[basic.atomics] Use math mode for memory model placeholders.

source/atomics.tex

@@ -419,78 +419,78 @@
 \end{note}
 
 \pnum
-An atomic operation \placeholder{A} that performs a release operation on an atomic
-object \placeholder{M} synchronizes with an atomic operation \placeholder{B} that performs
-an acquire operation on \placeholder{M} and takes its value from any side effect in the
-release sequence headed by \placeholder{A}.
+An atomic operation $A$ that performs a release operation on an atomic
+object $M$ synchronizes with an atomic operation $B$ that performs
+an acquire operation on $M$ and takes its value from any side effect in the
+release sequence headed by $A$.
 
 \pnum
-An atomic operation \placeholder{A} on some atomic object \placeholder{M} is
+An atomic operation $A$ on some atomic object $M$ is
 \defn{coherence-ordered before}
-another atomic operation \placeholder{B} on \placeholder{M} if
+another atomic operation $B$ on $M$ if
 \begin{itemize}
-\item \placeholder{A} is a modification, and
-\placeholder{B} reads the value stored by \placeholder{A}, or
-\item \placeholder{A} precedes \placeholder{B}
-in the modification order of \placeholder{M}, or
-\item \placeholder{A} and \placeholder{B} are not
+\item $A$ is a modification, and
+$B$ reads the value stored by $A$, or
+\item $A$ precedes $B$
+in the modification order of $M$, or
+\item $A$ and $B$ are not
 the same atomic read-modify-write operation, and
-there exists an atomic modification \placeholder{X} of \placeholder{M}
-such that \placeholder{A} reads the value stored by \placeholder{X} and
-\placeholder{X} precedes \placeholder{B}
-in the modification order of \placeholder{M}, or
-\item there exists an atomic modification \placeholder{X} of \placeholder{M}
-such that \placeholder{A} is coherence-ordered before \placeholder{X} and
-\placeholder{X} is coherence-ordered before \placeholder{B}.
+there exists an atomic modification $X$ of $M$
+such that $A$ reads the value stored by $X$ and
+$X$ precedes $B$
+in the modification order of $M$, or
+\item there exists an atomic modification $X$ of $M$
+such that $A$ is coherence-ordered before $X$ and
+$X$ is coherence-ordered before $B$.
 \end{itemize}
 
 \pnum
-There is a single total order \placeholder{S}
+There is a single total order $S$
 on all \tcode{memory_order::seq_cst} operations, including fences,
 that satisfies the following constraints.
-First, if \placeholder{A} and \placeholder{B} are
+First, if $A$ and $B$ are
 \tcode{memory_order::seq_cst} operations and
-\placeholder{A} strongly happens before \placeholder{B},
-then \placeholder{A} precedes \placeholder{B} in \placeholder{S}.
-Second, for every pair of atomic operations \placeholder{A} and
-\placeholder{B} on an object \placeholder{M},
-where \placeholder{A} is coherence-ordered before \placeholder{B},
-the following four conditions are required to be satisfied by \placeholder{S}:
+$A$ strongly happens before $B$,
+then $A$ precedes $B$ in $S$.
+Second, for every pair of atomic operations $A$ and
+$B$ on an object $M$,
+where $A$ is coherence-ordered before $B$,
+the following four conditions are required to be satisfied by $S$:
 \begin{itemize}
-\item if \placeholder{A} and \placeholder{B} are both
+\item if $A$ and $B$ are both
 \tcode{memory_order::seq_cst} operations,
-then \placeholder{A} precedes \placeholder{B} in \placeholder{S}; and
-\item if \placeholder{A} is a \tcode{memory_order::seq_cst} operation and
-\placeholder{B} happens before
-a \tcode{memory_order::seq_cst} fence \placeholder{Y},
-then \placeholder{A} precedes \placeholder{Y} in \placeholder{S}; and
-\item if a \tcode{memory_order::seq_cst} fence \placeholder{X}
-happens before \placeholder{A} and
-\placeholder{B} is a \tcode{memory_order::seq_cst} operation,
-then \placeholder{X} precedes \placeholder{B} in \placeholder{S}; and
-\item if a \tcode{memory_order::seq_cst} fence \placeholder{X}
-happens before \placeholder{A} and
-\placeholder{B} happens before
-a \tcode{memory_order::seq_cst} fence \placeholder{Y},
-then \placeholder{X} precedes \placeholder{Y} in \placeholder{S}.
+then $A$ precedes $B$ in $S$; and
+\item if $A$ is a \tcode{memory_order::seq_cst} operation and
+$B$ happens before
+a \tcode{memory_order::seq_cst} fence $Y$,
+then $A$ precedes $Y$ in $S$; and
+\item if a \tcode{memory_order::seq_cst} fence $X$
+happens before $A$ and
+$B$ is a \tcode{memory_order::seq_cst} operation,
+then $X$ precedes $B$ in $S$; and
+\item if a \tcode{memory_order::seq_cst} fence $X$
+happens before $A$ and
+$B$ happens before
+a \tcode{memory_order::seq_cst} fence $Y$,
+then $X$ precedes $Y$ in $S$.
 \end{itemize}
 
