[X86] Better support for the MCU psABI (LLVM part)

[oota-llvm.git] / lib / Target / X86 / X86FastISel.cpp

diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index 914fd04ad6b7f7cfaa18ae284f17a2988487c6ef..de94a138d865e51962a443d4ace8cafb7476abc9 100644 (file)
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -1098,12 +1098,11 @@ bool X86FastISel::X86SelectRet(const Instruction *I) {
     RetRegs.push_back(VA.getLocReg());
   }
 
-  // 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. We also do the same with %eax for Win32.
-  if (F.hasStructRetAttr() &&
-      (Subtarget->is64Bit() || Subtarget->isTargetKnownWindowsMSVC())) {
+  // All x86 ABIs require that for returning structs by value we copy\r
+  // the sret argument into %rax/%eax (depending on ABI) for the return.\r
+  // We saved the argument into a virtual register in the entry block,\r
+  // so now we copy the value out and into %rax/%eax.
+  if (F.hasStructRetAttr()) {
     unsigned Reg = X86MFInfo->getSRetReturnReg();
     assert(Reg &&
            "SRetReturnReg should have been set in LowerFormalArguments()!");
@@ -2820,7 +2819,7 @@ static unsigned computeBytesPoppedByCallee(const X86Subtarget *Subtarget,
 
   if (CS)
     if (CS->arg_empty() || !CS->paramHasAttr(1, Attribute::StructRet) ||
-        CS->paramHasAttr(1, Attribute::InReg))
+        CS->paramHasAttr(1, Attribute::InReg) || Subtarget->isTargetMCU())
       return 0;
 
   return 4;