[AMDGPU] Divergence driven ISel. Assign register class for cross block values according to the divergence.

    Details: To make instruction selection really divergence driven it is necessary to assign
             the correct register classes to the cross block values beforehand. For the divergent targets
             same value type requires different register classes dependent on the value divergence.

    Reviewers: rampitec, nhaehnle

    Differential Revision: https://reviews.llvm.org/D59990

    This commit was reverted because of the build failure.
    The reason was mlformed patch.
    Build failure fixed.

llvm-svn: 361741

1 files changed, 19 insertions, 14 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index 059e5f7c8dd..4b78d1bb6b1 100644
--- a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -105,7 +105,7 @@ EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned,
 
   // Stick to the preferred register classes for legal types.
   if (TLI->isTypeLegal(VT))
-    UseRC = TLI->getRegClassFor(VT);
+    UseRC = TLI->getRegClassFor(VT, Node->isDivergent());
 
   if (!IsClone && !IsCloned)
     for (SDNode *User : Node->uses()) {
@@ -164,7 +164,7 @@ EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned,
            "Incompatible phys register def and uses!");
     DstRC = UseRC;
   } else {
-    DstRC = TLI->getRegClassFor(VT);
+    DstRC = TLI->getRegClassFor(VT, Node->isDivergent());
   }
 
   // If all uses are reading from the src physical register and copying the
@@ -225,8 +225,9 @@ void InstrEmitter::CreateVirtualRegisters(SDNode *Node,
     // type correctly. For example, a 64-bit float (X86::FR64) can't live in
     // the 32-bit float super-class (X86::FR32).
     if (i < NumResults && TLI->isTypeLegal(Node->getSimpleValueType(i))) {
-      const TargetRegisterClass *VTRC =
-        TLI->getRegClassFor(Node->getSimpleValueType(i));
+      const TargetRegisterClass *VTRC = TLI->getRegClassFor(
+          Node->getSimpleValueType(i),
+          (Node->isDivergent() || (RC && TRI->isDivergentRegClass(RC))));
       if (RC)
         VTRC = TRI->getCommonSubClass(RC, VTRC);
       if (VTRC)
@@ -289,8 +290,8 @@ unsigned InstrEmitter::getVR(SDValue Op,
     // IMPLICIT_DEF can produce any type of result so its MCInstrDesc
     // does not include operand register class info.
     if (!VReg) {
-      const TargetRegisterClass *RC =
-        TLI->getRegClassFor(Op.getSimpleValueType());
+      const TargetRegisterClass *RC = TLI->getRegClassFor(
+          Op.getSimpleValueType(), Op.getNode()->isDivergent());
       VReg = MRI->createVirtualRegister(RC);
     }
     BuildMI(*MBB, InsertPos, Op.getDebugLoc(),
@@ -395,11 +396,15 @@ void InstrEmitter::AddOperand(MachineInstrBuilder &MIB,
   } else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) {
     unsigned VReg = R->getReg();
     MVT OpVT = Op.getSimpleValueType();
-    const TargetRegisterClass *OpRC =
-        TLI->isTypeLegal(OpVT) ? TLI->getRegClassFor(OpVT) : nullptr;
     const TargetRegisterClass *IIRC =
         II ? TRI->getAllocatableClass(TII->getRegClass(*II, IIOpNum, TRI, *MF))
            : nullptr;
+    const TargetRegisterClass *OpRC =
+        TLI->isTypeLegal(OpVT)
+            ? TLI->getRegClassFor(OpVT,
+                                  Op.getNode()->isDivergent() ||
+                                      (IIRC && TRI->isDivergentRegClass(IIRC)))
+            : nullptr;
 
     if (OpRC && IIRC && OpRC != IIRC &&
         TargetRegisterInfo::isVirtualRegister(VReg)) {
@@ -464,7 +469,7 @@ void InstrEmitter::AddOperand(MachineInstrBuilder &MIB,
 }
 
 unsigned InstrEmitter::ConstrainForSubReg(unsigned VReg, unsigned SubIdx,
-                                          MVT VT, const DebugLoc &DL) {
+                                          MVT VT, bool isDivergent, const DebugLoc &DL) {
   const TargetRegisterClass *VRC = MRI->getRegClass(VReg);
   const TargetRegisterClass *RC = TRI->getSubClassWithSubReg(VRC, SubIdx);
 
@@ -479,7 +484,7 @@ unsigned InstrEmitter::ConstrainForSubReg(unsigned VReg, unsigned SubIdx,
 
   // VReg couldn't be reasonably constrained.  Emit a COPY to a new virtual
   // register instead.
-  RC = TRI->getSubClassWithSubReg(TLI->getRegClassFor(VT), SubIdx);
+  RC = TRI->getSubClassWithSubReg(TLI->getRegClassFor(VT, isDivergent), SubIdx);
   assert(RC && "No legal register class for VT supports that SubIdx");
   unsigned NewReg = MRI->createVirtualRegister(RC);
   BuildMI(*MBB, InsertPos, DL, TII->get(TargetOpcode::COPY), NewReg)
@@ -514,7 +519,7 @@ void InstrEmitter::EmitSubregNode(SDNode *Node,
     // classes.
     unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
     const TargetRegisterClass *TRC =
-      TLI->getRegClassFor(Node->getSimpleValueType(0));
+      TLI->getRegClassFor(Node->getSimpleValueType(0), Node->isDivergent());
 
     unsigned Reg;
     MachineInstr *DefMI;
@@ -548,8 +553,7 @@ void InstrEmitter::EmitSubregNode(SDNode *Node,
       if (TargetRegisterInfo::isVirtualRegister(Reg))
         Reg = ConstrainForSubReg(Reg, SubIdx,
                                  Node->getOperand(0).getSimpleValueType(),
-                                 Node->getDebugLoc());
-
+                                 Node->isDivergent(), Node->getDebugLoc());
       // Create the destreg if it is missing.
       if (VRBase == 0)
         VRBase = MRI->createVirtualRegister(TRC);
@@ -584,7 +588,8 @@ void InstrEmitter::EmitSubregNode(SDNode *Node,
     //
     // There is no constraint on the %src register class.
     //
-    const TargetRegisterClass *SRC = TLI->getRegClassFor(Node->getSimpleValueType(0));
+    const TargetRegisterClass *SRC =
+        TLI->getRegClassFor(Node->getSimpleValueType(0), Node->isDivergent());
     SRC = TRI->getSubClassWithSubReg(SRC, SubIdx);
     assert(SRC && "No register class supports VT and SubIdx for INSERT_SUBREG");