[clang] [HIP] fix host min/max in header (PR #82956)

[Yaxun Liu via cfe-commits]

https://github.com/yxsamliu created https://github.com/llvm/llvm-project/pull/82956

CUDA defines min/max functions for host in global namespace. HIP header needs to define them too to be compatible. Currently only min/max(int, int) is defined. This causes wrong result for arguments that are out of range for int. This patch defines host min/max functions to be compatible with CUDA.

Fixes: SWDEV-446564

>From e36760486cc794dd3dc1604b0969b83f25bdd757 Mon Sep 17 00:00:00 2001
From: "Yaxun (Sam) Liu" <yaxun.liu at amd.com>
Date: Sun, 25 Feb 2024 11:13:40 -0500
Subject: [PATCH] [HIP] fix host min/max in header

CUDA defines min/max functions for host in global namespace.
HIP header needs to define them too to be compatible.
Currently only min/max(int, int) is defined. This causes
wrong result for arguments that are out of range for int.
This patch defines host min/max functions to be compatible
with CUDA.

Fixes: SWDEV-446564
---
 clang/lib/Headers/__clang_hip_math.h | 48 ++++++++++++++++++++++++----
 1 file changed, 42 insertions(+), 6 deletions(-)

diff --git a/clang/lib/Headers/__clang_hip_math.h b/clang/lib/Headers/__clang_hip_math.h
index 11e1e7d032586f..e87070e41b0ffc 100644
--- a/clang/lib/Headers/__clang_hip_math.h
+++ b/clang/lib/Headers/__clang_hip_math.h
@@ -1306,14 +1306,50 @@ float min(float __x, float __y) { return __builtin_fminf(__x, __y); }
 __DEVICE__
 double min(double __x, double __y) { return __builtin_fmin(__x, __y); }
 
+// Define host min/max functions.
+
 #if !defined(__HIPCC_RTC__) && !defined(__OPENMP_AMDGCN__)
-__host__ inline static int min(int __arg1, int __arg2) {
-  return __arg1 < __arg2 ? __arg1 : __arg2;
-}
 
-__host__ inline static int max(int __arg1, int __arg2) {
-  return __arg1 > __arg2 ? __arg1 : __arg2;
-}
+#pragma push_macro("DEFINE_MIN_MAX_FUNCTIONS")
+#define DEFINE_MIN_MAX_FUNCTIONS(type1, type2) \
+static inline auto min(const type1 __a, const type2 __b) \
+  -> typename std::remove_reference<decltype(__a < __b ? __a : __b)>::type { \
+  return (__a < __b) ? __a : __b; \
+} \
+static inline auto max(const type1 __a, const type2 __b) \
+  -> typename std::remove_reference<decltype(__a > __b ? __a : __b)>::type { \
+  return (__a > __b) ? __a : __b; \
+}
+
+// Define min and max functions for same type comparisons
+DEFINE_MIN_MAX_FUNCTIONS(int, int)
+DEFINE_MIN_MAX_FUNCTIONS(unsigned int, unsigned int)
+DEFINE_MIN_MAX_FUNCTIONS(long, long)
+DEFINE_MIN_MAX_FUNCTIONS(unsigned long, unsigned long)
+DEFINE_MIN_MAX_FUNCTIONS(long long, long long)
+DEFINE_MIN_MAX_FUNCTIONS(unsigned long long, unsigned long long)
+
+// Define min and max functions for mixed type comparisons
+DEFINE_MIN_MAX_FUNCTIONS(int, unsigned int)
+DEFINE_MIN_MAX_FUNCTIONS(unsigned int, int)
+DEFINE_MIN_MAX_FUNCTIONS(long, unsigned long)
+DEFINE_MIN_MAX_FUNCTIONS(unsigned long, long)
+DEFINE_MIN_MAX_FUNCTIONS(long long, unsigned long long)
+DEFINE_MIN_MAX_FUNCTIONS(unsigned long long, long long)
+
+// Floating-point comparisons using built-in functions
+static inline float min(float const __a, float const __b) { return __builtin_fminf(__a, __b); }
+static inline double min(double const __a, double const __b) { return __builtin_fmin(__a, __b); }
+static inline double min(float const __a, double const __b) { return __builtin_fmin(__a, __b); }
+static inline double min(double const __a, float const __b) { return __builtin_fmin(__a, __b); }
+
+static inline float max(float const __a, float const __b) { return __builtin_fmaxf(__a, __b); }
+static inline double max(double const __a, double const __b) { return __builtin_fmax(__a, __b); }
+static inline double max(float const __a, double const __b) { return __builtin_fmax(__a, __b); }
+static inline double max(double const __a, float const __b) { return __builtin_fmax(__a, __b); }
+
+#pragma pop_macro("DEFINE_MIN_MAX_FUNCTIONS")
+
 #endif // !defined(__HIPCC_RTC__) && !defined(__OPENMP_AMDGCN__)
 #endif