diff --git a/util/fipstools/delocate/delocate.go b/util/fipstools/delocate/delocate.go
index f8573e3055b..d7ae588d2fb 100644
--- a/util/fipstools/delocate/delocate.go
+++ b/util/fipstools/delocate/delocate.go
@@ -1380,6 +1380,13 @@ Args:
 		case ruleRegisterOrConstant, ruleLocalLabelRef:
 			args = append(args, d.contents(fullArg))
 
+		// The AVX-512 mask register is appended to its
+		// preceding `RegisterOrConstant` without whitespace
+		// or a comma.
+		case ruleAVX512Token:
+			tail := &args[len(args)-1];
+			*tail += d.contents(fullArg);
+
 		case ruleMemoryRef:
 			symbol, offset, section, didChange, symbolIsLocal, memRef := d.parseMemRef(arg.up)
 			changed = didChange
diff --git a/util/fipstools/delocate/delocate.peg b/util/fipstools/delocate/delocate.peg
index 8900af05cc2..0b83eca6a50 100644
--- a/util/fipstools/delocate/delocate.peg
+++ b/util/fipstools/delocate/delocate.peg
@@ -72,7 +72,7 @@ LocalLabel <- [0-9][0-9$]*
 LocalLabelRef <- [0-9][0-9$]*[bf]
 Instruction <- InstructionName (WS InstructionArg ((WS? ','? WS?) InstructionArg)*)?
 InstructionName <- [[A-Z]][[A-Z.0-9]]* [.+\-]?
-InstructionArg <- IndirectionIndicator? (ARMConstantTweak / RegisterOrConstant / LocalLabelRef / TOCRefHigh / TOCRefLow / GOTLocation / GOTSymbolOffset / MemoryRef) AVX512Token*
+InstructionArg <- IndirectionIndicator? (ARMConstantTweak / RegisterOrConstant / LocalLabelRef / TOCRefHigh / TOCRefLow / GOTLocation / GOTSymbolOffset / MemoryRef / AVX512Token)
 GOTLocation <- '$_GLOBAL_OFFSET_TABLE_-' LocalSymbol
 GOTSymbolOffset <- ('$' SymbolName '@GOT' 'OFF'?) / (":got:" SymbolName)
 AVX512Token <- WS? '{' '%'? [0-9a-z]* '}'