From 27608d83939ba31f124bebd2d1d6bed8bb4eda0b Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault@amd.com>
Date: Wed, 17 Sep 2014 15:35:43 +0000
Subject: [PATCH] R600/SI: Remove promotion of instructions to e64 forms.

Instructions are now generally selected to the e64 forms originally,
and shrunk down later. Rename foldOperands to legalizeOperands,
since that's really most of what it tries to do.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217959 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/R600/SIISelLowering.cpp | 62 +++---------------------------
 lib/Target/R600/SIISelLowering.h   |  2 +-
 2 files changed, 6 insertions(+), 58 deletions(-)

diff --git a/lib/Target/R600/SIISelLowering.cpp b/lib/Target/R600/SIISelLowering.cpp
index 9eef742e83d..7b969d7ead3 100644
--- a/lib/Target/R600/SIISelLowering.cpp
+++ b/lib/Target/R600/SIISelLowering.cpp
@@ -1666,10 +1666,10 @@ static bool isNodeChanged(const SDNode *Node, const std::vector<SDValue> &Ops) {
   return false;
 }
 
-/// \brief Try to fold the Nodes operands into the Node
-SDNode *SITargetLowering::foldOperands(MachineSDNode *Node,
-                                       SelectionDAG &DAG) const {
-
+/// \brief Try to commute instructions and insert copies in order to satisfy the
+/// operand constraints.
+SDNode *SITargetLowering::legalizeOperands(MachineSDNode *Node,
+                                           SelectionDAG &DAG) const {
   // Original encoding (either e32 or e64)
   int Opcode = Node->getMachineOpcode();
   const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
@@ -1686,13 +1686,6 @@ SDNode *SITargetLowering::foldOperands(MachineSDNode *Node,
   assert(!DescRev || DescRev->getNumDefs() == NumDefs);
   assert(!DescRev || DescRev->getNumOperands() == NumOps);
 
-  // e64 version if available, -1 otherwise
-  int OpcodeE64 = AMDGPU::getVOPe64(Opcode);
-  const MCInstrDesc *DescE64 = OpcodeE64 == -1 ? nullptr : &TII->get(OpcodeE64);
-  int InputModifiers[3] = {0};
-
-  assert(!DescE64 || DescE64->getNumDefs() == NumDefs);
-
   int32_t Immediate = Desc->getSize() == 4 ? 0 : -1;
   bool HaveVSrc = false, HaveSSrc = false;
 
@@ -1724,7 +1717,6 @@ SDNode *SITargetLowering::foldOperands(MachineSDNode *Node,
 
   // Second go over the operands and try to fold them
   std::vector<SDValue> Ops;
-  bool Promote2e64 = false;
   for (unsigned i = 0, e = Node->getNumOperands(), Op = NumDefs;
        i != e && Op < NumOps; ++i, ++Op) {
 
@@ -1773,50 +1765,6 @@ SDNode *SITargetLowering::foldOperands(MachineSDNode *Node,
         continue;
       }
     }
-
-    if (Immediate)
-      continue;
-
-    if (DescE64) {
-      // Test if it makes sense to switch to e64 encoding
-      unsigned OtherRegClass = DescE64->OpInfo[Op].RegClass;
-      if (!isVSrc(OtherRegClass) && !isSSrc(OtherRegClass))
-        continue;
-
-      int32_t TmpImm = -1;
-      if (foldImm(Ops[i], TmpImm, ScalarSlotUsed) ||
-          (!fitsRegClass(DAG, Ops[i], RegClass) &&
-           fitsRegClass(DAG, Ops[1], OtherRegClass))) {
-
-        // Switch to e64 encoding
-        Immediate = -1;
-        Promote2e64 = true;
-        Desc = DescE64;
-        DescE64 = nullptr;
-      }
-    }
-
-    if (!DescE64 && !Promote2e64)
-      continue;
-    if (!Operand.isMachineOpcode())
-      continue;
-  }
-
-  if (Promote2e64) {
-    std::vector<SDValue> OldOps(Ops);
-    Ops.clear();
-    bool HasModifiers = TII->hasModifiers(Desc->Opcode);
-    for (unsigned i = 0; i < OldOps.size(); ++i) {
-      // src_modifier
-      if (HasModifiers)
-        Ops.push_back(DAG.getTargetConstant(InputModifiers[i], MVT::i32));
-      Ops.push_back(OldOps[i]);
-    }
-    // Add the modifier flags while promoting
-    if (HasModifiers) {
-      for (unsigned i = 0; i < 2; ++i)
-        Ops.push_back(DAG.getTargetConstant(0, MVT::i32));
-    }
   }
 
   // Add optional chain and glue
@@ -1935,7 +1883,7 @@ SDNode *SITargetLowering::PostISelFolding(MachineSDNode *Node,
   if (TII->isMIMG(Node->getMachineOpcode()))
     adjustWritemask(Node, DAG);
 
-  return foldOperands(Node, DAG);
+  return legalizeOperands(Node, DAG);
 }
 
 /// \brief Assign the register class depending on the number of
diff --git a/lib/Target/R600/SIISelLowering.h b/lib/Target/R600/SIISelLowering.h
index b952bc0345a..f953b482fdd 100644
--- a/lib/Target/R600/SIISelLowering.h
+++ b/lib/Target/R600/SIISelLowering.h
@@ -50,7 +50,7 @@ class SITargetLowering : public AMDGPUTargetLowering {
   void ensureSRegLimit(SelectionDAG &DAG, SDValue &Operand,
                        unsigned RegClass, bool &ScalarSlotUsed) const;
 
-  SDNode *foldOperands(MachineSDNode *N, SelectionDAG &DAG) const;
+  SDNode *legalizeOperands(MachineSDNode *N, SelectionDAG &DAG) const;
   void adjustWritemask(MachineSDNode *&N, SelectionDAG &DAG) const;
   MachineSDNode *AdjustRegClass(MachineSDNode *N, SelectionDAG &DAG) const;