From 253c097d5941f006da966a0a84eb8e2694e088df Mon Sep 17 00:00:00 2001
From: Reid Kleckner <reid@kleckner.net>
Date: Wed, 3 Dec 2014 23:36:14 +0000
Subject: [PATCH] Implement __umulh with __int128 arithmetic
Use the same approach as _umul128, but just return the high half.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@223316 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Headers/Intrin.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/lib/Headers/Intrin.h b/lib/Headers/Intrin.h
index 8cd4a0dbf01..84bc4303a13 100644
--- a/lib/Headers/Intrin.h
+++ b/lib/Headers/Intrin.h
@@ -330,7 +330,6 @@ unsigned __int64 __shiftright128(unsigned __int64 _LowPart,
unsigned char _Shift);
static __inline__
void __stosq(unsigned __int64 *, unsigned __int64, size_t);
-unsigned __int64 __umulh(unsigned __int64, unsigned __int64);
unsigned char __vmx_on(unsigned __int64 *);
unsigned char __vmx_vmclear(unsigned __int64 *);
unsigned char __vmx_vmlaunch(void);
@@ -429,6 +428,12 @@ _umul128(unsigned __int64 _Multiplier, unsigned __int64 _Multiplicand,
*_HighProduct = _FullProduct >> 64;
return _FullProduct;
}
+static __inline__ unsigned __int64 __attribute__((__always_inline__, __nodebug__))
+__umulh(unsigned __int64 _Multiplier, unsigned __int64 _Multiplicand) {
+ unsigned __int128 _FullProduct =
+ (unsigned __int128)_Multiplier * (unsigned __int128)_Multiplicand;
+ return _FullProduct >> 64;
+}
void __cdecl _xrstor64(void const *, unsigned __int64);
void __cdecl _xsave64(void *, unsigned __int64);
void __cdecl _xsaveopt64(void *, unsigned __int64);
--
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