[llvm] llvm-reduce: Change exit code for uninteresting inputs (PR #134021)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/134021

This makes it easier to reduce llvm-reduce with llvm-reduce to filter
cases where the input reduced too much.

Not sure if it's possible to test the exit code in lit.

>From 3870f61b08094cfb2f1cade7617180476157c4f5 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Wed, 2 Apr 2025 10:04:35 +0700
Subject: [PATCH] llvm-reduce: Change exit code for uninteresting inputs

This makes it easier to reduce llvm-reduce with llvm-reduce to filter
cases where the input reduced too much.

Not sure if it's possible to test the exit code in lit.
---
 llvm/docs/CommandGuide/llvm-reduce.rst | 5 +++--
 llvm/tools/llvm-reduce/llvm-reduce.cpp | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/llvm/docs/CommandGuide/llvm-reduce.rst b/llvm/docs/CommandGuide/llvm-reduce.rst
index 2670668af6cca..85111e6e29443 100644
--- a/llvm/docs/CommandGuide/llvm-reduce.rst
+++ b/llvm/docs/CommandGuide/llvm-reduce.rst
@@ -108,8 +108,9 @@ GENERIC OPTIONS
 EXIT STATUS
 ------------
 
-:program:`llvm-reduce` returns 0 under normal operation. It returns a non-zero
-exit code if there were any errors.
+:program:`llvm-reduce` returns 0 under normal operation. It returns a
+non-zero exit code if there were any errors. Returns 2 if the
+interestingness test reported the initial input was not interesting.
 
 EXAMPLE
 -------
diff --git a/llvm/tools/llvm-reduce/llvm-reduce.cpp b/llvm/tools/llvm-reduce/llvm-reduce.cpp
index 288a384c2ed49..f7492988084ce 100644
--- a/llvm/tools/llvm-reduce/llvm-reduce.cpp
+++ b/llvm/tools/llvm-reduce/llvm-reduce.cpp
@@ -203,7 +203,7 @@ int main(int Argc, char **Argv) {
   // interestingness checks.
   if (!Tester.getProgram().isReduced(Tester)) {
     errs() << "\nInput isn't interesting! Verify interesting-ness test\n";
-    return 1;
+    return 2;
   }
 
   // Try to reduce code