diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -10083,6 +10083,8 @@
 alignment may not be greater than ``1 << 32``. If not specified, or if
 zero, the target can choose to align the allocation on any convenient
 boundary compatible with the type.
+Note that if the ``align`` argument is optional in the textual IR format,
+it is always defined in memory.
 
 '``type``' may be any sized type.
 
@@ -10176,6 +10178,8 @@
 address space. Access of the high bytes can interfere with debugging
 tools, so should not be accessed if the function has the
 ``sanitize_thread`` or ``sanitize_address`` attributes.
+Note that if the ``align`` argument is optional in the textual IR format,
+it is always defined in memory.
 
 The optional ``!nontemporal`` metadata must reference a single
 metadata name ``<nontemp_node>`` corresponding to a metadata node with one
@@ -10316,6 +10320,8 @@
 data race is not allowed. Storing to the extra bytes is not allowed
 even in situations where a data race is known to not exist if the
 function has the ``sanitize_address`` attribute.
+Note that if the ``align`` argument is optional in the textual IR format,
+it is always defined in memory.
 
 The optional ``!nontemporal`` metadata must reference a single metadata
 name ``<nontemp_node>`` corresponding to a metadata node with one ``i32`` entry
@@ -10455,6 +10461,8 @@
 size of the '<value>' type. Note that this default alignment assumption is
 different from the alignment used for the load/store instructions when align
 isn't specified.
+Note that if the ``align`` argument is optional in the textual IR format,
+it is always defined in memory.
 
 The pointer passed into cmpxchg must have alignment greater than or
 equal to the size in memory of the operand.
@@ -10556,6 +10564,8 @@
 size of the '<value>' type. Note that this default alignment assumption is
 different from the alignment used for the load/store instructions when align
 isn't specified.
+Note that if the ``align`` argument is optional in the textual IR format,
+it is always defined in memory.
 
 A ``atomicrmw`` instruction can also take an optional
 ":ref:`syncscope <syncscope>`" argument.