Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -130,6 +130,13 @@
 Attribute Changes in Clang
 --------------------------
 
+- When a non-variadic function is decorated with the ``format`` attribute,
+  Clang now checks that the format string would match the function's parameters'
+  types after default argument promotion. As a result, it's no longer an
+  automatic diagnostic to use parameters of types that the format style
+  supports but that are never the result of default argument promotion, such as
+  ``float``. (`#59824: <https://github.com/llvm/llvm-project/issues/59824>`_)
+
 Improvements to Clang's diagnostics
 -----------------------------------
 - Clang constexpr evaluator now prints template arguments when displaying
Index: clang/lib/AST/FormatString.cpp
===================================================================
--- clang/lib/AST/FormatString.cpp
+++ clang/lib/AST/FormatString.cpp
@@ -458,6 +458,10 @@
             switch (BT->getKind()) {
             default:
               break;
+            case BuiltinType::Bool:
+              if (T == C.IntTy || T == C.UnsignedIntTy)
+                return MatchPromotion;
+              break;
             case BuiltinType::Int:
             case BuiltinType::UInt:
               if (T == C.SignedCharTy || T == C.UnsignedCharTy ||
@@ -465,6 +469,24 @@
                   T == C.WideCharTy)
                 return MatchPromotion;
               break;
+            case BuiltinType::Char_U:
+              if (T == C.UnsignedIntTy)
+                return MatchPromotion;
+              if (T == C.UnsignedShortTy)
+                return NoMatchPromotionTypeConfusion;
+              break;
+            case BuiltinType::Char_S:
+              if (T == C.IntTy)
+                return MatchPromotion;
+              if (T == C.ShortTy)
+                return NoMatchPromotionTypeConfusion;
+              break;
+            case BuiltinType::Half:
+            case BuiltinType::Float16:
+            case BuiltinType::Float:
+              if (T == C.DoubleTy)
+                return MatchPromotion;
+              break;
             case BuiltinType::Short:
             case BuiltinType::UShort:
               if (T == C.SignedCharTy || T == C.UnsignedCharTy)
Index: clang/test/Sema/attr-format.c
===================================================================
--- clang/test/Sema/attr-format.c
+++ clang/test/Sema/attr-format.c
@@ -94,13 +94,9 @@
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
 }
 
-__attribute__((format(printf, 1, 2))) void forward_fixed(const char *fmt, int i) { // expected-warning{{GCC requires a function with the 'format' attribute to be variadic}}
-  forward_fixed(fmt, i);
-  a(fmt, i);
-}
-
-__attribute__((format(printf, 1, 2))) void forward_fixed_2(const char *fmt, int i, int j) { // expected-warning{{GCC requires a function with the 'format' attribute to be variadic}}
-  forward_fixed_2(fmt, i, j);
-  a(fmt, i);
+__attribute__((format(printf, 1, 2)))
+void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, double m) { // expected-warning{{GCC requires a function with the 'format' attribute to be variadic}}
+  forward_fixed(fmt, b, i, j, k, l, m);
+  a(fmt, b, i, j, k, l, m);
 }
 
Index: clang/test/SemaCXX/attr-format.cpp
===================================================================
--- clang/test/SemaCXX/attr-format.cpp
+++ clang/test/SemaCXX/attr-format.cpp
@@ -72,12 +72,20 @@
   int x = 123;
   int &y = x;
   const char *s = "world";
+  bool b = false;
   format("bare string");
   format("%s", 123); // expected-warning{{format specifies type 'char *' but the argument has type 'int'}}
   format("%s %s %u %d %i %p\n", "hello", s, 10u, x, y, &do_format);
   format("%s %s %u %d %i %p\n", "hello", s, 10u, x, y, do_format);
   format("bad format %s"); // expected-warning{{more '%' conversions than data arguments}}
 
+  format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
+  format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 'long double' but the argument has type '__fp16'}}
+  format("%Lf", 123.f); // expected-warning{{format specifies type 'long double' but the argument has type 'float'}}
+  format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
+  format("%li", b); // expected-warning{{format specifies type 'long' but the argument has type 'bool'}}
+
   struct foo f;
   format_invalid_nonpod("hello %i", f); // expected-warning{{format specifies type 'int' but the argument has type 'struct foo'}}