1 files changed, 23 insertions, 6 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 1b04cf46fc..bfe93877e4 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2584,9 +2584,21 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
       X86Info->setTCReturnAddrDelta(FPDiff);
   }
 
+  unsigned NumBytesToPush = NumBytes;
+  unsigned NumBytesToPop = NumBytes;
+
+  // If we have an inalloca argument, all stack space has already been allocated
+  // for us and be right at the top of the stack.  We don't support multiple
+  // arguments passed in memory when using inalloca.
+  if (!Outs.empty() && Outs.back().Flags.isInAlloca()) {
+    NumBytesToPush = 0;
+    assert(ArgLocs.back().getLocMemOffset() == 0 &&
+           "an inalloca argument must be the only memory argument");
+  }
+
   if (!IsSibcall)
-    Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(NumBytes, true),
-                                 dl);
+    Chain = DAG.getCALLSEQ_START(
+        Chain, DAG.getIntPtrConstant(NumBytesToPush, true), dl);
 
   SDValue RetAddrFrIdx;
   // Load return address for tail calls.
@@ -2603,10 +2615,14 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   const X86RegisterInfo *RegInfo =
     static_cast<const X86RegisterInfo*>(getTargetMachine().getRegisterInfo());
   for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
+    // Skip inalloca arguments, they have already been written.
+    ISD::ArgFlagsTy Flags = Outs[i].Flags;
+    if (Flags.isInAlloca())
+      continue;
+
     CCValAssign &VA = ArgLocs[i];
     EVT RegVT = VA.getLocVT();
     SDValue Arg = OutVals[i];
-    ISD::ArgFlagsTy Flags = Outs[i].Flags;
     bool isByVal = Flags.isByVal();
 
     // Promote the value if needed.
@@ -2873,8 +2889,9 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   SmallVector<SDValue, 8> Ops;
 
   if (!IsSibcall && isTailCall) {
-    Chain = DAG.getCALLSEQ_END(Chain, DAG.getIntPtrConstant(NumBytes, true),
-                           DAG.getIntPtrConstant(0, true), InFlag, dl);
+    Chain = DAG.getCALLSEQ_END(Chain,
+                               DAG.getIntPtrConstant(NumBytesToPop, true),
+                               DAG.getIntPtrConstant(0, true), InFlag, dl);
     InFlag = Chain.getValue(1);
   }
 
@@ -2931,7 +2948,7 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   // Returns a flag for retval copy to use.
   if (!IsSibcall) {
     Chain = DAG.getCALLSEQ_END(Chain,
-                               DAG.getIntPtrConstant(NumBytes, true),
+                               DAG.getIntPtrConstant(NumBytesToPop, true),
                                DAG.getIntPtrConstant(NumBytesForCalleeToPop,
                                                      true),
                                InFlag, dl);