Re: [PATCH, i386]: Extend TARGET_READ_MODIFY{,_WRITE} peepholes to all integer modes

[Uros Bizjak <ubizjak@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 324 bytes --]

On Fri, Apr 29, 2016 at 9:58 AM, Eric Botcazou <ebotcazou@adacore.com> wrote:
>> We can put it back, but prehaps implemented as unspec, so it won't
>> interfere with peepholes?
>
> No strong opinion, as long as the final assembly is the same as before.

I'm testing the attached patch. Does it fix your ada failures?

Uros.

[-- Attachment #2: r.diff.txt --]
[-- Type: text/plain, Size: 1038 bytes --]

Index: i386.md
===================================================================
--- i386.md	(revision 235620)
+++ i386.md	(working copy)
@@ -88,6 +88,7 @@
   UNSPEC_SET_GOT_OFFSET
   UNSPEC_MEMORY_BLOCKAGE
   UNSPEC_STACK_CHECK
+  UNSPEC_PROBE_STACK
 
   ;; TLS support
   UNSPEC_TP
@@ -17552,6 +17553,23 @@
   DONE;
 })
 
+(define_expand "probe_stack"
+  [(parallel
+     [(set (match_operand 0 "memory_operand")
+	   (unspec [(const_int 0)] UNSPEC_PROBE_STACK))
+      (clobber (reg:CC FLAGS_REG))])])
+
+;; Use OR for stack probes, this is shorter.
+(define_insn "*probe_stack_<mode>"
+  [(set (match_operand:W 0 "memory_operand" "=m")
+	(unspec:W [(const_int 0)] UNSPEC_PROBE_STACK))
+   (clobber (reg:CC FLAGS_REG))]
+  ""
+  "or{<imodesuffix>}\t{$0, %0|%0, 0}"
+  [(set_attr "type" "alu1")
+   (set_attr "mode" "<MODE>")
+   (set_attr "length_immediate" "1")])
+  
 (define_insn "adjust_stack_and_probe<mode>"
   [(set (match_operand:P 0 "register_operand" "=r")
 	(unspec_volatile:P [(match_operand:P 1 "register_operand" "0")]