diff mbox series

[v3,03/23] aarch64: Add support for chkfeat insn

Message ID 20241108144816.2681175-4-yury.khrustalev@arm.com
State New
Headers show
Series aarch64: Add support for Guarded Control Stack extension | expand

Commit Message

Yury Khrustalev Nov. 8, 2024, 2:47 p.m. UTC 
From: Szabolcs Nagy <szabolcs.nagy@arm.com>

This is a hint space instruction to check for enabled HW features and
update the x16 register accordingly.

Use unspec_volatile to prevent reordering it around calls since calls
can enable or disable HW features.

gcc/ChangeLog:

	* config/aarch64/aarch64.md (aarch64_chkfeat): New.
---
 gcc/config/aarch64/aarch64.md | 9 +++++++++
 1 file changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 8d10197c9e8..0c5694f3e5e 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -381,6 +381,7 @@  (define_c_enum "unspecv" [
     UNSPECV_BTI_C		; Represent BTI c.
     UNSPECV_BTI_J		; Represent BTI j.
     UNSPECV_BTI_JC		; Represent BTI jc.
+    UNSPECV_CHKFEAT		; Represent CHKFEAT X16.
     UNSPECV_TSTART		; Represent transaction start.
     UNSPECV_TCOMMIT		; Represent transaction commit.
     UNSPECV_TCANCEL		; Represent transaction cancel.
@@ -8309,6 +8310,14 @@  (define_insn "aarch64_restore_nzcv"
   "msr\tnzcv, %0"
 )
 
+;; CHKFEAT instruction
+(define_insn "aarch64_chkfeat"
+  [(set (reg:DI R16_REGNUM)
+        (unspec_volatile:DI [(reg:DI R16_REGNUM)] UNSPECV_CHKFEAT))]
+  ""
+  "hint\\t40 // chkfeat x16"
+)
+
 ;; AdvSIMD Stuff
 (include "aarch64-simd.md")