Index: llvm/lib/MC/MCParser/AsmParser.cpp
===================================================================
--- llvm/lib/MC/MCParser/AsmParser.cpp
+++ llvm/lib/MC/MCParser/AsmParser.cpp
@@ -3354,6 +3354,10 @@
   if (parseEOL())
     return true;
 
+  if (FillSize == 0) {
+    Warning(SizeLoc, "'.fill' directive with 0 size has no effect");
+    return false;
+  }
   if (FillSize < 0) {
     Warning(SizeLoc, "'.fill' directive with negative size has no effect");
     return false;
Index: llvm/test/MC/AsmParser/directive_fill.s
===================================================================
--- llvm/test/MC/AsmParser/directive_fill.s
+++ llvm/test/MC/AsmParser/directive_fill.s
@@ -77,3 +77,6 @@
 TEST13:
 	.fill TEST11 - TEST12+i, 4, 0x12345678
 
+# CHECK-WARNINGS: '.fill' directive with 0 size has no effect
+TEST14:
+	.fill 1, 0