[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

6 files changed, 37 insertions, 24 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 117654bc7a3..d53ee3134d5 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -13919,9 +13919,11 @@ struct LoadedSlice {
     assert(DAG && "Missing context");
     const TargetLowering &TLI = DAG->getTargetLoweringInfo();
     EVT ResVT = Use->getValueType(0);
-    const TargetRegisterClass *ResRC = TLI.getRegClassFor(ResVT.getSimpleVT());
+    const TargetRegisterClass *ResRC =
+        TLI.getRegClassFor(ResVT.getSimpleVT(), Use->isDivergent());
     const TargetRegisterClass *ArgRC =
-        TLI.getRegClassFor(Use->getOperand(0).getValueType().getSimpleVT());
+        TLI.getRegClassFor(Use->getOperand(0).getValueType().getSimpleVT(),
+                           Use->getOperand(0)->isDivergent());
     if (ArgRC == ResRC || !TLI.isOperationLegal(ISD::LOAD, ResVT))
       return false;
 
diff --git a/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
index d8ef10f58aa..8b405562904 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
@@ -85,6 +85,7 @@ void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
   RegInfo = &MF->getRegInfo();
   const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
   unsigned StackAlign = TFI->getStackAlignment();
+  DA = DAG->getDivergenceAnalysis();
 
   // Check whether the function can return without sret-demotion.
   SmallVector<ISD::OutputArg, 4> Outs;
@@ -345,9 +346,9 @@ void FunctionLoweringInfo::clear() {
 }
 
 /// CreateReg - Allocate a single virtual register for the given type.
-unsigned FunctionLoweringInfo::CreateReg(MVT VT) {
+unsigned FunctionLoweringInfo::CreateReg(MVT VT, bool isDivergent) {
   return RegInfo->createVirtualRegister(
-      MF->getSubtarget().getTargetLowering()->getRegClassFor(VT));
+      MF->getSubtarget().getTargetLowering()->getRegClassFor(VT, isDivergent));
 }
 
 /// CreateRegs - Allocate the appropriate number of virtual registers of
@@ -357,7 +358,7 @@ unsigned FunctionLoweringInfo::CreateReg(MVT VT) {
 /// In the case that the given value has struct or array type, this function
 /// will assign registers for each member or element.
 ///
-unsigned FunctionLoweringInfo::CreateRegs(Type *Ty) {
+unsigned FunctionLoweringInfo::CreateRegs(Type *Ty, bool isDivergent) {
   const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
 
   SmallVector<EVT, 4> ValueVTs;
@@ -370,13 +371,18 @@ unsigned FunctionLoweringInfo::CreateRegs(Type *Ty) {
 
     unsigned NumRegs = TLI->getNumRegisters(Ty->getContext(), ValueVT);
     for (unsigned i = 0; i != NumRegs; ++i) {
-      unsigned R = CreateReg(RegisterVT);
+      unsigned R = CreateReg(RegisterVT, isDivergent);
       if (!FirstReg) FirstReg = R;
     }
   }
   return FirstReg;
 }
 
+unsigned FunctionLoweringInfo::CreateRegs(const Value *V) {
+  return CreateRegs(V->getType(), DA && !TLI->requiresUniformRegister(*MF, V) &&
+                                      DA->isDivergent(V));
+}
+
 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the
 /// register is a PHI destination and the PHI's LiveOutInfo is not valid. If
 /// the register's LiveOutInfo is for a smaller bit width, it is extended to
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");
 
diff --git a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.h b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.h
index 3188c2678f1..42f7846fe7c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.h
+++ b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.h
@@ -83,7 +83,7 @@ class LLVM_LIBRARY_VISIBILITY InstrEmitter {
   /// supports SubIdx sub-registers.  Emit a copy if that isn't possible.
   /// Return the virtual register to use.
   unsigned ConstrainForSubReg(unsigned VReg, unsigned SubIdx, MVT VT,
-                              const DebugLoc &DL);
+                              bool isDivergent, const DebugLoc &DL);
 
   /// EmitSubregNode - Generate machine code for subreg nodes.
   ///
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 76e5847ba11..a5274877ece 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -9844,7 +9844,7 @@ SelectionDAGBuilder::HandlePHINodesInSuccessorBlocks(const BasicBlock *LLVMBB) {
       if (const Constant *C = dyn_cast<Constant>(PHIOp)) {
         unsigned &RegOut = ConstantsOut[C];
         if (RegOut == 0) {
-          RegOut = FuncInfo.CreateRegs(C->getType());
+          RegOut = FuncInfo.CreateRegs(C);
           CopyValueToVirtualRegister(C, RegOut);
         }
         Reg = RegOut;
@@ -9857,7 +9857,7 @@ SelectionDAGBuilder::HandlePHINodesInSuccessorBlocks(const BasicBlock *LLVMBB) {
           assert(isa<AllocaInst>(PHIOp) &&
                  FuncInfo.StaticAllocaMap.count(cast<AllocaInst>(PHIOp)) &&
                  "Didn't codegen value into a register!??");
-          Reg = FuncInfo.CreateRegs(PHIOp->getType());
+          Reg = FuncInfo.CreateRegs(PHIOp);
           CopyValueToVirtualRegister(PHIOp, Reg);
         }
       }
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 6c9a1cd646e..6f55f98c51f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -1485,7 +1485,7 @@ void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
               !Inst->use_empty()) {
             unsigned &R = FuncInfo->ValueMap[Inst];
             if (!R)
-              R = FuncInfo->CreateRegs(Inst->getType());
+              R = FuncInfo->CreateRegs(Inst);
           }
 
           bool HadTailCall = false;