Disallow 'B' constraints on amdgcn addc/subb

Disallow 'B' constraints on amdgcn addc/subb

2020-01-07  Andrew Stubbs  <ams@codesourcery.com>

	gcc/
	* config/gcn/constraints.md (DA): Update description and match.
	(DB): Likewise.
	(Db): New constraint.
	* config/gcn/gcn-protos.h (gcn_inline_constant64_p): Add second
	parameter.
	* config/gcn/gcn.c (gcn_inline_constant64_p): Add 'mixed' parameter.
	Implement 'Db' mixed immediate type.
	* config/gcn/gcn-valu.md (addcv64si3<exec_vcc>): Rework constraints.
	(addcv64si3_dup<exec_vcc>): Delete.
	(subcv64si3<exec_vcc>): Rework constraints.
	(addv64di3): Rework constraints.
	(addv64di3_exec): Rework constraints.
	(subv64di3): Rework constraints.
	(addv64di3_dup): Delete.
	(addv64di3_dup_exec): Delete.
	(addv64di3_zext): Rework constraints.
	(addv64di3_zext_exec): Rework constraints.
	(addv64di3_zext_dup): Rework constraints.
	(addv64di3_zext_dup_exec): Rework constraints.
	(addv64di3_zext_dup2): Rework constraints.
	(addv64di3_zext_dup2_exec): Rework constraints.
	(addv64di3_sext_dup2): Rework constraints.
	(addv64di3_sext_dup2_exec): Rework constraints.

From-SVN: r279959