make switch condition constant folding much more aggressive, handling
compound statements and break statements. This implements enough to
handle PR9322 and rdar://6970405.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126602 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/switch-dce.c b/test/CodeGen/switch-dce.c
index f06a3ed..3276737 100644
--- a/test/CodeGen/switch-dce.c
+++ b/test/CodeGen/switch-dce.c
@@ -1,18 +1,169 @@
// 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: add nsw i32
+// CHECK-NOT: @dead
// CHECK: ret void
+int i;
+void dead();
+
void test1() {
- int i;
switch (1)
case 1:
++i;
switch (0)
case 1:
- i+=2;
+ 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;
+ 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;
+ }
+}
+