diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 6604ec60d9ba..4999e619ecd0 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -2635,7 +2635,7 @@ For example:
     This attribute indicates that outlining passes should not modify the
     function.
 
-``"modular-format"="<string_idx>,<first_idx_to_check>,<modular_impl_fn>,<impl_name>,<aspects...>"``
+``"modular-format"="<type>,<string_idx>,<first_idx_to_check>,<modular_impl_fn>,<impl_name>,<aspects...>"``
     This attribute indicates that the implementation is modular on a particular
     format string argument . When the argument for a given call is constant, the
     compiler may redirect the call to a modular implementation function
@@ -2648,13 +2648,15 @@ For example:
     brought into the link to satisfy weak references in the modular
     implemenation function.
 
-    The first two arguments have the same semantics as the arguments to the C
+    The first three arguments have the same semantics as the arguments to the C
     ``format`` attribute.
 
     The following aspects are currently supported:
 
     - ``float``: The call has a floating point argument
 
+
+
 Call Site Attributes
 ----------------------
 
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 83aa79899710..0e102175cbb4 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -4008,18 +4008,18 @@ static Value *optimizeModularFormat(CallInst *CI, IRBuilderBase &B) {
 
   SmallVector<StringRef> Args(
       llvm::split(CI->getFnAttr("modular-format").getValueAsString(), ','));
-  // TODO: Examine the format argument in Args[0].
+  // TODO: Make use of the first two arguments
   // TODO: Error handling
   unsigned FirstArgIdx;
-  if (!llvm::to_integer(Args[1], FirstArgIdx))
+  if (!llvm::to_integer(Args[2], FirstArgIdx))
     return nullptr;
   if (FirstArgIdx == 0)
     return nullptr;
   --FirstArgIdx;
-  StringRef FnName = Args[2];
-  StringRef ImplName = Args[3];
+  StringRef FnName = Args[3];
+  StringRef ImplName = Args[4];
   DenseSet<StringRef> Aspects(llvm::from_range,
-                              ArrayRef<StringRef>(Args).drop_front(4));
+                              ArrayRef<StringRef>(Args).drop_front(5));
   Module *M = CI->getModule();
   LLVMContext &Ctx = M->getContext();
   Function *Callee = CI->getCalledFunction();