From a921a468542a804ccebb680935175798ac48868b Mon Sep 17 00:00:00 2001
From: Duncan Sands <baldrick@free.fr>
Date: Wed, 26 Oct 2011 14:11:18 +0000
Subject: [PATCH] Simplify SplitVecRes_UnaryOp by removing all the code that is
 trying to legalize the operand types when only the result type is required to
 be legalized - the type legalization machinery will get round to the operands
 later if they need legalizing. There can be a point to legalizing operands in
 parallel with the result: when this saves compile time or results in better
 code.  There was only one case in which this was true: when the operand is
 also split, so keep the logic for that bit. As a result of this change,
 additional operand legalization methods may need to be introduced to handle
 nodes where the result and operand types can differ, like SIGN_EXTEND, but
 the testsuite doesn't contain any tests where this is the case. In any case,
 it seems better to require such methods (and die with an assert if they
 doesn't exist) than to quietly produce wrong code if we forgot to special
 case the node in SplitVecRes_UnaryOp.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143026 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../SelectionDAG/LegalizeVectorTypes.cpp      | 48 ++-----------------
 1 file changed, 5 insertions(+), 43 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index 8916e082066..5f8931d1935 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -773,56 +773,18 @@ void DAGTypeLegalizer::SplitVecRes_UnaryOp(SDNode *N, SDValue &Lo,
   DebugLoc dl = N->getDebugLoc();
   GetSplitDestVTs(N->getValueType(0), LoVT, HiVT);
 
-  // Split the input.
+  // If the input also splits, handle it directly for a compile time speedup.
+  // Otherwise split it by hand.
   EVT InVT = N->getOperand(0).getValueType();
-  switch (getTypeAction(InVT)) {
-  default: llvm_unreachable("Unexpected type action!");
-  case TargetLowering::TypeLegal: {
+  if (getTypeAction(InVT) == TargetLowering::TypeSplitVector) {
+    GetSplitVector(N->getOperand(0), Lo, Hi);
+  } else {
     EVT InNVT = EVT::getVectorVT(*DAG.getContext(), InVT.getVectorElementType(),
                                  LoVT.getVectorNumElements());
     Lo = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, N->getOperand(0),
                      DAG.getIntPtrConstant(0));
     Hi = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, N->getOperand(0),
                      DAG.getIntPtrConstant(InNVT.getVectorNumElements()));
-    break;
-  }
-  case TargetLowering::TypePromoteInteger: {
-    SDValue InOp;
-    if (N->getOpcode() == ISD::SIGN_EXTEND ||
-        N->getOpcode() == ISD::SINT_TO_FP) {
-      InOp =   SExtPromotedInteger(N->getOperand(0));
-    } else if (
-        N->getOpcode() == ISD::ZERO_EXTEND ||
-        N->getOpcode() == ISD::UINT_TO_FP) {
-      InOp =   ZExtPromotedInteger(N->getOperand(0));
-    } else {
-      InOp = GetPromotedInteger(N->getOperand(0));
-    }
-    EVT InNVT = EVT::getVectorVT(*DAG.getContext(),
-                                 InOp.getValueType().getVectorElementType(),
-                                 LoVT.getVectorNumElements());
-    Lo = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
-                     DAG.getIntPtrConstant(0));
-    Hi = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
-                     DAG.getIntPtrConstant(InNVT.getVectorNumElements()));
-    break;
-  }
-  case TargetLowering::TypeSplitVector:
-    GetSplitVector(N->getOperand(0), Lo, Hi);
-    break;
-  case TargetLowering::TypeWidenVector: {
-    // If the result needs to be split and the input needs to be widened,
-    // the two types must have different lengths. Use the widened result
-    // and extract from it to do the split.
-    SDValue InOp = GetWidenedVector(N->getOperand(0));
-    EVT InNVT = EVT::getVectorVT(*DAG.getContext(), InVT.getVectorElementType(),
-                                 LoVT.getVectorNumElements());
-    Lo = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
-                     DAG.getIntPtrConstant(0));
-    Hi = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
-                     DAG.getIntPtrConstant(InNVT.getVectorNumElements()));
-    break;
-  }
   }
 
   if (N->getOpcode() == ISD::FP_ROUND) {