Make Win32 put the SRet address into EAX, fixes PR15556

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178291 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 16 insertions, 9 deletions

diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index 85155f55e0..c5da0b9b16 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -816,14 +816,16 @@ bool X86FastISel::X86SelectRet(const Instruction *I) {
   // The x86-64 ABI for returning structs by value requires that we copy
   // the sret argument into %rax for the return. We saved the argument into
   // a virtual register in the entry block, so now we copy the value out
-  // and into %rax.
-  if (Subtarget->is64Bit() && F.hasStructRetAttr()) {
+  // and into %rax. We also do the same with %eax for Win32.
+  if (F.hasStructRetAttr() &&
+      (Subtarget->is64Bit() || Subtarget->isTargetWindows())) {
     unsigned Reg = X86MFInfo->getSRetReturnReg();
     assert(Reg &&
            "SRetReturnReg should have been set in LowerFormalArguments()!");
+    unsigned RetReg = Subtarget->is64Bit() ? X86::RAX : X86::EAX;
     BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
-            X86::RAX).addReg(Reg);
-    RetRegs.push_back(X86::RAX);
+            RetReg).addReg(Reg);
+    RetRegs.push_back(RetReg);
   }
 
   // Now emit the RET.
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 0eaab0f818..bff5426f90 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1666,10 +1666,11 @@ X86TargetLowering::LowerReturn(SDValue Chain,
 
   // The x86-64 ABIs require that for returning structs by value we copy
   // the sret argument into %rax/%eax (depending on ABI) for the return.
+  // Win32 requires us to put the sret argument to %eax as well.
   // We saved the argument into a virtual register in the entry block,
   // so now we copy the value out and into %rax/%eax.
-  if (Subtarget->is64Bit() &&
-      DAG.getMachineFunction().getFunction()->hasStructRetAttr()) {
+  if (DAG.getMachineFunction().getFunction()->hasStructRetAttr() &&
+      (Subtarget->is64Bit() || Subtarget->isTargetWindows())) {
     MachineFunction &MF = DAG.getMachineFunction();
     X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
     unsigned Reg = FuncInfo->getSRetReturnReg();
@@ -1677,12 +1678,14 @@ X86TargetLowering::LowerReturn(SDValue Chain,
            "SRetReturnReg should have been set in LowerFormalArguments().");
     SDValue Val = DAG.getCopyFromReg(Chain, dl, Reg, getPointerTy());
 
-    unsigned RetValReg = Subtarget->isTarget64BitILP32() ? X86::EAX : X86::RAX;
+    unsigned RetValReg
+        = (Subtarget->is64Bit() && !Subtarget->isTarget64BitILP32()) ?
+          X86::RAX : X86::EAX;
     Chain = DAG.getCopyToReg(Chain, dl, RetValReg, Val, Flag);
     Flag = Chain.getValue(1);
 
     // RAX/EAX now acts like a return value.
-    RetOps.push_back(DAG.getRegister(RetValReg, MVT::i64));
+    RetOps.push_back(DAG.getRegister(RetValReg, getPointerTy()));
   }
 
   RetOps[0] = Chain;  // Update chain.
@@ -2036,9 +2039,11 @@ X86TargetLowering::LowerFormalArguments(SDValue Chain,
 
   // The x86-64 ABIs require that for returning structs by value we copy
   // the sret argument into %rax/%eax (depending on ABI) for the return.
+  // Win32 requires us to put the sret argument to %eax as well.
   // Save the argument into a virtual register so that we can access it
   // from the return points.
-  if (Is64Bit && MF.getFunction()->hasStructRetAttr()) {
+  if (MF.getFunction()->hasStructRetAttr() &&
+      (Subtarget->is64Bit() || Subtarget->isTargetWindows())) {
     X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
     unsigned Reg = FuncInfo->getSRetReturnReg();
     if (!Reg) {