Add a Few Codegen Tests

Author: veera-sivarajan

tests/codegen/issues/issue-64219.rs

@@ -0,0 +1,19 @@
+//! Test for https://github.com/rust-lang/rust/issues/64219
+//! Check if `noreturn` attribute is applied on calls to
+//! function pointers returning `!` (never type).
+
+#![crate_type = "lib"]
+
+extern "C" {
+    static FOO: fn() -> !;
+}
+
+// CHECK-LABEL: @foo
+#[no_mangle]
+pub unsafe fn foo() {
+    // CHECK: call
+    // CHECK-SAME: [[NUM:#[0-9]+$]]
+    FOO();
+}
+
+// CHECK: attributes [[NUM]] = {{{.*}} noreturn {{.*}}}

tests/codegen/issues/issue-86109.rs

@@ -0,0 +1,25 @@
+//@ compile-flags: -O
+//! Test for https://github.com/rust-lang/rust/issues/86109
+//! Check LLVM can eliminate the impossible division by zero check by
+//! ensuring there is no call (to panic) instruction.
+
+#![crate_type = "lib"]
+
+type T = i16;
+
+// CHECK-LABEL: @foo
+#[no_mangle]
+pub fn foo(start: T) -> T {
+    // CHECK-NOT: call
+    // CHECK: ret
+    if start <= 0 {
+        return 0;
+    }
+    let mut count = 0;
+    for i in start..10_000 {
+        if 752 % i != 0 {
+            count += 1;
+        }
+    }
+    count
+}