Add code to check at SelectionDAGISel::LowerArguments time to see if return values can be lowered to registers. Coming soon, code to perform sret-demotion if return values cannot be lowered to registers

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86324 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 17 insertions, 0 deletions

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 86ec9f2..3b11ef4 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1087,6 +1087,17 @@ unsigned X86TargetLowering::getFunctionAlignment(const Function *F) const {
 
 #include "X86GenCallingConv.inc"
 
+bool 
+X86TargetLowering::CanLowerReturn(CallingConv::ID CallConv, bool isVarArg,
+                        const SmallVectorImpl<EVT> &OutTys,
+                        const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
+                        SelectionDAG &DAG) {
+  SmallVector<CCValAssign, 16> RVLocs;
+  CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
+                 RVLocs, *DAG.getContext());
+  return CCInfo.CheckReturn(OutTys, ArgsFlags, RetCC_X86);
+}
+
 SDValue
 X86TargetLowering::LowerReturn(SDValue Chain,
                                CallingConv::ID CallConv, bool isVarArg,
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index 7b59b81..0755284 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -699,6 +699,12 @@ namespace llvm {
                   const SmallVectorImpl<ISD::OutputArg> &Outs,
                   DebugLoc dl, SelectionDAG &DAG);
 
+    virtual bool
+      CanLowerReturn(CallingConv::ID CallConv, bool isVarArg,
+                     const SmallVectorImpl<EVT> &OutTys,
+                     const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
+                     SelectionDAG &DAG);
+
     void ReplaceATOMIC_BINARY_64(SDNode *N, SmallVectorImpl<SDValue> &Results,
                                  SelectionDAG &DAG, unsigned NewOp);