From bb8b0096829209874018c0997f340a43ca8b0461 Mon Sep 17 00:00:00 2001
From: Richard Earnshaw <rearnsha@arm.com>
Date: Tue, 31 Jul 2018 17:35:41 +0000
Subject: [PATCH] Arm - add speculation_barrier pattern

This patch defines a speculation barrier for AArch32.

	* config/arm/unspecs.md (unspecv): Add VUNSPEC_SPECULATION_BARRIER.
	* config/arm/arm.md (speculation_barrier): New expand.
	(speculation_barrier_insn): New pattern.

From-SVN: r263169
---
 gcc/ChangeLog             |  6 ++++++
 gcc/config/arm/arm.md     | 21 +++++++++++++++++++++
 gcc/config/arm/unspecs.md |  1 +
 3 files changed, 28 insertions(+)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index de37f1f879c..63971fa1c9a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-07-31  Richard Earnshaw  <rearnsha@arm.com>
+
+	* config/arm/unspecs.md (unspecv): Add VUNSPEC_SPECULATION_BARRIER.
+	* config/arm/arm.md (speculation_barrier): New expand.
+	(speculation_barrier_insn): New pattern.
+
 2018-07-31  Richard Earnshaw  <rearnsha@arm.com>
 
 	* builtin-types.def (BT_FN_PTR_PTR_VAR): New function type.
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 361a02668b0..ca2a2f5469f 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -12012,6 +12012,27 @@
   [(set_attr "length" "4")
    (set_attr "type" "coproc")])
 
+(define_expand "speculation_barrier"
+  [(unspec_volatile [(const_int 0)] VUNSPEC_SPECULATION_BARRIER)]
+  "TARGET_EITHER"
+  "
+    /* Don't emit anything for Thumb1 and suppress the warning from the
+       generic expansion.  */
+    if (!TARGET_32BIT)
+       DONE;
+  "
+)
+
+;; Generate a hard speculation barrier when we have not enabled speculation
+;; tracking.
+(define_insn "*speculation_barrier_insn"
+  [(unspec_volatile [(const_int 0)] VUNSPEC_SPECULATION_BARRIER)]
+  "TARGET_32BIT"
+  "isb\;dsb\\tsy"
+  [(set_attr "type" "block")
+   (set_attr "length" "8")]
+)
+
 ;; Vector bits common to IWMMXT and Neon
 (include "vec-common.md")
 ;; Load the Intel Wireless Multimedia Extension patterns
diff --git a/gcc/config/arm/unspecs.md b/gcc/config/arm/unspecs.md
index b05f85e10e4..19416736ef9 100644
--- a/gcc/config/arm/unspecs.md
+++ b/gcc/config/arm/unspecs.md
@@ -168,6 +168,7 @@
   VUNSPEC_MCRR2		; Represent the coprocessor mcrr2 instruction.
   VUNSPEC_MRRC		; Represent the coprocessor mrrc instruction.
   VUNSPEC_MRRC2		; Represent the coprocessor mrrc2 instruction.
+  VUNSPEC_SPECULATION_BARRIER ; Represents an unconditional speculation barrier.
 ])
 
 ;; Enumerators for NEON unspecs.
-- 
2.30.2