[flang-commits] [flang] [flang][test] fix sporadically failing test (PR #134608)

[Tom Eccles via flang-commits]

https://github.com/tblah created https://github.com/llvm/llvm-project/pull/134608

The test is checking output from MLIR debug prints. MLIR passes can be executed in parallel, for example a pass on func.func might schedule different func.func operations in different threads. This led to intermittent test failures where debug output from different threads became mixed up.

Fix by disabling mlir multithreading for this test.

>From 8e20466509c7d7707efa1dfae8e7b84225981500 Mon Sep 17 00:00:00 2001
From: Tom Eccles <tom.eccles at arm.com>
Date: Mon, 7 Apr 2025 10:53:30 +0000
Subject: [PATCH] [flang][test] fix sporadically failing test

The test is checking output from MLIR debug prints. MLIR passes can be
executed in parallel, for example a pass on func.func might schedule
different func.func operations in different threads. This led to
intermittent test failures where debug output from different threads
became mixed up.

Fix by disabling mlir multithreading for this test.
---
 flang/test/Transforms/DoConcurrent/loop_nest_test.f90 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/flang/test/Transforms/DoConcurrent/loop_nest_test.f90 b/flang/test/Transforms/DoConcurrent/loop_nest_test.f90
index 0d21b31519728..32bed61fe69e4 100644
--- a/flang/test/Transforms/DoConcurrent/loop_nest_test.f90
+++ b/flang/test/Transforms/DoConcurrent/loop_nest_test.f90
@@ -3,7 +3,7 @@
 ! REQUIRES: asserts
 
 ! RUN: %flang_fc1 -emit-hlfir  -fopenmp -fdo-concurrent-to-openmp=host \
-! RUN:   -mmlir -debug %s -o - 2> %t.log || true
+! RUN:   -mmlir -debug -mmlir -mlir-disable-threading %s -o - 2> %t.log || true
 
 ! RUN: FileCheck %s < %t.log