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.

(backported be626997e0edc646c17e9e1eadabf97152e82eeb)

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@263169 138bc75d-0d04-0410-961f-82ee72b054a4

Change-Id: I5f587e22dd1a92440a6a208e2baca189427557da

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9c1bbc5..ab2e761 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 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.
        (BT_FN_I1_I1_VAR, BT_FN_I2_I2_VAR, BT_FN_I4_I4_VAR): Likewise.
        (BT_FN_I8_I8_VAR, BT_FN_I16_I16_VAR): Likewise.

diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 5cc6997..ffdd6c2 100644 (file)
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -11921,6 +11921,27 @@
   DONE;
 })
 
+(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 1aa39e8..db96cf1 100644 (file)
--- a/gcc/config/arm/unspecs.md
+++ b/gcc/config/arm/unspecs.md
@@ -150,6 +150,7 @@
   VUNSPEC_GET_FPSCR    ; Represent fetch of FPSCR content.
   VUNSPEC_SET_FPSCR    ; Represent assign of FPSCR content.
   VUNSPEC_PROBE_STACK_RANGE ; Represent stack range probing.
+  VUNSPEC_SPECULATION_BARRIER ; Represents an unconditional speculation barrier.
 ])
 
 ;; Enumerators for NEON unspecs.