Fwd: [PATCH, doc/ARM] Remove false affirmation that Thumb cannot use an FPU

[Thomas Preudhomme]

Forwarding to gcc-patches which I forgot past patch #1

--- Begin Message --- GCC documentation for MULTILIB_EXCEPTIONS states that ARM processors cannot use hardware floating-point in Thumb execution state. This is incorrect since ARMv7E-M processors can do just that. This patch replace this example with the case of the meaningless -mfloat-abi=soft -mfpu=* combination of options. MULTILIB_EXCEPTIONS was indeed use to exclude such a case in config/arm/t-aprofile until patches preceding this one.

ChangeLog entry is as follows:


*** gcc/ChangeLog ***

2016-08-02  Thomas Preud'homme  <thomas.preudho...@arm.com>

        * doc/fragments.texi (MULTILIB_EXCEPTIONS): Replace example with
        preventing combination of -mfloat-abi=soft with any -mfpu option.


gccint.pdf builds fine with the patch and display is as expected.

Is this ok for trunk?

Best regards,

Thomas

diff --git a/gcc/doc/fragments.texi b/gcc/doc/fragments.texi
index b6d8541c8ca820fa732363a05221e2cd4d1251c2..a060635c9cee7374d9d187858ac87acdd08860f2 100644
--- a/gcc/doc/fragments.texi
+++ b/gcc/doc/fragments.texi
@@ -117,12 +117,15 @@ specified, there are combinations that should not be built.  In that
 case, set @code{MULTILIB_EXCEPTIONS} to be all of the switch exceptions
 in shell case syntax that should not be built.
 
-For example the ARM processor cannot execute both hardware floating
-point instructions and the reduced size THUMB instructions at the same
-time, so there is no need to build libraries with both of these
-options enabled.  Therefore @code{MULTILIB_EXCEPTIONS} is set to:
+For example on ARM targets @code{-mfloat-abi=soft} requests to use a
+softfloat implementation for floating-point operations.  Therefore, it
+does not make sense to find both @code{-mfloat-abi=soft} and an
+@code{mfpu} option on the command line so @code{MULTILIB_EXCEPTIONS}
+could contain the following exception (assuming that @code{-mfloat-abi}
+comes after in MULTILIB_OPTIONS and given that soft is the default
+value):
 @smallexample
-*mthumb/*mhard-float*
+*mfpu=*
 @end smallexample
 
 @findex MULTILIB_REQUIRED

--- End Message ---