[libc-commits] [libc] [libc][math] Fix arm-linux-gnueabihf target when building with gcc/g++. (PR #202090)

[via libc-commits]

https://github.com/lntue created https://github.com/llvm/llvm-project/pull/202090

- Default arm-linux-gnueabihf-gcc defines fixed point macros (like `__FRACT_FBIT__`) but does not support `_Fract` and `_Accum` types by default.  We just limit the fixed point support to clang for now.
- Specify the types for the sqrt instructions we use for ARM target.

Fixes https://github.com/llvm/llvm-project/issues/201678.


>From 6435acd82801bd8ea3e7f6a6a3931a1f4d600864 Mon Sep 17 00:00:00 2001
From: Tue Ly <lntue.h at gmail.com>
Date: Sat, 6 Jun 2026 22:12:35 +0000
Subject: [PATCH] [libc][math] Fix arm-linux-gnueabihf target when building
 with gcc/g++.

---
 libc/include/llvm-libc-macros/stdfix-macros.h | 2 +-
 libc/src/__support/FPUtil/arm/sqrt.h          | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/libc/include/llvm-libc-macros/stdfix-macros.h b/libc/include/llvm-libc-macros/stdfix-macros.h
index 04097e14e9747..20fa41e509e58 100644
--- a/libc/include/llvm-libc-macros/stdfix-macros.h
+++ b/libc/include/llvm-libc-macros/stdfix-macros.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_MACROS_STDFIX_MACROS_H
 #define LLVM_LIBC_MACROS_STDFIX_MACROS_H
 
-#ifdef __FRACT_FBIT__
+#if defined(__FRACT_FBIT__) && defined(__clang__)
 // _Fract and _Accum types are available
 #define LIBC_COMPILER_HAS_FIXED_POINT
 #endif // __FRACT_FBIT__
diff --git a/libc/src/__support/FPUtil/arm/sqrt.h b/libc/src/__support/FPUtil/arm/sqrt.h
index e6cb58c0be817..71803c2ad3156 100644
--- a/libc/src/__support/FPUtil/arm/sqrt.h
+++ b/libc/src/__support/FPUtil/arm/sqrt.h
@@ -26,7 +26,7 @@ namespace fputil {
 #ifdef LIBC_TARGET_CPU_HAS_FPU_FLOAT
 template <> LIBC_INLINE float sqrt<float>(float x) {
   float y;
-  asm("vsqrt %0, %1\n\t" : "=w"(y) : "w"(x));
+  asm("vsqrt.f32 %0, %1\n\t" : "=w"(y) : "w"(x));
   return y;
 }
 #endif // LIBC_TARGET_CPU_HAS_FPU_FLOAT
@@ -34,7 +34,7 @@ template <> LIBC_INLINE float sqrt<float>(float x) {
 #ifdef LIBC_TARGET_CPU_HAS_FPU_DOUBLE
 template <> LIBC_INLINE double sqrt<double>(double x) {
   double y;
-  asm("vsqrt %0, %1\n\t" : "=w"(y) : "w"(x));
+  asm("vsqrt.f64 %P0, %P1\n\t" : "=w"(y) : "w"(x));
   return y;
 }
 #endif // LIBC_TARGET_CPU_HAS_FPU_DOUBLE