[UTC] Precommit testcase for function definition line-splitting

Review of the actual change: https://reviews.llvm.org/D158497

Author: jasilvanus

llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/named_function_arguments_split.ll

@@ -0,0 +1,11 @@
+; Check that we split named function arguments correctly into a separate CHECK line,
+; ensuring the opening parenthesis is on the label name, avoiding incorrect label
+; matches if function names are not prefix free.
+; Note: This is a precommitted test, the current result is incorrect.
+;
+; RUN: opt < %s -passes=instsimplify -S | FileCheck %s
+;
+define i32 @"foo"(i32 %named) {
+entry:
+  ret i32 %named
+}

llvm/test/tools/UpdateTestChecks/update_test_checks/Inputs/named_function_arguments_split.ll.expected

@@ -0,0 +1,17 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; Check that we split named function arguments correctly into a separate CHECK line,
+; ensuring the opening parenthesis is on the label name, avoiding incorrect label
+; matches if function names are not prefix free.
+; Note: This is a precommitted test, the current result is incorrect.
+;
+; RUN: opt < %s -passes=instsimplify -S | FileCheck %s
+;
+define i32 @"foo"(i32 %named) {
+; CHECK-LABEL: define i32 @foo
+; CHECK-SAME: (i32 [[NAMED:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret i32 [[NAMED]]
+;
+entry:
+  ret i32 %named
+}

llvm/test/tools/UpdateTestChecks/update_test_checks/named_function_arguments_split.test

@@ -0,0 +1,7 @@
+# REQUIRES: x86-registered-target
+## Basic test checking that update_test_checks.py works correctly
+# RUN: cp -f %S/Inputs/named_function_arguments_split.ll %t.ll && %update_test_checks %t.ll --version=2
+# RUN: diff -u %t.ll %S/Inputs/named_function_arguments_split.ll.expected
+## Check that running the script again does not change the result:
+# RUN: %update_test_checks %t.ll --version=2
+# RUN: diff -u %t.ll %S/Inputs/named_function_arguments_split.ll.expected