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| author | Michael Meissner <meissner@linux.vnet.ibm.com> | 2018-02-07 23:58:28 +0000 |
|---|---|---|
| committer | Michael Meissner <meissner@gcc.gnu.org> | 2018-02-07 23:58:28 +0000 |
| commit | d2591b682773cbe3a4451dcf2a54f777a47588c7 (patch) | |
| tree | 6df7b71c33d7cf3988b16623db8c4f77a970490f | |
| parent | 11e887c45a6a1c708016a08c8aeeae03b30a007b (diff) | |
| download | gcc-d2591b682773cbe3a4451dcf2a54f777a47588c7.zip gcc-d2591b682773cbe3a4451dcf2a54f777a47588c7.tar.gz gcc-d2591b682773cbe3a4451dcf2a54f777a47588c7.tar.bz2 | |
install.texi (Configuration): Document the --with-long-double-format={ibm,ieee} PowerPC configuration options.
2018-02-07 Michael Meissner <meissner@linux.vnet.ibm.com>
* doc/install.texi (Configuration): Document the
--with-long-double-format={ibm,ieee} PowerPC configuration
options.
From-SVN: r257473
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/doc/install.texi | 29 |
2 files changed, 33 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index a4f295ea..e51ba4f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -6,6 +6,10 @@ 2018-02-07 Michael Meissner <meissner@linux.vnet.ibm.com> + * doc/install.texi (Configuration): Document the + --with-long-double-format={ibm,ieee} PowerPC configuration + options. + PR target/84154 * config/rs6000/rs6000.md (fix_trunc<SFDF:mode><QHI:mode>2): Convert from define_expand to be define_insn_and_split. Rework diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi index 9435565..64ad244 100644 --- a/gcc/doc/install.texi +++ b/gcc/doc/install.texi @@ -1877,6 +1877,35 @@ When neither of these configure options are used, the default will be 128-bit @code{long double} when built against GNU C Library 2.4 and later, 64-bit @code{long double} otherwise. +@item --with-long-double-format=ibm +@itemx --with-long-double-format=ieee +Specify whether @code{long double} uses the IBM extended double format +or the IEEE 128-bit floating point format on PowerPC Linux systems. +This configuration switch will only work on little endian PowerPC +Linux systems and on big endian 64-bit systems where the default cpu +is at least power7 (i.e. @option{--with-cpu=power7}, +@option{--with-cpu=power8}, or @option{--with-cpu=power9} is used). + +If you use the @option{--with-long-double-64} configuration option, +the @option{--with-long-double-format=ibm} and +@option{--with-long-double-format=ieee} options are ignored. + +The default @code{long double} format is to use IBM extended double. +Until all of the libraries are converted to use IEEE 128-bit floating +point, it is not recommended to use +@option{--with-long-double-format=ieee}. + +On little endian PowerPC Linux systems, if you explicitly set the +@code{long double} type, it will build multilibs to allow you to +select either @code{long double} format, unless you disable multilibs +with the @code{--disable-multilib} option. At present, +@code{long double} multilibs are not built on big endian PowerPC Linux +systems. If you are building multilibs, you will need to configure +the compiler using the @option{--with-system-zlib} option. + +If you do not set the @code{long double} type explicitly, no multilibs +will be generated. + @item --enable-fdpic On SH Linux systems, generate ELF FDPIC code. |