src/test/codegen/issue-77812.rs

   1 // min-llvm-version: 12.0.0
   2 // compile-flags: -O
   3 #![crate_type = "lib"]
   4
   5 // Test that LLVM can eliminate the unreachable `Variant::Zero` branch.
   6
   7 #[derive(Copy, Clone, Eq, PartialEq)]
   8 pub enum Variant {
   9     Zero,
  10     One,
  11     Two,
  12 }
  13
  14 extern {
  15     fn exf1();
  16     fn exf2();
  17 }
  18
  19 pub static mut GLOBAL: Variant = Variant::Zero;
  20
  21 // CHECK-LABEL: @issue_77812
  22 #[no_mangle]
  23 pub unsafe fn issue_77812() {
  24     let g = GLOBAL;
  25     if g != Variant::Zero {
  26         match g {
  27             Variant::One => exf1(),
  28             Variant::Two => exf2(),
  29             // CHECK-NOT: panic
  30             Variant::Zero => panic!(),
  31         }
  32     }
  33 }