[PATCH 1/4][ARM][PR target/65697][5.1] Backport stronger barriers for __sync fetch-op builtins.

[Matthew Wahab]

The __sync builtins are implemented using barriers that are too weak for ARMv8
targets, this has been fixed on trunk for the ARM back-end. Since GCC-5.1 is
also generating the incorrect code, it should also be fixed.

This patch backports the changes made to strengthen the barriers emitted for
the __sync fetch-and-op/op-and-fetch builtins.

The trunk patch submission is at
https://gcc.gnu.org/ml/gcc-patches/2015-06/msg01410.html
The commit is at https://gcc.gnu.org/ml/gcc-cvs/2015-06/msg01235.html

Tested the series for arm-none-linux-gnueabihf with check-gcc

Ok for the branch?
Matthew

2015-07-02  Matthew Wahab  <matthew.wahab@arm.com>

	Backport from trunk:
	2015-06-29  Matthew Wahab  <matthew.wahab@arm.com>

	PR target/65697
	* config/armc/arm.c (arm_split_atomic_op): For ARMv8, replace an
	initial acquire barrier with final barrier.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-2015-07-01-Matthew-Wahab-matthew.wahab-arm.com.patch
Type: text/x-patch
Size: 2083 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20150702/e9572828/attachment.bin>