[ARM] Update sourcebuild.texi with testsuite/effective-target hooks

	* doc/sourcebuild.texi (arm_neon_fp16): Correct cross-reference.
	(arm_neon_fp16_ok): Document adding of -mfp16-format=ieee flag.
	(arm_neon_fp16_hw): New.

From-SVN: r227556

gcc/ChangeLog

 2015-09-08  Alan Lawrence  <alan.lawrence@arm.com>
 
+	* doc/sourcebuild.texi (arm_neon_fp16): Correct cross-reference.
+	(arm_neon_fp16_ok): Document adding of -mfp16-format=ieee flag.
+	(arm_neon_fp16_hw): New.
+
+2015-09-08  Alan Lawrence  <alan.lawrence@arm.com>
+
 	* fold-const.c (native_interpret_real): Fix HFmode for bigendian where
 	UNITS_PER_WORD >= 4.
 

gcc/doc/sourcebuild.texi

@@ -1549,7 +1549,12 @@ options.  Some multilibs may be incompatible with these options.
 @item arm_neon_fp16_ok
 @anchor{arm_neon_fp16_ok}
 ARM Target supports @code{-mfpu=neon-fp16 -mfloat-abi=softfp} or compatible
-options.  Some multilibs may be incompatible with these options.
+options, including @code{-mfp16-format=ieee} if necessary to obtain the
+@code{__fp16} type.  Some multilibs may be incompatible with these options.
+
+@item arm_neon_fp16_hw
+Test system supports executing Neon half-precision float instructions.
+(Implies previous.)
 
 @item arm_thumb1_ok
 ARM target generates Thumb-1 code for @code{-mthumb}.
@@ -2035,7 +2040,7 @@ keyword}.
 @item arm_neon_fp16
 NEON and half-precision floating point support.  Only ARM targets
 support this feature, and only then in certain modes; see
-the @ref{arm_neon_ok,,arm_neon_fp16_ok effective target keyword}.
+the @ref{arm_neon_fp16_ok,,arm_neon_fp16_ok effective target keyword}.
 
 @item arm_vfp3
 arm vfp3 floating point support; see