Major calling convention code refactoring.

Instead of awkwardly encoding calling-convention information with ISD::CALL,
ISD::FORMAL_ARGUMENTS, ISD::RET, and ISD::ARG_FLAGS nodes, TargetLowering
provides three virtual functions for targets to override:
LowerFormalArguments, LowerCall, and LowerRet, which replace the custom
lowering done on the special nodes. They provide the same information, but
in a more immediately usable format.

This also reworks much of the target-independent tail call logic. The
decision of whether or not to perform a tail call is now cleanly split
between target-independent portions, and the target dependent portion
in IsEligibleForTailCallOptimization.

This also synchronizes all in-tree targets, to help enable future
refactoring and feature work.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78142 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 42 deletions

diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 21b8cce77f..3c5305d226 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -2584,45 +2584,3 @@ SDValue TargetLowering::BuildUDIV(SDNode *N, SelectionDAG &DAG,
                        DAG.getConstant(magics.s-1, getShiftAmountTy()));
   }
 }
-
-/// IgnoreHarmlessInstructions - Ignore instructions between a CALL and RET
-/// node that don't prevent tail call optimization.
-static SDValue IgnoreHarmlessInstructions(SDValue node) {
-  // Found call return.
-  if (node.getOpcode() == ISD::CALL) return node;
-  // Ignore MERGE_VALUES. Will have at least one operand.
-  if (node.getOpcode() == ISD::MERGE_VALUES)
-    return IgnoreHarmlessInstructions(node.getOperand(0));
-  // Ignore ANY_EXTEND node.
-  if (node.getOpcode() == ISD::ANY_EXTEND)
-    return IgnoreHarmlessInstructions(node.getOperand(0));
-  if (node.getOpcode() == ISD::TRUNCATE)
-    return IgnoreHarmlessInstructions(node.getOperand(0));
-  // Any other node type.
-  return node;
-} 
-
-bool TargetLowering::CheckTailCallReturnConstraints(CallSDNode *TheCall,
-                                                    SDValue Ret) {
-  unsigned NumOps = Ret.getNumOperands();
-  // ISD::CALL results:(value0, ..., valuen, chain)
-  // ISD::RET  operands:(chain, value0, flag0, ..., valuen, flagn)
-  // Value return:
-  // Check that operand of the RET node sources from the CALL node. The RET node
-  // has at least two operands. Operand 0 holds the chain. Operand 1 holds the
-  // value.
-  // Also we need to check that there is no code in between the call and the
-  // return. Hence we also check that the incomming chain to the return sources
-  // from the outgoing chain of the call.
-  if (NumOps > 1 &&
-      IgnoreHarmlessInstructions(Ret.getOperand(1)) == SDValue(TheCall,0) &&
-      Ret.getOperand(0) == SDValue(TheCall, TheCall->getNumValues()-1))
-    return true;
-  // void return: The RET node  has the chain result value of the CALL node as
-  // input.
-  if (NumOps == 1 &&
-      Ret.getOperand(0) == SDValue(TheCall, TheCall->getNumValues()-1))
-    return true;
-
-  return false;
-}