From f77923ef6e810ce780dda1f2d18547350f52171e Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Wed, 29 Apr 2026 11:51:17 -0700
Subject: [PATCH] `P0811R3_midpoint_lerp`: Avoid flaky ARM64 failures

---
 tests/std/tests/P0811R3_midpoint_lerp/test.cpp | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/tests/std/tests/P0811R3_midpoint_lerp/test.cpp b/tests/std/tests/P0811R3_midpoint_lerp/test.cpp
index ff80430f4fb..dd27188f1f7 100644
--- a/tests/std/tests/P0811R3_midpoint_lerp/test.cpp
+++ b/tests/std/tests/P0811R3_midpoint_lerp/test.cpp
@@ -89,8 +89,13 @@ constexpr int fe_overflow = FE_OVERFLOW;
 // "major" floating point exceptions, excluding underflow and inexact
 constexpr int fe_major_except = FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW;
 
-bool check_feexcept(const int expected_excepts, const int except_mask = fe_major_except) {
+bool check_feexcept(
+    [[maybe_unused]] const int expected_excepts, [[maybe_unused]] const int except_mask = fe_major_except) {
+#if defined(_M_ARM64) || defined(_M_ARM64EC) // TRANSITION, GH-5685
+    return true;
+#else // ^^^ workaround / no workaround vvv
     return fetestexcept(except_mask) == (expected_excepts & except_mask);
+#endif // ^^^ no workaround ^^^
 }
 #else // ^^^ defined(_M_FP_STRICT) / !defined(_M_FP_STRICT) vvv
 class ExceptGuard {
@@ -1049,9 +1054,7 @@ void test_gh_1917() {
         ExceptGuard except;
 
         assert(bit_cast<float_bit_type>(lerp(2e+38f, 1e+38f, 4.0f)) == bit_cast<float_bit_type>(-2e+38f));
-#if !defined(_M_ARM64) && !defined(_M_ARM64EC) // TRANSITION, GH-5685
         assert(check_feexcept(0));
-#endif // ^^^ no workaround ^^^
     }
 #ifdef _M_FP_STRICT
     {
@@ -1066,9 +1069,7 @@ void test_gh_1917() {
         RoundGuard round{FE_UPWARD};
 
         assert(bit_cast<float_bit_type>(lerp(2e+38f, 1e+38f, 4.0f)) == bit_cast<float_bit_type>(-2e+38f));
-#if !defined(_M_ARM64) && !defined(_M_ARM64EC) // TRANSITION, GH-5685
         assert(check_feexcept(0));
-#endif // ^^^ no workaround ^^^
     }
     {
         ExceptGuard except;
@@ -1082,9 +1083,7 @@ void test_gh_1917() {
         RoundGuard round{FE_DOWNWARD};
 
         assert(bit_cast<float_bit_type>(lerp(2e+38f, 1e+38f, 4.0f)) == bit_cast<float_bit_type>(-2e+38f));
-#if !defined(_M_ARM64) && !defined(_M_ARM64EC) // TRANSITION, GH-5685
         assert(check_feexcept(0));
-#endif // ^^^ no workaround ^^^
     }
     {
         ExceptGuard except;
@@ -1098,9 +1097,7 @@ void test_gh_1917() {
         RoundGuard round{FE_TOWARDZERO};
 
         assert(bit_cast<float_bit_type>(lerp(2e+38f, 1e+38f, 4.0f)) == bit_cast<float_bit_type>(-2e+38f));
-#if !defined(_M_ARM64) && !defined(_M_ARM64EC) // TRANSITION, GH-5685
         assert(check_feexcept(0));
-#endif // ^^^ no workaround ^^^
     }
     {
         ExceptGuard except;