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From: "Mattias Rönnblom" <mattias.ronnblom@ericsson.com>
To: David Marchand <david.marchand@redhat.com>
Cc: dev@dpdk.org, hofors@lysator.liu.se,
	"Morten Brørup" <mb@smartsharesystems.com>,
	"Luka Jankovic" <luka.jankovic@ericsson.com>,
	"Thomas Monjalon" <thomas@monjalon.net>,
	"Mattias Rönnblom" <mattias.ronnblom@ericsson.com>
Subject: [PATCH] bitops: fix issue in parallel atomic tests
Date: Sun, 13 Oct 2024 13:57:19 +0200	[thread overview]
Message-ID: <20241013115719.820853-1-mattias.ronnblom@ericsson.com> (raw)

The macros generating the parallel test for atomic test-and-
[set|clear|flip] functions used a 64-bit reference word when assuring
no neighbouring bits were modified, even when generating code for the
32-bit version of the test.

This issue causes spurious test failures on GCC 12.2.0 (the default
compiler on for example Debian 12 "bookworm"), when optimization level
2 or higher are used.

The test failures do not occur with GCC 11, 12.3 and 13.2.

To the author, this looks like a promotion-related compiler bug in GCC
12.2.

Fixes: 35326b61aecb ("bitops: add atomic bit operations in new API")

Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
---
 app/test/test_bitops.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/app/test/test_bitops.c b/app/test/test_bitops.c
index 4200073ae4..681e984037 100644
--- a/app/test/test_bitops.c
+++ b/app/test/test_bitops.c
@@ -227,7 +227,7 @@ test_bit_atomic_parallel_test_and_modify ## size(void) \
 	bool expected_value = total_flips % 2; \
 	TEST_ASSERT(expected_value == rte_bit_test(&word, bit), \
 		"After %"PRId64" flips, the bit value should be %d", total_flips, expected_value); \
-	uint64_t expected_word = 0; \
+	uint ## size ## _t expected_word = 0; \
 	rte_bit_assign(&expected_word, bit, expected_value); \
 	TEST_ASSERT(expected_word == word, "Untouched bits have changed value"); \
 	return TEST_SUCCESS; \
@@ -275,7 +275,7 @@ test_bit_atomic_parallel_flip ## size(void) \
 	bool expected_value = total_flips % 2; \
 	TEST_ASSERT(expected_value == rte_bit_test(&word, bit), \
 		"After %"PRId64" flips, the bit value should be %d", total_flips, expected_value); \
-	uint64_t expected_word = 0; \
+	uint ## size ## _t expected_word = 0; \
 	rte_bit_assign(&expected_word, bit, expected_value); \
 	TEST_ASSERT(expected_word == word, "Untouched bits have changed value"); \
 	return TEST_SUCCESS; \
-- 
2.43.0


             reply	other threads:[~2024-10-13 12:06 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-13 11:57 Mattias Rönnblom [this message]
2024-10-13 13:37 ` Morten Brørup
2024-10-13 15:19   ` Mattias Rönnblom
2024-10-13 15:36     ` Morten Brørup
2024-10-14 14:16       ` David Marchand
2024-10-14 14:33         ` Mattias Rönnblom
2024-10-14 14:14 ` David Marchand

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