re PR fortran/52884 (double precision constants promoted to 16 byte by -fdefault-real-8)

2019-01-30  Dominique d'Humieres  <dominiq@gcc.gnu.org>

	PR fortran/52884
	* invoke.texi: Document the promotion of double precision
	constants.

From-SVN: r268396

2 files changed, 36 insertions, 21 deletions

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 5b30ac6..ac9169a 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,9 @@
+2019-01-30  Dominique d'Humieres  <dominiq@gcc.gnu.org>
+
+	PR fortran/52884
+	* invoke.texi: Document the promotion of double precision
+	constants.
+
 2019-01-29  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	PR fortran/57048
diff --git a/gcc/fortran/invoke.texi b/gcc/fortran/invoke.texi
index dc7c037..deaf8eb 100644
--- a/gcc/fortran/invoke.texi
+++ b/gcc/fortran/invoke.texi
@@ -416,36 +416,45 @@ kind declaration.
 
 @item -fdefault-real-8
 @opindex @code{fdefault-real-8}
-Set the default real type to an 8 byte wide type. This option also affects
-the kind of non-double real constants like @code{1.0}, and does promote
-the default width of @code{DOUBLE PRECISION} to 16 bytes if possible, unless
-@code{-fdefault-double-8} is given, too. Unlike @option{-freal-4-real-8},
-it does not promote variables with explicit kind declaration.
+Set the default real type to an 8 byte wide type.  This option also affects
+the kind of non-double real constants like @code{1.0}.  This option promotes
+the default width of @code{DOUBLE PRECISION} and double real constants
+like @code{1.d0} to 16 bytes if possible.  If @code{-fdefault-double-8}
+is given along with @code{fdefault-real-8}, @code{DOUBLE PRECISION}
+and double real constants are not promoted.  Unlike @option{-freal-4-real-8},
+@code{fdefault-real-8} does not promote variables with explicit kind
+declarations.
 
 @item -fdefault-real-10
 @opindex @code{fdefault-real-10}
-Set the default real type to a 10 byte wide type. This option also affects
-the kind of non-double real constants like @code{1.0}, and does promote
-the default width of @code{DOUBLE PRECISION} to 16 bytes if possible, unless
-@code{-fdefault-double-8} is given. Unlike @option{-freal-4-real-10},
-it does not promote variables with explicit kind declaration.
+Set the default real type to an 10 byte wide type.  This option also affects
+the kind of non-double real constants like @code{1.0}.  This option promotes
+the default width of @code{DOUBLE PRECISION} and double real constants
+like @code{1.d0} to 16 bytes if possible.  If @code{-fdefault-double-8}
+is given along with @code{fdefault-real-10}, @code{DOUBLE PRECISION}
+and double real constants are not promoted.  Unlike @option{-freal-4-real-10},
+@code{fdefault-real-10} does not promote variables with explicit kind
+declarations.
 
 @item -fdefault-real-16
 @opindex @code{fdefault-real-16}
-Set the default real type to a 16 byte wide type. This option also affects
-the kind of non-double real constants like @code{1.0}, and does promote
-the default width of @code{DOUBLE PRECISION} to 16 bytes if possible, unless
-@code{-fdefault-double-8} is given. Unlike @option{-freal-4-real-16},
-it does not promote variables with explicit kind declaration.
+Set the default real type to an 16 byte wide type.  This option also affects
+the kind of non-double real constants like @code{1.0}.  This option promotes
+the default width of @code{DOUBLE PRECISION} and double real constants
+like @code{1.d0} to 16 bytes if possible.  If @code{-fdefault-double-8}
+is given along with @code{fdefault-real-16}, @code{DOUBLE PRECISION}
+and double real constants are not promoted.  Unlike @option{-freal-4-real-16},
+@code{fdefault-real-16} does not promote variables with explicit kind
+declarations.
 
 @item -fdefault-double-8
 @opindex @code{fdefault-double-8}
-Set the @code{DOUBLE PRECISION} type to an 8 byte wide type.  Do nothing if this
-is already the default.  If @option{-fdefault-real-8} is given,
-@code{DOUBLE PRECISION} would instead be promoted to 16 bytes if possible, and
-@option{-fdefault-double-8} can be used to prevent this.  The kind of real
-constants like @code{1.d0} will not be changed by @option{-fdefault-real-8}
-though, so also @option{-fdefault-double-8} does not affect it.
+Set the @code{DOUBLE PRECISION} type and double real constants
+like @code{1.d0} to an 8 byte wide type.  Do nothing if this
+is already the default.  This option prevents @option{-fdefault-real-8},
+@option{-fdefault-real-10}, and @option{-fdefault-real-16},
+from promoting @code{DOUBLE PRECISION} and double real constants like
+@code{1.d0} to 16 bytes.
 
 @item -finteger-4-integer-8
 @opindex @code{finteger-4-integer-8}