Teach legalize to promote copy(from|to)reg, instead of making the isel pass

do it.  This results in better code on X86 for floats (because if strict
precision is not required, we can elide some more expensive double -> float
conversions like the old isel did), and allows other targets to emit
CopyFromRegs that are not legal for arguments.

llvm-svn: 19668

1 files changed, 1 insertions, 21 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 09b5f3c010b..a17caa1469a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -292,19 +292,7 @@ public:
       FuncInfo.ValueMap.find(V);
     assert(VMI != FuncInfo.ValueMap.end() && "Value not in map!");
 
-    MVT::ValueType RegVT = VT;
-    if (TLI.getTypeAction(VT) == 1)          // Must promote this value?
-      RegVT = TLI.getTypeToTransformTo(VT);
-
-    N = DAG.getCopyFromReg(VMI->second, RegVT, DAG.getEntryNode());
-
-    if (RegVT != VT)
-      if (MVT::isFloatingPoint(VT))
-        N = DAG.getNode(ISD::FP_ROUND, VT, N);
-      else
-        N = DAG.getNode(ISD::TRUNCATE, VT, N);
-
-    return N;
+    return N = DAG.getCopyFromReg(VMI->second, VT, DAG.getEntryNode());
   }
 
   const SDOperand &setValue(const Value *V, SDOperand NewN) {
@@ -843,14 +831,6 @@ CopyValueToVirtualRegister(SelectionDAGLowering &SDL, Value *V, unsigned Reg) {
   assert((Op.getOpcode() != ISD::CopyFromReg ||
           cast<RegSDNode>(Op)->getReg() != Reg) &&
          "Copy from a reg to the same reg!");
-  MVT::ValueType VT = Op.getValueType();
-  if (TLI.getTypeAction(VT) == 1) {       // Must promote this value?
-    if (MVT::isFloatingPoint(VT))
-      Op = DAG.getNode(ISD::FP_EXTEND, TLI.getTypeToTransformTo(VT), Op);
-    else
-      Op = DAG.getNode(ISD::ZERO_EXTEND, TLI.getTypeToTransformTo(VT), Op);
-  }
-
   return DAG.getCopyToReg(SDL.getRoot(), Op, Reg);
 }