From: David Majnemer <david.majnemer@gmail.com>
Date: Fri, 1 Jan 2016 06:50:08 +0000 (+0000)
Subject: Reimplement __readeflags and __writeeflags on top of intrinsics
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=93d12f762adfed45408403abf5f2cb23826516c1;p=clang

Reimplement __readeflags and __writeeflags on top of intrinsics

Lean on LLVM to provide this functionality now that it provides the
necessary intrinsics.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@256686 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/BuiltinsX86.def b/include/clang/Basic/BuiltinsX86.def
index 64fa4da9bb..f738cc12a4 100644
--- a/include/clang/Basic/BuiltinsX86.def
+++ b/include/clang/Basic/BuiltinsX86.def
@@ -41,6 +41,13 @@ TARGET_BUILTIN(__builtin_ia32_undef128, "V2d", "nc", "")
 TARGET_BUILTIN(__builtin_ia32_undef256, "V4d", "nc", "")
 TARGET_BUILTIN(__builtin_ia32_undef512, "V8d", "nc", "")
 
+// FLAGS
+//
+TARGET_BUILTIN(__builtin_ia32_readeflags_u32, "Ui", "n", "")
+TARGET_BUILTIN(__builtin_ia32_readeflags_u64, "ULLi", "n", "")
+TARGET_BUILTIN(__builtin_ia32_writeeflags_u32, "vUi", "n", "")
+TARGET_BUILTIN(__builtin_ia32_writeeflags_u64, "vULLi", "n", "")
+
 // 3DNow!
 //
 TARGET_BUILTIN(__builtin_ia32_femms, "v", "", "3dnow")
diff --git a/lib/Headers/ia32intrin.h b/lib/Headers/ia32intrin.h
index 5adf3f1f5d..b2f82bb59e 100644
--- a/lib/Headers/ia32intrin.h
+++ b/lib/Headers/ia32intrin.h
@@ -32,50 +32,26 @@
 static __inline__ unsigned long long __attribute__((__always_inline__, __nodebug__))
 __readeflags(void)
 {
-  unsigned long long __res = 0;
-  __asm__ __volatile__ ("pushf\n\t"
-                        "popq %0\n"
-                        :"=r"(__res)
-                        :
-                        :
-                       );
-  return __res;
+  return __builtin_ia32_readeflags_u64();
 }
 
 static __inline__ void __attribute__((__always_inline__, __nodebug__))
 __writeeflags(unsigned long long __f)
 {
-  __asm__ __volatile__ ("pushq %0\n\t"
-                        "popf\n"
-                        :
-                        :"r"(__f)
-                        :"flags"
-                       );
+  __builtin_ia32_writeeflags_u64(__f);
 }
 
 #else /* !__x86_64__ */
 static __inline__ unsigned int __attribute__((__always_inline__, __nodebug__))
 __readeflags(void)
 {
-  unsigned int __res = 0;
-  __asm__ __volatile__ ("pushf\n\t"
-                        "popl %0\n"
-                        :"=r"(__res)
-                        :
-                        :
-                       );
-  return __res;
+  return __builtin_ia32_readeflags_u32();
 }
 
 static __inline__ void __attribute__((__always_inline__, __nodebug__))
 __writeeflags(unsigned int __f)
 {
-  __asm__ __volatile__ ("pushl %0\n\t"
-                        "popf\n"
-                        :
-                        :"r"(__f)
-                        :"flags"
-                       );
+  __builtin_ia32_writeeflags_u32(__f);
 }
 #endif /* !__x86_64__ */