[libc-commits] [libc] [libc][math] Skip setting errno and floating point exception for math functions when LIBC_MATH flag has LIBC_MATH_NO_ERRNO and LIBC_MATH_NO_EXCEPT. (PR #144920)

[via libc-commits]

https://github.com/lntue created https://github.com/llvm/llvm-project/pull/144920

None

>From 2b03e4d23cb8b2d00cdd6030125824d414edb4e4 Mon Sep 17 00:00:00 2001
From: Tue Ly <lntue.h at gmail.com>
Date: Thu, 19 Jun 2025 16:11:29 +0000
Subject: [PATCH] [libc][math] Skip setting errno and floating point exception
 for math functions when LIBC_MATH flag has LIBC_MATH_NO_ERRNO and
 LIBC_MATH_NO_EXCEPT.

---
 libc/src/__support/FPUtil/FEnvImpl.h     | 17 +++++++++++++----
 libc/src/__support/macros/optimization.h |  8 ++++++++
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/libc/src/__support/FPUtil/FEnvImpl.h b/libc/src/__support/FPUtil/FEnvImpl.h
index 50a101f833c55..ba145a3da45cc 100644
--- a/libc/src/__support/FPUtil/FEnvImpl.h
+++ b/libc/src/__support/FPUtil/FEnvImpl.h
@@ -15,6 +15,7 @@
 #include "src/__support/libc_errno.h"
 #include "src/__support/macros/attributes.h" // LIBC_INLINE
 #include "src/__support/macros/config.h"
+#include "src/__support/macros/optimization.h"
 #include "src/__support/macros/properties/architectures.h"
 
 #if defined(LIBC_TARGET_ARCH_IS_AARCH64) && defined(__ARM_FP)
@@ -71,27 +72,35 @@ LIBC_INLINE int set_env(const fenv_t *) { return 0; }
 namespace LIBC_NAMESPACE_DECL {
 namespace fputil {
 
-LIBC_INLINE int clear_except_if_required(int excepts) {
+LIBC_INLINE static int clear_except_if_required([[maybe_unused]] int excepts) {
+#ifndef LIBC_MATH_HAS_NO_EXCEPT
   if (math_errhandling & MATH_ERREXCEPT)
     return clear_except(excepts);
+#endif // LIBC_MATH_HAS_NO_EXCEPT
   return 0;
 }
 
-LIBC_INLINE int set_except_if_required(int excepts) {
+LIBC_INLINE static int set_except_if_required([[maybe_unused]] int excepts) {
+#ifndef LIBC_MATH_HAS_NO_EXCEPT
   if (math_errhandling & MATH_ERREXCEPT)
     return set_except(excepts);
+#endif // LIBC_MATH_HAS_NO_EXCEPT
   return 0;
 }
 
-LIBC_INLINE int raise_except_if_required(int excepts) {
+LIBC_INLINE static int raise_except_if_required([[maybe_unused]] int excepts) {
+#ifndef LIBC_MATH_HAS_NO_EXCEPT
   if (math_errhandling & MATH_ERREXCEPT)
     return raise_except(excepts);
+#endif // LIBC_MATH_HAS_NO_EXCEPT
   return 0;
 }
 
-LIBC_INLINE void set_errno_if_required(int err) {
+LIBC_INLINE static void set_errno_if_required([[maybe_unused]] int err) {
+#ifndef LIBC_MATH_HAS_NO_ERRNO
   if (math_errhandling & MATH_ERRNO)
     libc_errno = err;
+#endif // LIBC_MATH_HAS_NO_ERRNO
 }
 
 } // namespace fputil
diff --git a/libc/src/__support/macros/optimization.h b/libc/src/__support/macros/optimization.h
index 253843e5e37aa..db008d323b3a3 100644
--- a/libc/src/__support/macros/optimization.h
+++ b/libc/src/__support/macros/optimization.h
@@ -63,4 +63,12 @@ LIBC_INLINE constexpr bool expects_bool_condition(T value, T expected) {
 #define LIBC_MATH_HAS_INTERMEDIATE_COMP_IN_FLOAT
 #endif
 
+#if (LIBC_MATH & LIBC_MATH_NO_ERRNO)
+#define LIBC_MATH_HAS_NO_ERRNO
+#endif
+
+#if (LIBC_MATH & LIBC_MATH_NO_EXCEPT)
+#define LIBC_MATH_HAS_NO_EXCEPT
+#endif
+
 #endif // LLVM_LIBC_SRC___SUPPORT_MACROS_OPTIMIZATION_H