--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/CodeGen/switch.c	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,213 @@
+// RUN: %clang_cc1 -triple i386-unknown-unknown -O3 %s -emit-llvm -o - | FileCheck %s
+
+int foo(int i) {
+  int j = 0;
+  switch (i) {
+  case -1:
+    j = 1; break;
+  case 1 :
+    j = 2; break;
+  case 2:
+    j = 3; break;
+  default:
+    j = 42; break;
+  }
+  j = j + 1;
+  return j;
+}
+
+int foo2(int i) {
+  int j = 0;
+  switch (i) {
+  case 1 :
+    j = 2; break;
+  case 2 ... 10:
+    j = 3; break;
+  default:
+    j = 42; break;
+  }
+  j = j + 1;
+  return j;
+}
+
+int foo3(int i) {
+  int j = 0;
+  switch (i) {
+  default:
+    j = 42; break;
+  case 111:
+    j = 111; break;
+  case 0 ... 100:
+    j = 1; break;
+  case 222:
+    j = 222; break;
+  }
+  return j;
+}
+
+
+static int foo4(int i) {
+  int j = 0;
+  switch (i) {
+  case 111:
+    j = 111; break;
+  case 0 ... 100:
+    j = 1; break;
+  case 222:
+    j = 222; break;
+  default:
+    j = 42; break;
+  case 501 ... 600:
+    j = 5; break;
+  }
+  return j;
+}
+
+// CHECK-LABEL: define i32 @foo4t()
+// CHECK: ret i32 376
+// CHECK: }
+int foo4t() {
+  // 111 + 1 + 222 + 42 = 376
+  return foo4(111) + foo4(99) + foo4(222) + foo4(601);
+}
+
+// CHECK-LABEL: define void @foo5()
+// CHECK-NOT: switch
+// CHECK: }
+void foo5(){
+    switch(0){
+    default:
+        if (0) {
+
+        }
+    }
+}
+
+// CHECK-LABEL: define void @foo6()
+// CHECK-NOT: switch
+// CHECK: }
+void foo6(){
+    switch(0){
+    }
+}
+
+// CHECK-LABEL: define void @foo7()
+// CHECK-NOT: switch
+// CHECK: }
+void foo7(){
+    switch(0){
+      foo7();
+    }
+}
+
+
+// CHECK-LABEL: define i32 @f8(
+// CHECK: ret i32 3
+// CHECK: }
+int f8(unsigned x) {
+  switch(x) {
+  default:
+    return 3;
+  case 0xFFFFFFFF ... 1: // This range should be empty because x is unsigned.
+    return 0;
+  }
+}
+
+// Ensure that default after a case range is not ignored.
+//
+// CHECK-LABEL: define i32 @f9()
+// CHECK: ret i32 10
+// CHECK: }
+static int f9_0(unsigned x) {
+  switch(x) {
+  case 10 ... 0xFFFFFFFF:
+    return 0;
+  default:
+    return 10;
+  }
+}
+int f9() {
+  return f9_0(2);
+}
+
+// Ensure that this doesn't compile to infinite loop in g() due to
+// miscompilation of fallthrough from default to a (tested) case
+// range.
+//
+// CHECK-LABEL: define i32 @f10()
+// CHECK: ret i32 10
+// CHECK: }
+static int f10_0(unsigned x) {
+  switch(x) {
+  default:
+    x += 1;
+  case 10 ... 0xFFFFFFFF:
+    return 0;
+  }
+}
+
+int f10() {
+  f10_0(1);
+  return 10;
+}
+
+// This generated incorrect code because of poor switch chaining.
+//
+// CHECK-LABEL: define i32 @f11(
+// CHECK: ret i32 3
+// CHECK: }
+int f11(int x) {
+  switch(x) {
+  default:
+    return 3;
+  case 10 ... 0xFFFFFFFF:
+    return 0;
+  }
+}
+
+// This just asserted because of the way case ranges were calculated.
+//
+// CHECK-LABEL: define i32 @f12(
+// CHECK: ret i32 3
+// CHECK: }
+int f12(int x) {
+  switch (x) {
+  default:
+    return 3;
+  case 10 ... -1: 
+    return 0;
+  }
+}
+
+// Make sure return is not constant (if empty range is skipped or miscompiled)
+//
+// CHECK-LABEL: define i32 @f13(
+// CHECK: ret i32 %
+// CHECK: }
+int f13(unsigned x) {
+  switch(x) {
+  case 2:
+    // fallthrough empty range
+  case 10 ... 9:
+    return 10;
+  default:
+    return 0;
+  }
+}
+
+// Don't delete a basic block that we want to introduce later references to.
+// This isn't really specific to switches, but it's easy to show with them.
+// rdar://problem/8837067
+int f14(int x) {
+  switch (x) {
+
+  // case range so that the case block has no predecessors
+  case 0 ... 15:
+    // any expression which doesn't introduce a new block
+    (void) 0;
+    // kaboom
+
+  default:
+    return x;
+  }
+}