 \pnum
 \begin{note}
-This definition ensures that \placeholder{S} is consistent with
-the modification order of any atomic object \placeholder{M}.
+This definition ensures that $S$ is consistent with
+the modification order of any atomic object $M$.
 It also ensures that
-a \tcode{memory_order::seq_cst} load \placeholder{A} of \placeholder{M}
-gets its value either from the last modification of \placeholder{M}
-that precedes \placeholder{A} in \placeholder{S} or
-from some non-\tcode{memory_order::seq_cst} modification of \placeholder{M}
-that does not happen before any modification of \placeholder{M}
-that precedes \placeholder{A} in \placeholder{S}.
+a \tcode{memory_order::seq_cst} load $A$ of $M$
+gets its value either from the last modification of $M$
+that precedes $A$ in $S$ or
+from some non-\tcode{memory_order::seq_cst} modification of $M$
+that does not happen before any modification of $M$
+that precedes $A$ in $S$.
 \end{note}
 
 \pnum
 \begin{note}
-We do not require that \placeholder{S} be consistent with
+We do not require that $S$ be consistent with
 ``happens before''\iref{intro.races}.
 This allows more efficient implementation
 of \tcode{memory_order::acquire} and \tcode{memory_order::release}
@@ -3522,27 +3522,27 @@
 fence}.
 
 \pnum
-A release fence \placeholder{A} synchronizes with an acquire fence \placeholder{B} if there exist
-atomic operations \placeholder{X} and \placeholder{Y}, both operating on some atomic object
-\placeholder{M}, such that \placeholder{A} is sequenced before \placeholder{X}, \placeholder{X} modifies
-\placeholder{M}, \placeholder{Y} is sequenced before \placeholder{B}, and \placeholder{Y} reads the value
-written by \placeholder{X} or a value written by any side effect in the hypothetical release
-sequence \placeholder{X} would head if it were a release operation.
+A release fence $A$ synchronizes with an acquire fence $B$ if there exist
+atomic operations $X$ and $Y$, both operating on some atomic object
+$M$, such that $A$ is sequenced before $X$, $X$ modifies
+$M$, $Y$ is sequenced before $B$, and $Y$ reads the value
+written by $X$ or a value written by any side effect in the hypothetical release
+sequence $X$ would head if it were a release operation.
 
 \pnum
-A release fence \placeholder{A} synchronizes with an atomic operation \placeholder{B} that
-performs an acquire operation on an atomic object \placeholder{M} if there exists an atomic
-operation \placeholder{X} such that \placeholder{A} is sequenced before \placeholder{X}, \placeholder{X}
-modifies \placeholder{M}, and \placeholder{B} reads the value written by \placeholder{X} or a value
-written by any side effect in the hypothetical release sequence \placeholder{X} would head if
+A release fence $A$ synchronizes with an atomic operation $B$ that
+performs an acquire operation on an atomic object $M$ if there exists an atomic
+operation $X$ such that $A$ is sequenced before $X$, $X$
+modifies $M$, and $B$ reads the value written by $X$ or a value
+written by any side effect in the hypothetical release sequence $X$ would head if
 it were a release operation.
 
 \pnum
-An atomic operation \placeholder{A} that is a release operation on an atomic object
-\placeholder{M} synchronizes with an acquire fence \placeholder{B} if there exists some atomic
-operation \placeholder{X} on \placeholder{M} such that \placeholder{X} is sequenced before \placeholder{B}
-and reads the value written by \placeholder{A} or a value written by any side effect in the
-release sequence headed by \placeholder{A}.
+An atomic operation $A$ that is a release operation on an atomic object
+$M$ synchronizes with an acquire fence $B$ if there exists some atomic
+operation $X$ on $M$ such that $X$ is sequenced before $B$
+and reads the value written by $A$ or a value written by any side effect in the
+release sequence headed by $A$.
 
 \indexlibraryglobal{atomic_thread_fence}%
 \begin{itemdecl}