AArch64AsmParser: tablegen the isBranchTarget helper functions

[SjoerdMeijer]

Summary

Use tablegen to autogenerate isBranchtarget helper functions. This is a cleanup that removes almost identical functions that differ only in a few constants.

[olista01]

lib/Target/AArch64/AArch64InstrFormats.td

279

Instead of listing the minimum and maximum values, could these just be calculated from the bit-width in isBranchTarget?

[SjoerdMeijer]

Thanks for the suggestion: the lower/upper bounds are now also generated.

[olista01]

LGTM

lib/Target/AArch64/AArch64InstrFormats.td

class AsmImmRange<int Low, int High> : AsmOperandClass {
   let PredicateMethod = "isImmInRange<" # Low # "," # High # ">";
 }
 
 def Imm1_8Operand : AsmImmRange<1, 8>;
 def Imm1_16Operand : AsmImmRange<1, 16>;
 def Imm1_32Operand : AsmImmRange<1, 32>;
 def Imm1_64Operand : AsmImmRange<1, 64>;
 
+class BranchTarget<int N> : AsmOperandClass {
+  let Name = "BranchTarget" # N;
+  let DiagnosticType = "InvalidLabel";
+  let PredicateMethod = "isBranchTarget<" # N # ">";
+}
+
+class PCRelLabel<int N> : BranchTarget<N> {
+  let Name = "PCRelLabel" # N;
+}
+
+def BranchTarget14Operand : BranchTarget<14>;
+def BranchTarget26Operand : BranchTarget<26>;
+def PCRelLabel19Operand   : PCRelLabel<19>;
+
 def MovZSymbolG3AsmOperand : AsmOperandClass {
   let Name = "MovZSymbolG3";
   let RenderMethod = "addImmOperands";
 }
 
 def movz_symbol_g3 : Operand<i32> {
   let ParserMatchClass = MovZSymbolG3AsmOperand;
 }
let MCOperandPredicate = [{
     return MCOp.isImm() &&
            MCOp.getImm() != AArch64CC::AL &&
            MCOp.getImm() != AArch64CC::NV;
   }];
 }
 
 // Conditional branch target. 19-bit immediate. The low two bits of the target
 // offset are implied zero and so are not part of the immediate.
-def PCRelLabel19Operand : AsmOperandClass {
-  let Name = "PCRelLabel19";
-  let DiagnosticType = "InvalidLabel";
-}
 def am_brcond : Operand<OtherVT> {
   let EncoderMethod = "getCondBranchTargetOpValue";
   let DecoderMethod = "DecodePCRelLabel19";
   let PrintMethod = "printAlignedLabel";
   let ParserMatchClass = PCRelLabel19Operand;
 }
 
 class BranchCond : I<(outs), (ins ccode:$cond, am_brcond:$target),
multiclass CmpBranch<bit op, string asm, SDNode node> {
   }
 }
 
 //---
 // Test-bit-and-branch instructions.
 //---
 // Test-and-branch target. 14-bit sign-extended immediate. The low two bits of
 // the target offset are implied zero and so are not part of the immediate.
-def BranchTarget14Operand : AsmOperandClass {
-  let Name = "BranchTarget14";
-}
 def am_tbrcond : Operand<OtherVT> {
   let EncoderMethod = "getTestBranchTargetOpValue";
   let PrintMethod = "printAlignedLabel";
   let ParserMatchClass = BranchTarget14Operand;
 }
 
 // AsmOperand classes to emit (or not) special diagnostics
 def TBZImm0_31Operand : AsmOperandClass {
multiclass TestBranch<bit op, string asm, SDNode node> {
   def : Pat<(node GPR64:$Rn, tbz_imm0_31_diag:$imm, bb:$target),
             (!cast<Instruction>(NAME#"W") (EXTRACT_SUBREG GPR64:$Rn, sub_32),
             tbz_imm0_31_diag:$imm, bb:$target)>;
 }
 
 //---
 // Unconditional branch (immediate) instructions.
 //---
-def BranchTarget26Operand : AsmOperandClass {
-  let Name = "BranchTarget26";
-  let DiagnosticType = "InvalidLabel";
-}
 def am_b_target : Operand<OtherVT> {
   let EncoderMethod = "getBranchTargetOpValue";
   let PrintMethod = "printAlignedLabel";
   let ParserMatchClass = BranchTarget26Operand;
 }
 def am_bl_target : Operand<i64> {
   let EncoderMethod = "getBranchTargetOpValue";
   let PrintMethod = "printAlignedLabel";

lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp

bool isSIMDImmType10() const {
     if (!isImm())
       return false;
     const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(getImm());
     if (!MCE)
       return false;
     return AArch64_AM::isAdvSIMDModImmType10(MCE->getValue());
   }
 
-  bool isBranchTarget26() const {
+  template<int N>
+  bool isBranchTarget() const {
     if (!isImm())
       return false;
     const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(getImm());
     if (!MCE)
       return true;
     int64_t Val = MCE->getValue();
     if (Val & 0x3)
       return false;
-    return (Val >= -(0x2000000 << 2) && Val <= (0x1ffffff << 2));
-  }
-
-  bool isPCRelLabel19() const {
-    if (!isImm())
-      return false;
-    const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(getImm());
-    if (!MCE)
-      return true;
-    int64_t Val = MCE->getValue();
-    if (Val & 0x3)
-      return false;
-    return (Val >= -(0x40000 << 2) && Val <= (0x3ffff << 2));
-  }
-
-  bool isBranchTarget14() const {
-    if (!isImm())
-      return false;
-    const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(getImm());
-    if (!MCE)
-      return true;
-    int64_t Val = MCE->getValue();
-    if (Val & 0x3)
-      return false;
-    return (Val >= -(0x2000 << 2) && Val <= (0x1fff << 2));
+    assert(N > 0 && "Branch target immediate cannot be 0 bits!");
+    return (Val >= -((1<<(N-1)) << 2) && Val <= (((1<<(N-1))-1) << 2));
   }
 
   bool
   isMovWSymbol(ArrayRef<AArch64MCExpr::VariantKind> AllowedModifiers) const {
     if (!isImm())
       return false;
 
     AArch64MCExpr::VariantKind ELFRefKind;