[PATCH v5 1/1] RISC-V: Add support for XCVbi extension in CV32E40P

[PATCH v5 1/1] RISC-V: Add support for XCVbi extension in CV32E40P

Spec: github.com/openhwgroup/core-v-sw/blob/master/specifications/corev-builtin-spec.md

Contributors:
   Mary Bennett <mary.bennett@embecosm.com>
   Nandni Jamnadas <nandni.jamnadas@embecosm.com>
   Pietra Ferreira <pietra.ferreira@embecosm.com>
   Charlie Keaney
   Jessica Mills
   Craig Blackmore <craig.blackmore@embecosm.com>
   Simon Cook <simon.cook@embecosm.com>
   Jeremy Bennett <jeremy.bennett@embecosm.com>
   Helene Chelin <helene.chelin@embecosm.com>

gcc/ChangeLog:
	* common/config/riscv/riscv-common.cc: Create XCVbi extension
	support.
	* config/riscv/riscv.opt: Likewise.
	* config/riscv/corev.md: Implement cv_branch<mode> pattern
	for cv.beqimm and cv.bneimm.
	* config/riscv/riscv.md: Add CORE-V branch immediate to RISC-V
	branch instruction pattern.
	* config/riscv/constraints.md: Implement constraints
	cv_bi_s5 - signed 5-bit immediate.
	* config/riscv/predicates.md: Implement predicate
	const_int5s_operand - signed 5 bit immediate.
	* doc/sourcebuild.texi: Add XCVbi documentation.

gcc/testsuite/ChangeLog:
	* gcc.target/riscv/cv-bi-beqimm-compile-1.c: New test.
	* gcc.target/riscv/cv-bi-beqimm-compile-2.c: New test.
	* gcc.target/riscv/cv-bi-bneimm-compile-1.c: New test.
	* gcc.target/riscv/cv-bi-bneimm-compile-2.c: New test.
	* lib/target-supports.exp: Add proc for XCVbi.