[RFC ARM] Error if overriding --with-tune by --with-cpu

[James Greenhalgh]

Hi,

We error in the case where both --with-tune and --with-cpu are specified at
configure time. In this case, we cannot distinguish this situation from the
situation where --with-tune was specified at configure time and -mcpu was
passed on the command line, so we give -mcpu precedence.

This might be surprising if you expect the precedence rules we give
to the command line options, but we can't change this precedence without
breaking our definition of -mcpu.

We also promote the warning which used to be thrown in the case of
--with-arch and --with-cpu to an error.

I've marked this is an RFC as it isn't clear that configure should be
catching something like this. Other blatant errors in configuration
options like passing "--with-languages=c,c++" pass without event.

Tested with a few combinations of configure options with no issues and the
expected behaviour.

Any opinions, and if not, OK for trunk?

Thanks,
James

---
gcc/

2014-05-30  James Greenhalgh  <james.greenhalgh@arm.com>

	* config.gcc (supported_defaults): Error when passing either
	--with-tune or --with-arch in conjunction with --with-cpu for ARM.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-RFC-ARM-Error-if-overriding-with-tune-by-with-cpu.patch
Type: text/x-patch
Size: 590 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20140530/a8d09077/attachment.bin>