2 files changed, 48 insertions, 0 deletions
diff --git a/tests/mir-opt/instcombine_duplicate_switch_targets.assert_zero.InstCombine.diff b/tests/mir-opt/instcombine_duplicate_switch_targets.assert_zero.InstCombine.diff
new file mode 100644
index 00000000000..e04079453d2
--- /dev/null
+++ b/tests/mir-opt/instcombine_duplicate_switch_targets.assert_zero.InstCombine.diff
@@ -0,0 +1,21 @@
+- // MIR for `assert_zero` before InstCombine
++ // MIR for `assert_zero` after InstCombine
+  
+  fn assert_zero(_1: u8) -> u8 {
+      let mut _0: u8;                      // return place in scope 0 at $DIR/instcombine_duplicate_switch_targets.rs:+0:37: +0:39
+  
+      bb0: {
+-         switchInt(_1) -> [0: bb2, 1: bb1, otherwise: bb1]; // scope 0 at $DIR/instcombine_duplicate_switch_targets.rs:+3:13: +7:14
++         switchInt(_1) -> [0: bb2, otherwise: bb1]; // scope 0 at $DIR/instcombine_duplicate_switch_targets.rs:+3:13: +7:14
+      }
+  
+      bb1: {
+          unreachable;                     // scope 0 at $DIR/instcombine_duplicate_switch_targets.rs:+10:13: +10:26
+      }
+  
+      bb2: {
+          _0 = _1;                         // scope 0 at $DIR/instcombine_duplicate_switch_targets.rs:+13:13: +13:20
+          return;                          // scope 0 at $DIR/instcombine_duplicate_switch_targets.rs:+14:13: +14:21
+      }
+  }
+  
diff --git a/tests/mir-opt/instcombine_duplicate_switch_targets.rs b/tests/mir-opt/instcombine_duplicate_switch_targets.rs
new file mode 100644
index 00000000000..ef3b487afa3
--- /dev/null
+++ b/tests/mir-opt/instcombine_duplicate_switch_targets.rs
@@ -0,0 +1,27 @@
+#![feature(custom_mir, core_intrinsics)]
+#![crate_type = "lib"]
+
+use std::intrinsics::mir::*;
+
+// unit-test: InstCombine
+
+// EMIT_MIR instcombine_duplicate_switch_targets.assert_zero.InstCombine.diff
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+pub unsafe fn assert_zero(x: u8) -> u8 {
+    mir!(
+        {
+            match x {
+                0 => retblock,
+                1 => unreachable,
+                _ => unreachable,
+            }
+        }
+        unreachable = {
+            Unreachable()
+        }
+        retblock = {
+            RET = x;
+            Return()
+        }
+    )
+}