[AArch64][SVE] Asm: Print indexed element 0 as FPR.

Print the first indexed element as a FP register, for example:

  mov z0.d, z1.d[0]

Is now printed as:

  mov z0.d, d1

Next to printing, this patch also adds aliases to parse 'mov z0.d, d1'.

Reviewers: rengolin, fhahn, samparker, SjoerdMeijer, javed.absar

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D47571

llvm-svn: 333872
diff --git a/llvm/lib/Target/AArch64/AArch64RegisterInfo.td b/llvm/lib/Target/AArch64/AArch64RegisterInfo.td
index 7acdb69..182451c 100644
--- a/llvm/lib/Target/AArch64/AArch64RegisterInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64RegisterInfo.td
@@ -859,6 +859,22 @@
 def ZPR64   : ZPRRegOp<"d", ZPRAsmOp64,  ZPR>;
 def ZPR128  : ZPRRegOp<"q", ZPRAsmOp128, ZPR>;
 
+class FPRasZPR<int Width> : AsmOperandClass{
+  let Name = "FPR" # Width # "asZPR";
+  let PredicateMethod = "isFPRasZPR<AArch64::FPR" # Width # "RegClassID>";
+  let RenderMethod = "addFPRasZPRRegOperands<" # Width # ">";
+}
+
+class FPRasZPROperand<int Width> : RegisterOperand<ZPR> {
+  let ParserMatchClass = FPRasZPR<Width>;
+  let PrintMethod = "printZPRasFPR<" # Width # ">";
+}
+
+def FPR8asZPR   : FPRasZPROperand<8>;
+def FPR16asZPR  : FPRasZPROperand<16>;
+def FPR32asZPR  : FPRasZPROperand<32>;
+def FPR64asZPR  : FPRasZPROperand<64>;
+def FPR128asZPR : FPRasZPROperand<128>;
 
 let Namespace = "AArch64" in {
   def zsub0 : SubRegIndex<128, -1>;
diff --git a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
index cf22a1c..b6dd39c 100644
--- a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -934,6 +934,11 @@
            AArch64MCRegisterClasses[Class].contains(getReg());
   }
 
+  template <unsigned Class> bool isFPRasZPR() const {
+    return Kind == k_Register && Reg.Kind == RegKind::Scalar &&
+           AArch64MCRegisterClasses[Class].contains(getReg());
+  }
+
   template <int ElementWidth, unsigned Class>
   DiagnosticPredicate isSVEPredicateVectorRegOfWidth() const {
     if (Kind != k_Register || Reg.Kind != RegKind::SVEPredicateVector)
@@ -1269,6 +1274,21 @@
     Inst.addOperand(MCOperand::createReg(Reg));
   }
 
+  template <int Width>
+  void addFPRasZPRRegOperands(MCInst &Inst, unsigned N) const {
+    unsigned Base;
+    switch (Width) {
+    case 8:   Base = AArch64::B0; break;
+    case 16:  Base = AArch64::H0; break;
+    case 32:  Base = AArch64::S0; break;
+    case 64:  Base = AArch64::D0; break;
+    case 128: Base = AArch64::Q0; break;
+    default:
+      llvm_unreachable("Unsupported width");
+    }
+    Inst.addOperand(MCOperand::createReg(AArch64::Z0 + getReg() - Base));
+  }
+
   void addVectorReg64Operands(MCInst &Inst, unsigned N) const {
     assert(N == 1 && "Invalid number of operands!");
     assert(
diff --git a/llvm/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.cpp b/llvm/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.cpp
index 67584d1..3d52fa1 100644
--- a/llvm/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.cpp
+++ b/llvm/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.cpp
@@ -1499,3 +1499,21 @@
   else
     O << '#' << formatHex((uint64_t)PrintVal);
 }
+
+template <int Width>
+void AArch64InstPrinter::printZPRasFPR(const MCInst *MI, unsigned OpNum,
+                                       const MCSubtargetInfo &STI,
+                                       raw_ostream &O) {
+  unsigned Base;
+  switch (Width) {
+  case 8:   Base = AArch64::B0; break;
+  case 16:  Base = AArch64::H0; break;
+  case 32:  Base = AArch64::S0; break;
+  case 64:  Base = AArch64::D0; break;
+  case 128: Base = AArch64::Q0; break;
+  default:
+    llvm_unreachable("Unsupported width");
+  }
+  unsigned Reg = MI->getOperand(OpNum).getReg();
+  O << getRegisterName(Reg - AArch64::Z0 + Base);
+}
diff --git a/llvm/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.h b/llvm/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.h
index ca10830..446a065 100644
--- a/llvm/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.h
+++ b/llvm/lib/Target/AArch64/InstPrinter/AArch64InstPrinter.h
@@ -180,6 +180,9 @@
   template <char = 0>
   void printSVERegOp(const MCInst *MI, unsigned OpNum,
                     const MCSubtargetInfo &STI, raw_ostream &O);
+  template <int Width>
+  void printZPRasFPR(const MCInst *MI, unsigned OpNum,
+                     const MCSubtargetInfo &STI, raw_ostream &O);
 };
 
 class AArch64AppleInstPrinter : public AArch64InstPrinter {
diff --git a/llvm/lib/Target/AArch64/SVEInstrFormats.td b/llvm/lib/Target/AArch64/SVEInstrFormats.td
index 757bb6f..9382473 100644
--- a/llvm/lib/Target/AArch64/SVEInstrFormats.td
+++ b/llvm/lib/Target/AArch64/SVEInstrFormats.td
@@ -334,6 +334,16 @@
                   (!cast<Instruction>(NAME # _D) ZPR64:$Zd, ZPR64:$Zn, sve_elm_idx_extdup_d:$idx), 1>;
   def : InstAlias<"mov $Zd, $Zn$idx",
                   (!cast<Instruction>(NAME # _Q) ZPR128:$Zd, ZPR128:$Zn, sve_elm_idx_extdup_q:$idx), 1>;
+  def : InstAlias<"mov $Zd, $Bn",
+                  (!cast<Instruction>(NAME # _B) ZPR8:$Zd, FPR8asZPR:$Bn, 0), 2>;
+  def : InstAlias<"mov $Zd, $Hn",
+                  (!cast<Instruction>(NAME # _H) ZPR16:$Zd, FPR16asZPR:$Hn, 0), 2>;
+  def : InstAlias<"mov $Zd, $Sn",
+                  (!cast<Instruction>(NAME # _S) ZPR32:$Zd, FPR32asZPR:$Sn, 0), 2>;
+  def : InstAlias<"mov $Zd, $Dn",
+                  (!cast<Instruction>(NAME # _D) ZPR64:$Zd, FPR64asZPR:$Dn, 0), 2>;
+  def : InstAlias<"mov $Zd, $Qn",
+                  (!cast<Instruction>(NAME # _Q) ZPR128:$Zd, FPR128asZPR:$Qn, 0), 2>;
 }
 
 //===----------------------------------------------------------------------===//