[PATCH], Fix PR 80098, Add better checking for disabling features

[Michael Meissner <meissner at linux dot vnet dot ibm dot com>]

PR 80098 is an interaction between -mmodulo (ISA 3.0/power9 GPR modulo
instructions) and -mno-vsx where the -mmodulo option enables some of the ISA
3.0 vector features, even though -mno-vsx was specified.

To do this, I added a table for disabling other vector options when the major
vector options (-mvsx, -mpower8-vector, and -mpower9-vector) are disabled.

We could extend this if desired for other options (for example, -mno-popcntd
could disable -mmodulo and perhaps the vector options).

I built and tested the compiler on a little endian power8 Linux system and
there were no regressions.  Is it ok for the trunk?

[gcc]
2017-04-11  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/80098
	* config/rs6000/rs6000-cpus.def (OTHER_P9_VECTOR_MASKS): Define
	masks of options that should be turned off if the VSX vector
	options are turned off.
	(OTHER_P8_VECTOR_MASKS): Likewise.
	(OTHER_VSX_VECTOR_MASKS): Likewise.
	* config/rs6000/rs6000.c (rs6000_option_override_internal): Call
	rs6000_disable_incompatible_switches to validate no type switches
	like -mvsx.
	(rs6000_incompatible_switch): New function to disallow turning on
	other vector options if -mno-vsx, -mno-power8-vector, or
	-mno-power9-vector are specified.

[gcc/testsuite]
2017-04-11  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/80098
	* gcc.target/powerpc/pr80098-1.c: New test.
	* gcc.target/powerpc/pr80098-2.c: Likewise.
	* gcc.target/powerpc/pr80098-3.c: Likewise.
	* gcc.target/powerpc/pr80098-4.c: Likewise.

-- 
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meissner@linux.vnet.ibm.com, phone: +1 (978) 899-4797

Attachment: pr80098.patch02b
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