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[PATCH 3/7] AArch64 - add speculation barrier
- From: Richard Earnshaw <Richard dot Earnshaw at arm dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Richard Earnshaw <Richard dot Earnshaw at arm dot com>, richard dot earnshaw at arm dot com
- Date: Mon, 9 Jul 2018 17:38:15 +0100
- Subject: [PATCH 3/7] AArch64 - add speculation barrier
- References: <1531154299-28349-1-git-send-email-Richard.Earnshaw@arm.com>
Similar to Arm, this adds an unconditional speculation barrier for AArch64.
* config/aarch64.md (unspecv): Add UNSPECV_SPECULAION_BARRIER.
(speculation_barrier): New insn.
---
gcc/config/aarch64/aarch64.md | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index a014a01..c135ada 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -205,6 +205,7 @@ (define_c_enum "unspecv" [
UNSPECV_SET_FPSR ; Represent assign of FPSR content.
UNSPECV_BLOCKAGE ; Represent a blockage
UNSPECV_PROBE_STACK_RANGE ; Represent stack range probing.
+ UNSPECV_SPECULATION_BARRIER ; Represent speculation barrier.
]
)
@@ -6093,6 +6094,15 @@ (define_expand "set_clobber_cc"
(match_operand 1))
(clobber (reg:CC CC_REGNUM))])])
+;; Hard speculation barrier.
+(define_insn "speculation_barrier"
+ [(unspec_volatile [(const_int 0)] UNSPECV_SPECULATION_BARRIER)]
+ ""
+ "isb\;dsb\\tsy"
+ [(set_attr "length" "8")
+ (set_attr "type" "block")]
+)
+
;; AdvSIMD Stuff
(include "aarch64-simd.md")