1 files changed, 31 insertions, 0 deletions
diff --git a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
index 063c053ffe8a..38e8b4d9a938 100644
--- a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -699,6 +699,25 @@ public:
     const MCConstantExpr *CE = cast<MCConstantExpr>(Expr);
     return CE->getValue() >= 0 && CE->getValue() <= 0xfff;
   }
+  bool isAddSubImmNeg() const {
+    if (!isShiftedImm() && !isImm())
+      return false;
+
+    const MCExpr *Expr;
+
+    // An ADD/SUB shifter is either 'lsl #0' or 'lsl #12'.
+    if (isShiftedImm()) {
+      unsigned Shift = ShiftedImm.ShiftAmount;
+      Expr = ShiftedImm.Val;
+      if (Shift != 0 && Shift != 12)
+        return false;
+    } else
+      Expr = getImm();
+
+    // Otherwise it should be a real negative immediate in range:
+    const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(Expr);
+    return CE != nullptr && CE->getValue() < 0 && -CE->getValue() <= 0xfff;
+  }
   bool isCondCode() const { return Kind == k_CondCode; }
   bool isSIMDImmType10() const {
     if (!isImm())
@@ -1219,6 +1238,18 @@ public:
     }
   }
 
+  void addAddSubImmNegOperands(MCInst &Inst, unsigned N) const {
+    assert(N == 2 && "Invalid number of operands!");
+
+    const MCExpr *MCE = isShiftedImm() ? getShiftedImmVal() : getImm();
+    const MCConstantExpr *CE = cast<MCConstantExpr>(MCE);
+    int64_t Val = -CE->getValue();
+    unsigned ShiftAmt = isShiftedImm() ? ShiftedImm.ShiftAmount : 0;
+
+    Inst.addOperand(MCOperand::createImm(Val));
+    Inst.addOperand(MCOperand::createImm(ShiftAmt));
+  }
+
   void addCondCodeOperands(MCInst &Inst, unsigned N) const {
     assert(N == 1 && "Invalid number of operands!");
     Inst.addOperand(MCOperand::createImm(getCondCode()));