Add some tests for SimplifyCFG's ConstantFoldTerminator(). NFC.

llvm-svn: 223395

llvm/test/Transforms/SimplifyCFG/switch-to-br.ll

@@ -0,0 +1,64 @@
+; RUN: opt %s -simplifycfg -S | FileCheck %s
+
+declare i32 @f(i32)
+
+define i32 @basic(i32 %x) {
+; CHECK-LABEL: @basic
+; CHECK-LABEL: entry:
+; CHECK-NEXT:  call i32 @f(i32 0)
+; CHECK-NEXT:  ret i32 %0
+
+entry:
+  switch i32 %x, label %default [
+    i32 5, label %default
+    i32 6, label %default
+    i32 7, label %default
+  ]
+default:
+  %0 = call i32 @f(i32 0)
+  ret i32 %0
+}
+
+
+define i32 @constant() {
+; CHECK-LABEL: @constant
+; CHECK-LABEL: entry:
+; CHECK-NEXT:  call i32 @f(i32 1)
+; CHECK-NEXT:  ret i32 %0
+
+entry:
+  switch i32 42, label %default [
+    i32 41, label %default
+    i32 42, label %a
+    i32 43, label %b
+  ]
+default:
+  %0 = call i32 @f(i32 0)
+  ret i32 %0
+a:
+  %1 = call i32 @f(i32 1)
+  ret i32 %1
+b:
+  %2 = call i32 @f(i32 2)
+  ret i32 %2
+}
+
+
+define i32 @unreachable(i32 %x) {
+; CHECK-LABEL: @unreachable
+; CHECK-LABEL: entry:
+; CHECK-NEXT:  call i32 @f(i32 0)
+; CHECK-NEXT:  ret i32 %0
+
+entry:
+  switch i32 %x, label %unreachable [
+    i32 5, label %a
+    i32 6, label %a
+    i32 7, label %a
+  ]
+unreachable:
+  unreachable
+a:
+  %0 = call i32 @f(i32 0)
+  ret i32 %0
+}