diff --git a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
index 5eec0cde118..e2070030797 100644
--- a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -2090,15 +2090,16 @@ AArch64AsmParser::tryParseFPImm(OperandVector &Operands) {
   const AsmToken &Tok = Parser.getTok();
   if (Tok.is(AsmToken::Real)) {
     APFloat RealVal(APFloat::IEEEdouble, Tok.getString());
+    if (isNegative)
+      RealVal.changeSign();
+
     uint64_t IntVal = RealVal.bitcastToAPInt().getZExtValue();
-    // If we had a '-' in front, toggle the sign bit.
-    IntVal ^= (uint64_t)isNegative << 63;
     int Val = AArch64_AM::getFP64Imm(APInt(64, IntVal));
     Parser.Lex(); // Eat the token.
     // Check for out of range values. As an exception, we let Zero through,
     // as we handle that special case in post-processing before matching in
     // order to use the zero register for it.
-    if (Val == -1 && !RealVal.isZero()) {
+    if (Val == -1 && !RealVal.isPosZero()) {
       TokError("expected compatible register or floating-point constant");
       return MatchOperand_ParseFail;
     }
diff --git a/test/MC/AArch64/arm64-fp-encoding-error.s b/test/MC/AArch64/arm64-fp-encoding-error.s
new file mode 100644
index 00000000000..ad301279744
--- /dev/null
+++ b/test/MC/AArch64/arm64-fp-encoding-error.s
@@ -0,0 +1,8 @@
+; RUN: not llvm-mc -triple arm64-apple-ios8.0 %s -o /dev/null 2>&1 | FileCheck %s
+
+        fmov s0, #-0.0
+; CHECK: error: expected compatible register or floating-point constant
+
+        fmov d0, #-0.0
+; CHECK: error: expected compatible register or floating-point constant
+