From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Fri, 25 Apr 2014 21:13:29 +0000 (+0000)
Subject: CodeGen: add __yield intrinsic for ARM
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a7b80b7a8fecae3d9d0d2691e83617400abf5919;p=clang

CodeGen: add __yield intrinsic for ARM

The __yield intrinsic generates a hint instruction to indicate that the thread
is not performing any useful operations at the moment.  This is for
compatibility with MSVC, although, the intrinsic is also part of the ACLE, and
is enabled globally as a result.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@207275 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/BuiltinsARM.def b/include/clang/Basic/BuiltinsARM.def
index aab9255a6d..99dbb9affa 100644
--- a/include/clang/Basic/BuiltinsARM.def
+++ b/include/clang/Basic/BuiltinsARM.def
@@ -65,4 +65,7 @@ BUILTIN(__builtin_arm_sevl, "v", "")
 BUILTIN(__builtin_arm_dmb, "vUi", "nc")
 BUILTIN(__builtin_arm_dsb, "vUi", "nc")
 
+// MSVC
+BUILTIN(__yield, "v", "")
+
 #undef BUILTIN
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index d267ecee73..56fa69aec5 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -4326,6 +4326,11 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
 
 Value *CodeGenFunction::EmitARMBuiltinExpr(unsigned BuiltinID,
                                            const CallExpr *E) {
+  if (BuiltinID == ARM::BI__yield) {
+    Function *F = CGM.getIntrinsic(Intrinsic::arm_hint);
+    return Builder.CreateCall(F, llvm::ConstantInt::get(Int32Ty, 1));
+  }
+
   if (BuiltinID == ARM::BI__clear_cache) {
     assert(E->getNumArgs() == 2 && "__clear_cache takes 2 arguments");
     const FunctionDecl *FD = E->getDirectCallee();
diff --git a/test/CodeGen/builtins-arm-microsoft.c b/test/CodeGen/builtins-arm-microsoft.c
new file mode 100644
index 0000000000..682ec916a8
--- /dev/null
+++ b/test/CodeGen/builtins-arm-microsoft.c
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple thumbv7-windows -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple armv7-eabi -emit-llvm -o - %s | FileCheck %s
+// REQUIRES: arm-registered-target
+
+void test_yield_intrinsic() {
+  __yield();
+}
+
+// CHECK: call void @llvm.arm.hint(i32 1)
+