R600/SI: Fix int_SI_fs_interp_constant

The important fix is that the constant interpolation value is stored in the
parameter slot P0, which is encoded as 2.

In addition, drop the SI_INTERP_CONST pseudo instruction, pass the parameter
slot as an operand to V_INTERP_MOV_F32 instead of hardcoding it there, and
add a special operand class for the parameter slots for type checking and
pretty printing.

NOTE: This is a candidate for the Mesa stable branch.

Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175193 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 97eba4246d0c41dd718ffff1e0f4011c986c2fe8)

5 files changed, 34 insertions, 37 deletions

diff --git a/lib/Target/R600/InstPrinter/AMDGPUInstPrinter.cpp b/lib/Target/R600/InstPrinter/AMDGPUInstPrinter.cpp
index fb17ab7ddf4..d6450a0fab9 100644
--- a/lib/Target/R600/InstPrinter/AMDGPUInstPrinter.cpp
+++ b/lib/Target/R600/InstPrinter/AMDGPUInstPrinter.cpp
@@ -40,6 +40,21 @@ void AMDGPUInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
   }
 }
 
+void AMDGPUInstPrinter::printInterpSlot(const MCInst *MI, unsigned OpNum,
+                                        raw_ostream &O) {
+  unsigned Imm = MI->getOperand(OpNum).getImm();
+
+  if (Imm == 2) {
+    O << "P0";
+  } else if (Imm == 1) {
+    O << "P20";
+  } else if (Imm == 0) {
+    O << "P10";
+  } else {
+    assert(!"Invalid interpolation parameter slot");
+  }
+}
+
 void AMDGPUInstPrinter::printMemOperand(const MCInst *MI, unsigned OpNo,
                                         raw_ostream &O) {
   printOperand(MI, OpNo, O);
diff --git a/lib/Target/R600/InstPrinter/AMDGPUInstPrinter.h b/lib/Target/R600/InstPrinter/AMDGPUInstPrinter.h
index e775c4c82e7..767a7082cc2 100644
--- a/lib/Target/R600/InstPrinter/AMDGPUInstPrinter.h
+++ b/lib/Target/R600/InstPrinter/AMDGPUInstPrinter.h
@@ -33,6 +33,7 @@ public:
 
 private:
   void printOperand(const MCInst *MI, unsigned OpNo, raw_ostream &O);
+  void printInterpSlot(const MCInst *MI, unsigned OpNum, raw_ostream &O);
   void printMemOperand(const MCInst *MI, unsigned OpNo, raw_ostream &O);
   void printIfSet(const MCInst *MI, unsigned OpNo, raw_ostream &O, StringRef Asm);
   void printAbs(const MCInst *MI, unsigned OpNo, raw_ostream &O);
diff --git a/lib/Target/R600/SIISelLowering.cpp b/lib/Target/R600/SIISelLowering.cpp
index 87cf5962898..3865d4f34b2 100644
--- a/lib/Target/R600/SIISelLowering.cpp
+++ b/lib/Target/R600/SIISelLowering.cpp
@@ -120,9 +120,6 @@ MachineBasicBlock * SITargetLowering::EmitInstrWithCustomInserter(
   case AMDGPU::SI_INTERP:
     LowerSI_INTERP(MI, *BB, I, MRI);
     break;
-  case AMDGPU::SI_INTERP_CONST:
-    LowerSI_INTERP_CONST(MI, *BB, I, MRI);
-    break;
   case AMDGPU::SI_WQM:
     LowerSI_WQM(MI, *BB, I, MRI);
     break;
@@ -172,27 +169,6 @@ void SITargetLowering::LowerSI_INTERP(MachineInstr *MI, MachineBasicBlock &BB,
   MI->eraseFromParent();
 }
 
