[RISCV] Cleanup assembler predicates after #133377. (#133652)

Make isSImm12 look more like isUImm20LUI.
Move variables closer to their use.
Fold some function calls into if statements.

Author: topperc

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

@@ -555,50 +555,55 @@ struct RISCVOperand final : public MCParsedAsmOperand {
 
   bool isBareSymbol() const {
     int64_t Imm;
-    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     // Must be of 'immediate' type but not a constant.
     if (!isImm() || evaluateConstantImm(getImm(), Imm))
       return false;
+
+    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     return RISCVAsmParser::classifySymbolRef(getImm(), VK) &&
            VK == RISCVMCExpr::VK_None;
   }
 
   bool isCallSymbol() const {
     int64_t Imm;
-    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     // Must be of 'immediate' type but not a constant.
     if (!isImm() || evaluateConstantImm(getImm(), Imm))
       return false;
+
+    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     return RISCVAsmParser::classifySymbolRef(getImm(), VK) &&
            (VK == RISCVMCExpr::VK_CALL || VK == RISCVMCExpr::VK_CALL_PLT);
   }
 
   bool isPseudoJumpSymbol() const {
     int64_t Imm;
-    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     // Must be of 'immediate' type but not a constant.
     if (!isImm() || evaluateConstantImm(getImm(), Imm))
       return false;
+
+    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     return RISCVAsmParser::classifySymbolRef(getImm(), VK) &&
            VK == RISCVMCExpr::VK_CALL;
   }
 
   bool isTPRelAddSymbol() const {
     int64_t Imm;
-    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     // Must be of 'immediate' type but not a constant.
     if (!isImm() || evaluateConstantImm(getImm(), Imm))
       return false;
+
+    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     return RISCVAsmParser::classifySymbolRef(getImm(), VK) &&
            VK == RISCVMCExpr::VK_TPREL_ADD;
   }
 
   bool isTLSDESCCallSymbol() const {
     int64_t Imm;
-    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     // Must be of 'immediate' type but not a constant.
     if (!isImm() || evaluateConstantImm(getImm(), Imm))
       return false;
+
+    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     return RISCVAsmParser::classifySymbolRef(getImm(), VK) &&
            VK == RISCVMCExpr::VK_TLSDESC_CALL;
   }
@@ -838,19 +843,17 @@ struct RISCVOperand final : public MCParsedAsmOperand {
   }
 
   bool isSImm12() const {
-    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
-    int64_t Imm;
-    bool IsValid;
     if (!isImm())
       return false;
-    bool IsConstantImm = evaluateConstantImm(getImm(), Imm);
-    if (!IsConstantImm)
-      IsValid = RISCVAsmParser::classifySymbolRef(getImm(), VK);
-    else
-      IsValid = isInt<12>(fixImmediateForRV32(Imm, isRV64Imm()));
-    return IsValid &&
-           (IsConstantImm || VK == RISCVMCExpr::VK_LO ||
-            VK == RISCVMCExpr::VK_PCREL_LO || VK == RISCVMCExpr::VK_TPREL_LO ||
+
+    int64_t Imm;
+    if (evaluateConstantImm(getImm(), Imm))
+      return isInt<12>(fixImmediateForRV32(Imm, isRV64Imm()));
+
+    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
+    return RISCVAsmParser::classifySymbolRef(getImm(), VK) &&
+           (VK == RISCVMCExpr::VK_LO || VK == RISCVMCExpr::VK_PCREL_LO ||
+            VK == RISCVMCExpr::VK_TPREL_LO ||
             VK == RISCVMCExpr::VK_TLSDESC_LOAD_LO ||
             VK == RISCVMCExpr::VK_TLSDESC_ADD_LO);
   }
@@ -873,26 +876,27 @@ struct RISCVOperand final : public MCParsedAsmOperand {
   }
 
   bool isUImm20LUI() const {
-    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
-    int64_t Imm;
     if (!isImm())
       return false;
-    bool IsConstantImm = evaluateConstantImm(getImm(), Imm);
-    if (IsConstantImm)
+
+    int64_t Imm;
+    if (evaluateConstantImm(getImm(), Imm))
       return isUInt<20>(Imm);
+
+    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     return RISCVAsmParser::classifySymbolRef(getImm(), VK) &&
            (VK == RISCVMCExpr::VK_HI || VK == RISCVMCExpr::VK_TPREL_HI);
   }
 
   bool isUImm20AUIPC() const {
-    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
-    int64_t Imm;
     if (!isImm())
       return false;
-    bool IsConstantImm = evaluateConstantImm(getImm(), Imm);
-    if (IsConstantImm)
+
+    int64_t Imm;
+    if (evaluateConstantImm(getImm(), Imm))
       return isUInt<20>(Imm);
 
+    RISCVMCExpr::Specifier VK = RISCVMCExpr::VK_None;
     return RISCVAsmParser::classifySymbolRef(getImm(), VK) &&
            (VK == RISCVMCExpr::VK_PCREL_HI || VK == RISCVMCExpr::VK_GOT_HI ||
             VK == RISCVMCExpr::VK_TLS_GOT_HI ||