ARM: Support for __builtin_arm_rbit() intrinsic.

Reverse the bits in a word. Maps to the RBIT instruction.

rdar://9283021

llvm-svn: 211059

3 files changed, 15 insertions, 0 deletions

diff --git a/clang/include/clang/Basic/BuiltinsARM.def b/clang/include/clang/Basic/BuiltinsARM.def
index 9f650cc4154..00cd2c1de41 100644
--- a/clang/include/clang/Basic/BuiltinsARM.def
+++ b/clang/include/clang/Basic/BuiltinsARM.def
@@ -24,6 +24,9 @@ BUILTIN(__builtin_arm_qsub, "iii", "nc")
 BUILTIN(__builtin_arm_ssat, "iiUi", "nc")
 BUILTIN(__builtin_arm_usat, "UiUiUi", "nc")
 
+// Bit manipulation
+BUILTIN(__builtin_arm_rbit, "UiUi", "nc")
+
 // Store and load exclusive
 BUILTIN(__builtin_arm_ldrexd, "LLUiv*", "")
 BUILTIN(__builtin_arm_strexd, "iLLUiv*", "")
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 47245cf2d83..f4e11509a9d 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3054,6 +3054,12 @@ Value *CodeGenFunction::EmitARMBuiltinExpr(unsigned BuiltinID,
     return Builder.CreateCall(F, llvm::ConstantInt::get(Int32Ty, HintID));
   }
 
+  if (BuiltinID == ARM::BI__builtin_arm_rbit) {
+    return Builder.CreateCall(CGM.getIntrinsic(Intrinsic::arm_rbit),
+                                               EmitScalarExpr(E->getArg(0)),
+                              "rbit");
+  }
+
   if (BuiltinID == ARM::BI__clear_cache) {
     assert(E->getNumArgs() == 2 && "__clear_cache takes 2 arguments");
     const FunctionDecl *FD = E->getDirectCallee();
diff --git a/clang/test/CodeGen/builtins-arm.c b/clang/test/CodeGen/builtins-arm.c
index c5e487aafd6..13ffc607849 100644
--- a/clang/test/CodeGen/builtins-arm.c
+++ b/clang/test/CodeGen/builtins-arm.c
@@ -52,3 +52,9 @@ void test_barrier() {
   __builtin_arm_dmb(1); //CHECK: call {{.*}} @llvm.arm.dmb(i32 1)
   __builtin_arm_dsb(2); //CHECK: call {{.*}} @llvm.arm.dsb(i32 2)
 }
+
+// CHECK: call {{.*}} @llvm.arm.rbit(i32 %a)
+
+unsigned rbit(unsigned a) {
+  return __builtin_arm_rbit(a);
+}