PR c++/30849
	PR c++/30850
	PR c++/30851
	* parser.c (cp_parser_asm_definition): Detect and discard asm
	statements with invalid inputs or outputs.
        (cp_parser_asm_operand_list): Return error mark node if any
        of the operands are invalid. Adjust documentation.

	PR c++/30849
	* g++.dg/parse/asm1.C: New test.

	PR c++/30850
	* g++.dg/parse/asm2.C: Likewise.

	PR c++/30851
	* g++.dg/parse/asm3.C: Likewise.

From-SVN: r127167