()
+}