Hi

This patch is only adding the missing LTGT to plug the ICE. This is a 
backport to r255625 of trunk.

Testing done: Checked for regressions on bootstrapped 
aarch64-none-linux-gnu and added a new compile time test case that gives 
out LTGT to make sure it doesn't ICE.

Is this ok for trunk?

Thanks
Sudi

ChangeLog Entries:

*** gcc/ChangeLog ***

2018-01-09  Sudakshina Das  <sudi.das@arm.com>
	    Bin Cheng  <bin.cheng@arm.com>

	Backport from mainline:
	2017-12-14  Sudakshina Das  <sudi.das@arm.com>
	    	    Bin Cheng  <bin.cheng@arm.com>

	PR target/81228
	* config/aarch64/aarch64.c (aarch64_select_cc_mode): Move LTGT to 
CCFPEmode.
	* config/aarch64/aarch64-simd.md (vec_cmp<mode><v_cmp_result>): Add
	LTGT.

*** gcc/testsuite/ChangeLog ***

2017-01-09  Sudakshina Das  <sudi.das@arm.com>

	Backport from mainline:
	2017-12-14  Sudakshina Das  <sudi.das@arm.com>

	PR target/81228
	* gcc.dg/pr81228.c: New.