-void SITargetLowering::LowerSI_INTERP_CONST(MachineInstr *MI,
-    MachineBasicBlock &BB, MachineBasicBlock::iterator I,
-    MachineRegisterInfo &MRI) const {
-  MachineOperand dst = MI->getOperand(0);
-  MachineOperand attr_chan = MI->getOperand(1);
-  MachineOperand attr = MI->getOperand(2);
-  MachineOperand params = MI->getOperand(3);
-  unsigned M0 = MRI.createVirtualRegister(&AMDGPU::M0RegRegClass);
-
-  BuildMI(BB, I, BB.findDebugLoc(I), TII->get(AMDGPU::S_MOV_B32), M0)
-          .addOperand(params);
-
-  BuildMI(BB, I, BB.findDebugLoc(I), TII->get(AMDGPU::V_INTERP_MOV_F32))
-          .addOperand(dst)
-          .addOperand(attr_chan)
-          .addOperand(attr)
-          .addReg(M0);
-
-  MI->eraseFromParent();
-}
-
 void SITargetLowering::LowerSI_V_CNDLT(MachineInstr *MI, MachineBasicBlock &BB,
     MachineBasicBlock::iterator I, MachineRegisterInfo & MRI) const {
   unsigned VCC = MRI.createVirtualRegister(&AMDGPU::SReg_64RegClass);
diff --git a/lib/Target/R600/SIISelLowering.h b/lib/Target/R600/SIISelLowering.h
index 8528c24a3ce..f4bc94da40e 100644
--- a/lib/Target/R600/SIISelLowering.h
+++ b/lib/Target/R600/SIISelLowering.h
@@ -27,8 +27,6 @@ class SITargetLowering : public AMDGPUTargetLowering {
               MachineBasicBlock::iterator I, unsigned Opocde) const;
   void LowerSI_INTERP(MachineInstr *MI, MachineBasicBlock &BB,
               MachineBasicBlock::iterator I, MachineRegisterInfo & MRI) const;
-  void LowerSI_INTERP_CONST(MachineInstr *MI, MachineBasicBlock &BB,
-              MachineBasicBlock::iterator I, MachineRegisterInfo &MRI) const;
   void LowerSI_WQM(MachineInstr *MI, MachineBasicBlock &BB,
               MachineBasicBlock::iterator I, MachineRegisterInfo & MRI) const;
   void LowerSI_V_CNDLT(MachineInstr *MI, MachineBasicBlock &BB,
diff --git a/lib/Target/R600/SIInstructions.td b/lib/Target/R600/SIInstructions.td
index a09f24378ee..b1533bd30e6 100644
--- a/lib/Target/R600/SIInstructions.td
+++ b/lib/Target/R600/SIInstructions.td
@@ -11,6 +11,17 @@
 // that are not yet supported remain commented out.
 //===----------------------------------------------------------------------===//
 
+class InterpSlots {
+int P0 = 2;
+int P10 = 0;
+int P20 = 1;
+}
+def INTERP : InterpSlots;
+
+def InterpSlot : Operand<i32> {
+  let PrintMethod = "printInterpSlot";
+}
+
 def isSI : Predicate<"Subtarget.device()"
                             "->getGeneration() == AMDGPUDeviceInfo::HD7XXX">;
 
@@ -681,10 +692,9 @@ def V_INTERP_P2_F32 : VINTRP <
 def V_INTERP_MOV_F32 : VINTRP <
   0x00000002,
   (outs VReg_32:$dst),
-  (ins i32imm:$attr_chan, i32imm:$attr, M0Reg:$m0),
-  "V_INTERP_MOV_F32",
+  (ins InterpSlot:$src0, i32imm:$attr_chan, i32imm:$attr, M0Reg:$m0),
+  "V_INTERP_MOV_F32 $dst, $src0, $attr_chan, $attr",
   []> {
-  let VSRC = 0;
   let DisableEncoding = "$m0";
 }
 
@@ -1079,14 +1089,6 @@ def SI_INTERP : InstSI <
   []
 >;
 
-def SI_INTERP_CONST : InstSI <
-  (outs VReg_32:$dst),
-  (ins i32imm:$attr_chan, i32imm:$attr, SReg_32:$params),
-  "SI_INTERP_CONST $dst, $attr_chan, $attr, $params",
-  [(set VReg_32:$dst, (int_SI_fs_interp_constant imm:$attr_chan,
-                                                 imm:$attr, SReg_32:$params))]
->;
-
 def SI_WQM : InstSI <
   (outs),
   (ins),
@@ -1322,6 +1324,11 @@ def : Pat <
 /********** ===================== **********/
 
 def : Pat <
+  (int_SI_fs_interp_constant imm:$attr_chan, imm:$attr, SReg_32:$params),
+  (V_INTERP_MOV_F32 INTERP.P0, imm:$attr_chan, imm:$attr, SReg_32:$params)
+>;
+
+def : Pat <
   (int_SI_fs_interp_linear_center imm:$attr_chan, imm:$attr, SReg_32:$params),
   (SI_INTERP (f32 LINEAR_CENTER_I), (f32 LINEAR_CENTER_J), imm:$attr_chan,
              imm:$attr, SReg_32:$params)