1 files changed, 234 insertions, 0 deletions
diff --git a/clang/test/CodeGen/switch-dce.c b/clang/test/CodeGen/switch-dce.c
new file mode 100644
index 0000000..a18d3bc
--- /dev/null
+++ b/clang/test/CodeGen/switch-dce.c
@@ -0,0 +1,234 @@
+// RUN: %clang_cc1 -triple i386-unknown-unknown -O0 %s -emit-llvm -o - | FileCheck %s
+
+// PR9322 and rdar://6970405
+
+// CHECK: @test1
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: add nsw i32 {{.*}}, 1
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: ret void
+int i;
+void dead();
+
+void test1() {
+  switch (1)
+    case 1:
+      ++i;
+
+  switch (0)
+    case 1:
+      dead();
+} 
+
+
+// CHECK: @test2
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: add nsw i32 {{.*}}, 2
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: ret void
+void test2() {
+  switch (4) {
+  case 1:
+    dead();
+    break;
+  case 4:
+    i += 2;
+    // Fall off the end of the switch.
+  } 
+}
+
+
+// CHECK: @test3
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: add nsw i32 {{.*}}, 2
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: ret void
+void test3() {
+  switch (4) {
+  case 1:
+    dead();
+    break;
+  case 4: {
+    i += 2;
+    break;
+  }
+  } 
+}
+
+// CHECK: @test4
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: add nsw i32 {{.*}}, 2
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: ret void
+void test4() {
+  switch (4) {
+    case 1:
+      dead();
+      break;
+    default: {
+      i += 2;
+      break;
+    }
+  } 
+}
+
+// This shouldn't crash codegen, but we don't have to optimize out the switch
+// in this case.
+void test5() {
+  switch (1) {
+    int x;  // eliding var decl?
+    case 1:
+      x = 4;
+      i = x;
+      break;
+  } 
+}
+
+// CHECK: @test6
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: ret void
+void test6() {
+  // Neither case is reachable.
+  switch (40) {
+  case 1:
+   dead();
+    break;
+  case 4: {
+    dead();
+    break;
+  }
+  } 
+}
+
+// CHECK: @test7
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: add nsw i32
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: ret void
+void test7() {
+  switch (4) {
+  case 1:
+      dead();
+    break;
+    {
+      case 4:   // crazy brace scenario
+        ++i;
+    }
+    break;
+  } 
+}
+
+// CHECK: @test8
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: add nsw i32
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: ret void
+void test8() {
+  switch (4) {
+  case 1:
+    dead();
+    break;
+  case 4:
+    ++i;
+    // Fall off the end of the switch.
+  } 
+}
+
+// CHECK: @test9
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: add nsw i32
+// CHECK: add nsw i32
+// CHECK-NOT: switch
+// CHECK-NOT: @dead
+// CHECK: ret void
+void test9(int i) {
+  switch (1) {
+  case 5:
+    dead();
+  case 1:
+    ++i;
+    // Fall through is fine.
+  case 4:
+    ++i;
+    break;
+  } 
+}
+
+// CHECK: @test10
+// CHECK-NOT: switch
+// CHECK: ret i32
+int test10(void) {
+	switch(8) {
+		case 8:
+			break;
+		case 4:
+			break;
+		default:
+			dead();
+	}
+	
+	return 0;
+}
+
+// CHECK: @test11
+// CHECK-NOT: switch
+// CHECK: ret void
+void test11() {
+  switch (1) {
+    case 1:
+      break;
+    case 42: ;
+      int x;  // eliding var decl?
+      x = 4;
+      break;
+  }
+}
+
+// CHECK: @test12
+// CHECK-NOT: switch
+// CHECK: ret void
+void test12() {
+  switch (1) {
+  case 2: {
+     int a;   // Ok to skip this vardecl.
+     a = 42;
+   }
+  case 1:
+    break;
+  case 42: ;
+    int x;  // eliding var decl?
+    x = 4;
+    break;
+  }
+}
+
+// Verify that case 42 only calls test14 once.
+// CHECK: @test13
+// CHECK: call void @test13(i32 97)
+// CHECK-NEXT: br label %[[EPILOG2:[0-9.a-z]+]]
+// CHECK: [[EPILOG2]]
+// CHECK-NEXT: br label [[EPILOG:%[0-9.a-z]+]]
+// CHECK: call void @test13(i32 42)
+// CHECK-NEXT: br label [[EPILOG]]
+void test13(int x) {
+  switch (x) {
+    case 42: test13(97);  // fallthrough
+    case 11: break;
+    default: test13(42); break;
+  }
+}
+