Update the test case for SimplifyCfg-after-unreachable-enum-branching

tests/mir-opt/simplify_duplicate_unreachable_blocks.assert_nonzero_nonmax.SimplifyCfg-after-unreachable-enum-branching.diff → tests/mir-opt/simplify_dead_blocks.assert_nonzero_nonmax.SimplifyCfg-after-unreachable-enum-branching.diff

@@ -5,19 +5,27 @@
       let mut _0: u8;
 
       bb0: {
--         switchInt(_1) -> [0: bb1, 255: bb2, otherwise: bb3];
-+         switchInt(_1) -> [0: bb1, 255: bb1, otherwise: bb2];
+-         switchInt(_1) -> [0: bb3, 1: bb2, 255: bb3, otherwise: bb4];
++         switchInt(_1) -> [0: bb2, 1: bb1, 255: bb2, otherwise: bb3];
       }
 
       bb1: {
-          unreachable;
-      }
-
-      bb2: {
--         unreachable;
+-         _0 = const 1_u8;
+-         return;
 -     }
 - 
+-     bb2: {
+          _0 = const 2_u8;
+          return;
+      }
+
 -     bb3: {
++     bb2: {
+          unreachable;
+      }
+
+-     bb4: {
++     bb3: {
           _0 = _1;
           return;
       }

tests/mir-opt/simplify_dead_blocks.rs

@@ -0,0 +1,52 @@
+//@ unit-test: SimplifyCfg-after-unreachable-enum-branching
+#![feature(custom_mir, core_intrinsics)]
+#![crate_type = "lib"]
+
+use std::intrinsics::mir::*;
+
+// Check that we correctly cleaned up the dead BB.
+// EMIT_MIR simplify_dead_blocks.assert_nonzero_nonmax.SimplifyCfg-after-unreachable-enum-branching.diff
+#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
+pub unsafe fn assert_nonzero_nonmax(x: u8) -> u8 {
+    // CHECK-LABEL: fn assert_nonzero_nonmax(
+    // CHECK: bb0: {
+    // CHECK-NEXT: switchInt({{.*}}) -> [0: [[unreachable:bb.*]], 1: [[retblock2:bb.*]], 255: [[unreachable:bb.*]], otherwise: [[retblock:bb.*]]];
+    // CHECK-NEXT: }
+    // CHECK-NOT: _0 = const 1_u8;
+    // CHECK: [[retblock2]]: {
+    // CHECK-NEXT: _0 = const 2_u8;
+    // CHECK-NEXT: return;
+    // CHECK-NEXT: }
+    // CHECK: [[unreachable]]: {
+    // CHECK-NEXT: unreachable;
+    // CHECK-NEXT: }
+    // CHECK: [[retblock]]: {
+    // CHECK-NEXT: _0 = _1;
+    // CHECK-NEXT: return;
+    // CHECK-NEXT: }
+    mir!(
+        {
+            match x {
+                0 => unreachable,
+                1 => retblock2,
+                u8::MAX => unreachable,
+                _ => retblock,
+            }
+        }
+        deadRetblock1 = {
+            RET = 1;
+            Return()
+        }
+        retblock2 = {
+            RET = 2;
+            Return()
+        }
+        unreachable = {
+            Unreachable()
+        }
+        retblock = {
+            RET = x;
+            Return()
+        }
+    )
+}