[GCC, AArch64] Enable Transactional Memory Extension

[GCC, AArch64] Enable Transactional Memory Extension

This patch enables the new Transactional Memory Extension announced recently
as part of Arm's new architecture technologies.
We introduce a new optional extension "tme" to enable this. The following
instructions are part of the extension:
   * tstart <Xt>
   * ttest <Xt>
   * tcommit
   * tcancel #<imm>
We have also added ACLE intrinsics for the instructions.

*** gcc/ChangeLog ***

2019-07-31  Sudakshina Das  <sudi.das@arm.com>

	* config/aarch64/aarch64-builtins.c (enum aarch64_builtins): Add
	AARCH64_TME_BUILTIN_TSTART, AARCH64_TME_BUILTIN_TCOMMIT,
	AARCH64_TME_BUILTIN_TTEST and AARCH64_TME_BUILTIN_TCANCEL.
	(aarch64_init_tme_builtins): New.
	(aarch64_init_builtins): Call aarch64_init_tme_builtins.
	(aarch64_expand_builtin_tme): New.
	(aarch64_expand_builtin): Handle TME builtins.
	* config/aarch64/aarch64-c.c (aarch64_update_cpp_builtins): Define
	__ARM_FEATURE_TME when enabled.
	* config/aarch64/aarch64-option-extensions.def: Add "tme".
	* config/aarch64/aarch64.h (AARCH64_FL_TME, AARCH64_ISA_TME): New.
	(TARGET_TME): New.
	* config/aarch64/aarch64.md (define_c_enum "unspec"): Add UNSPEC_TTEST.
	(define_c_enum "unspecv"): Add UNSPECV_TSTART, UNSPECV_TCOMMIT and
	UNSPECV_TCANCEL.
	(tstart, ttest, tcommit, tcancel): New instructions.
	* config/aarch64/arm_acle.h (__tstart, __tcommit): New.
	(__tcancel, __ttest): New.
	(_TMFAILURE_REASON, _TMFAILURE_RTRY, _TMFAILURE_CNCL): New macro.
	(_TMFAILURE_MEM, _TMFAILURE_IMP, _TMFAILURE_ERR): Likewise.
	(_TMFAILURE_SIZE, _TMFAILURE_NEST, _TMFAILURE_DBG): Likewise.
	(_TMFAILURE_INT, _TMFAILURE_TRIVIAL): Likewise.
	* config/arm/types.md: Add new tme type attr.
	* doc/invoke.texi: Document "tme".

*** gcc/testsuite/ChangeLog ***

2019-07-31  Sudakshina Das  <sudi.das@arm.com>

	* gcc.target/aarch64/acle/tme.c: New test.
	* gcc.target/aarch64/pragma_cpp_predefs_2.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@273926 138bc75d-0d04-0410-961f-82ee72b054a4