diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -13363,6 +13363,13 @@
   if (InRange && IsEnumConstOrFromMacro(S, Constant))
     return false;
 
+  // Don't warn if the comparison involves the 'size_t' type.
+  QualType SizeT = S.Context.getSizeType();
+  if (S.Context.hasSameType(Constant->getType().getCanonicalType(), SizeT) &&
+      S.Context.hasSameType(Other->getType().getCanonicalType(), SizeT)) {
+    return false;
+  }
+
   // A comparison of an unsigned bit-field against 0 is really a type problem,
   // even though at the type level the bit-field might promote to 'signed int'.
   if (Other->refersToBitField() && InRange && Value == 0 &&