Implement LowerReturn_64 for SPARC v9.

Integer return values are sign or zero extended by the callee, and
structs up to 32 bytes in size can be returned in registers.

The CC_Sparc64 CallingConv definition is shared between
LowerFormalArguments_64 and LowerReturn_64. Function arguments and
return values are passed in the same registers.

The inreg flag is also used for return values. This is required to handle
C functions returning structs containing floats and ints:

  struct ifp {
    int i;
    float f;
  };

  struct ifp f(void);

LLVM IR:

  define inreg { i32, float } @f() {
     ...
     ret { i32, float } %retval
  }

The ABI requires that %retval.i is returned in the high bits of %i0
while %retval.f goes in %f1.

Without the inreg return value attribute, %retval.i would go in %i0 and
%retval.f would go in %f3 which is a more efficient way of returning
%multiple values, but it is not ABI compliant for returning C structs.

llvm-svn: 178966

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.h b/llvm/lib/Target/Sparc/SparcISelLowering.h
index aa2ef711a08..189a3882d3c 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.h
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.h
@@ -102,6 +102,16 @@ namespace llvm {
                   const SmallVectorImpl<ISD::OutputArg> &Outs,
                   const SmallVectorImpl<SDValue> &OutVals,
                   DebugLoc dl, SelectionDAG &DAG) const;
+    SDValue LowerReturn_32(SDValue Chain,
+                           CallingConv::ID CallConv, bool IsVarArg,
+                           const SmallVectorImpl<ISD::OutputArg> &Outs,
+                           const SmallVectorImpl<SDValue> &OutVals,
+                           DebugLoc DL, SelectionDAG &DAG) const;
+    SDValue LowerReturn_64(SDValue Chain,
+                           CallingConv::ID CallConv, bool IsVarArg,
+                           const SmallVectorImpl<ISD::OutputArg> &Outs,
+                           const SmallVectorImpl<SDValue> &OutVals,
+                           DebugLoc DL, SelectionDAG &DAG) const;
 
     SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerConstantPool(SDValue Op, SelectionDAG &DAG) const;