diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -1341,6 +1341,7 @@
           }
         }
       }
+      assert(inputSections.size() < UNSPECIFIED_INPUT_ORDER);
     }
 
     if (config->deadStrip)
diff --git a/lld/MachO/OutputSection.h b/lld/MachO/OutputSection.h
--- a/lld/MachO/OutputSection.h
+++ b/lld/MachO/OutputSection.h
@@ -20,6 +20,12 @@
 class InputSection;
 class OutputSegment;
 
+// The default order value for OutputSections that are not constructed from
+// InputSections (i.e. SyntheticSections). We make it less than INT_MAX in order
+// not to conflict with the ordering of zerofill sections, which must always be
+// placed at the end of their segment.
+constexpr int UNSPECIFIED_INPUT_ORDER = std::numeric_limits<int>::max() - 1024;
+
 // Output sections represent the finalized sections present within the final
 // linked executable. They can represent special sections (like the symbol
 // table), or represent coalesced sections from the various inputs given to the
@@ -61,7 +67,7 @@
   // For output sections that don't have explicit ordering requirements, their
   // output order should be based on the order of the input sections they
   // contain.
-  int inputOrder = std::numeric_limits<int>::max();
+  int inputOrder = UNSPECIFIED_INPUT_ORDER;
 
   uint32_t index = 0;
   uint64_t addr = 0;
diff --git a/lld/MachO/OutputSegment.h b/lld/MachO/OutputSegment.h
--- a/lld/MachO/OutputSegment.h
+++ b/lld/MachO/OutputSegment.h
@@ -51,7 +51,7 @@
   uint64_t fileOff = 0;
   uint64_t fileSize = 0;
   uint64_t vmSize = 0;
-  int inputOrder = std::numeric_limits<int>::max();
+  int inputOrder = UNSPECIFIED_INPUT_ORDER;
   StringRef name;
   uint32_t maxProt = 0;
   uint32_t initProt = 0;