[libcxx-commits] [libcxx] [libc++][test] Make macro detection more friendly to MSVC (PR #113633)

[A. Jiang via libcxx-commits]

https://github.com/frederick-vs-ja created https://github.com/llvm/llvm-project/pull/113633

MSVC's test suite is a bit nervous about replacing non-macro-defined identifiers with `0` (see also https://learn.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-4-c4668?view=msvc-170).

On MSVC (and MS-compatible mode of other compilers), `long double` has the same format (IEEE-754 binary64) as  `double`, so it should be OK to define `TEST_LONG_DOUBLE_IS_DOUBLE` when `_MSC_VER` is defined. Such detection should be performed first.

>From c04730ff3aa2f755b0286be8b1e1424c386a2e8e Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34 at live.cn>
Date: Fri, 25 Oct 2024 10:17:55 +0800
Subject: [PATCH] [libc++][test] Make macro detection more friendly to MSVC

MSVC's test suite is a bit nervous about replacing non-macro-defined identifiers with `0` (see also https://learn.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-4-c4668?view=msvc-170).

On MSVC (and MS-compatible mode of other compilers), `long double` has the same format (IEEE-754 binary64) as  `double`, so it should be OK to define `TEST_LONG_DOUBLE_IS_DOUBLE` when `_MSC_VER` is defined. Such detection should be performed first.
---
 libcxx/test/support/test_macros.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libcxx/test/support/test_macros.h b/libcxx/test/support/test_macros.h
index 5ef14e54dae237..1b6473b623c53b 100644
--- a/libcxx/test/support/test_macros.h
+++ b/libcxx/test/support/test_macros.h
@@ -511,7 +511,7 @@ inline Tp const& DoNotOptimize(Tp const& value) {
 #  define TEST_CONSTEXPR_OPERATOR_NEW
 #endif
 
-#if __SIZEOF_LONG_DOUBLE__ == __SIZEOF_DOUBLE__
+#if defined(_MSC_VER) || __SIZEOF_LONG_DOUBLE__ == __SIZEOF_DOUBLE__
 #  define TEST_LONG_DOUBLE_IS_DOUBLE
 #endif