[llvm] [FileCheck] Create test to highlight the "more than 9 back-references" issue. (PR #173501)

[Thomas Symalla via llvm-commits]

https://github.com/tsymalla updated https://github.com/llvm/llvm-project/pull/173501

>From edb2e219b44e84a5ab4a65ed6e9fde58ec78f47f Mon Sep 17 00:00:00 2001
From: Thomas Symalla <github at thomassymalla.de>
Date: Wed, 24 Dec 2025 18:58:43 +0100
Subject: [PATCH] =?UTF-8?q?[FileCheck]=C2=A0Create=20test=20to=20highlight?=
 =?UTF-8?q?=20the=20"more=20than=209=20back-reference"=20issue.?=
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When back-referencing more than 9 variables in a CHECK line, FileCheck will
fail.
---
 llvm/test/FileCheck/capture-limit.txt | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100644 llvm/test/FileCheck/capture-limit.txt

diff --git a/llvm/test/FileCheck/capture-limit.txt b/llvm/test/FileCheck/capture-limit.txt
new file mode 100644
index 0000000000000..9bf2841edb006
--- /dev/null
+++ b/llvm/test/FileCheck/capture-limit.txt
@@ -0,0 +1,7 @@
+; RUN: not FileCheck -input-file %s %s
+
+; Trying to back-reference more than 9 variables is intended to fail.
+
+r0 r1 r2 r3 r4 r5 r6 r7 r8 r9 r9
+
+; CHECK: [[REG1:r0]] [[REG2:r1]] [[REG3:r2]] [[REG4:r3]] [[REG5:r4]] [[REG6:r5]] [[REG7:r6]] [[REG8:r7]] [[REG9:r8]] [[REG10:r9]] [[REG10]]