diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -2656,6 +2656,10 @@
       }
     }
   } else if (IsUnconditionalBranch) {
+    // Treat `call [offset fn_ref]` (or `jmp`) syntax as an error.
+    if (!PtrInOperand && SM.isOffsetOperator())
+      return Error(
+          Start, "`OFFSET` operator cannot be used in an unconditional branch");
     if (PtrInOperand || SM.isBracketUsed())
       MaybeDirectBranchDest = false;
   }
diff --git a/llvm/test/MC/X86/intel-syntax-branch.s b/llvm/test/MC/X86/intel-syntax-branch.s
--- a/llvm/test/MC/X86/intel-syntax-branch.s
+++ b/llvm/test/MC/X86/intel-syntax-branch.s
@@ -61,6 +61,11 @@
 
 .ifdef ERR
 
+  call [offset fn_ref]
+  // ERR-32: {{.*}}.s:[[#@LINE-1]]:8: error: `OFFSET` operator cannot be used in an unconditional branch
+  jmp [offset fn_ref]
+  // ERR-32: {{.*}}.s:[[#@LINE-1]]:7: error: `OFFSET` operator cannot be used in an unconditional branch
+
   call offset fn_ref
   // ERR-32: {{.*}}.s:[[#@LINE-1]]:3: error: invalid operand for instruction
   jmp offset fn_ref