update_test_checks: add new test

This test is meant to demonstrate an upcoming change that replaces basic
block labels by FileCheck patterns.

Author: nhaehnle

llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/phi-labels.ll

@@ -0,0 +1,39 @@
+; RUN: opt < %s -S | FileCheck %s
+
+define i32 @phi_after_label(i1 %cc) {
+entry:
+  br i1 %cc, label %then, label %end
+
+then:
+  br label %end
+
+end:
+  %r = phi i32 [ 0, %entry ], [ 1, %then ]
+  ret i32 %r
+}
+
+define void @phi_before_label(i32 %bound) {
+entry:
+  br label %loop
+
+loop:
+  %ctr = phi i32 [ 0, %entry ], [ %ctr.next, %loop ]
+  %ctr.next = add i32 %ctr, 1
+  %cc = icmp ult i32 %ctr.next, %bound
+  br i1 %cc, label %loop, label %end
+
+end:
+  ret void
+}
+
+define i32 @phi_after_label_unnamed(i1 %cc) {
+0:
+  br i1 %cc, label %1, label %2
+
+1:
+  br label %2
+
+2:
+  %r = phi i32 [ 0, %0 ], [ 1, %1 ]
+  ret i32 %r
+}

llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/phi-labels.ll.expected

@@ -0,0 +1,71 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt < %s -S | FileCheck %s
+
+define i32 @phi_after_label(i1 %cc) {
+; CHECK-LABEL: define i32 @phi_after_label(
+; CHECK-SAME: i1 [[CC:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 [[CC]], label [[THEN:%.*]], label [[END:%.*]]
+; CHECK:       then:
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    [[R:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ 1, [[THEN]] ]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+entry:
+  br i1 %cc, label %then, label %end
+
+then:
+  br label %end
+
+end:
+  %r = phi i32 [ 0, %entry ], [ 1, %then ]
+  ret i32 %r
+}
+
+define void @phi_before_label(i32 %bound) {
+; CHECK-LABEL: define void @phi_before_label(
+; CHECK-SAME: i32 [[BOUND:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[CTR:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[CTR_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[CTR_NEXT]] = add i32 [[CTR]], 1
+; CHECK-NEXT:    [[CC:%.*]] = icmp ult i32 [[CTR_NEXT]], [[BOUND]]
+; CHECK-NEXT:    br i1 [[CC]], label [[LOOP]], label [[END:%.*]]
+; CHECK:       end:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %loop
+
+loop:
+  %ctr = phi i32 [ 0, %entry ], [ %ctr.next, %loop ]
+  %ctr.next = add i32 %ctr, 1
+  %cc = icmp ult i32 %ctr.next, %bound
+  br i1 %cc, label %loop, label %end
+
+end:
+  ret void
+}
+
+define i32 @phi_after_label_unnamed(i1 %cc) {
+; CHECK-LABEL: define i32 @phi_after_label_unnamed(
+; CHECK-SAME: i1 [[CC:%.*]]) {
+; CHECK-NEXT:    br i1 [[CC]], label [[TMP1:%.*]], label [[TMP2:%.*]]
+; CHECK:       1:
+; CHECK-NEXT:    br label [[TMP2]]
+; CHECK:       2:
+; CHECK-NEXT:    [[R:%.*]] = phi i32 [ 0, [[TMP0:%.*]] ], [ 1, [[TMP1]] ]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+0:
+  br i1 %cc, label %1, label %2
+
+1:
+  br label %2
+
+2:
+  %r = phi i32 [ 0, %0 ], [ 1, %1 ]
+  ret i32 %r
+}

llvm/test/tools/UpdateTestChecks/update_test_checks/phi-labels.test

@@ -0,0 +1,5 @@
+# RUN: cp -f %S/Inputs/phi-labels.ll %t.ll && %update_test_checks --version 4 %t.ll
+# RUN: diff -u %t.ll %S/Inputs/phi-labels.ll.expected
+## Check that running the script again does not change the result:
+# RUN: %update_test_checks %t.ll
+# RUN: diff -u %t.ll %S/Inputs/phi-labels.ll.expected