Introduce __builtin_expect() intrinsic support.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134761 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 269917b..8f29663 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -22,6 +22,7 @@
#include "clang/Basic/TargetBuiltins.h"
#include "llvm/Intrinsics.h"
#include "llvm/Target/TargetData.h"
+
using namespace clang;
using namespace CodeGen;
using namespace llvm;
@@ -311,11 +312,16 @@
return RValue::get(Result);
}
case Builtin::BI__builtin_expect: {
- // FIXME: pass expect through to LLVM
Value *ArgValue = EmitScalarExpr(E->getArg(0));
- if (E->getArg(1)->HasSideEffects(getContext()))
- (void)EmitScalarExpr(E->getArg(1));
- return RValue::get(ArgValue);
+ const llvm::Type *ArgType = ArgValue->getType();
+
+ Value *FnExpect = CGM.getIntrinsic(Intrinsic::expect, &ArgType, 1);
+ Value *ExpectedValue = EmitScalarExpr(E->getArg(1));
+
+ Value *Result = Builder.CreateCall2(FnExpect, ArgValue, ExpectedValue,
+ "expval");
+ return RValue::get(Result);
+
}
case Builtin::BI__builtin_bswap32:
case Builtin::BI__builtin_bswap64: {
diff --git a/test/CodeGen/builtin-expect.c b/test/CodeGen/builtin-expect.c
index 88479d9..664c6b6 100644
--- a/test/CodeGen/builtin-expect.c
+++ b/test/CodeGen/builtin-expect.c
@@ -19,3 +19,29 @@
// CHECK: call void @isigprocmask()
// CHECK: [[C:%.*]] = call i64 (...)* @bar()
+
+
+// CHECK: @test1
+int test1(int x) {
+// CHECK: @llvm.expect
+ if (__builtin_expect (x, 1))
+ return 0;
+ return x;
+}
+
+// CHECK: @test2
+int test2(int x) {
+// CHECK: @llvm.expect
+ switch(__builtin_expect(x, 5)) {
+ default:
+ return 0;
+ case 0:
+ case 1:
+ case 2:
+ return 1;
+ case 5:
+ return 5;
+ };
+
+ return 0;
+}