[gcc(refs/vendors/redhat/heads/gcc-8-branch)] aarch64: Fix up aarch64_compare_and_swaphi pattern [PR94368]

[Jakub Jelinek]

https://gcc.gnu.org/g:4c8634323d67db0c7cda0d06ee3368e2285a9de9

commit 4c8634323d67db0c7cda0d06ee3368e2285a9de9
Author: Andre Vieira <andre.simoesdiasvieira@arm.com>
Date:   Thu Apr 16 10:16:17 2020 +0100

    aarch64: Fix up aarch64_compare_and_swaphi pattern [PR94368]
    
    2020-04-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>
    
            Backport from mainline
            2020-03-31  Jakub Jelinek  <jakub@redhat.com>
    
            PR target/94368
            * config/aarch64/constraints.md (Uph): New constraint.
            * config/aarch64/atomics.md (cas_short_expected_imm): New mode attr.
            (aarch64_compare_and_swap<mode>): Use it instead of n in operand 2's
            constraint.
    
            * gcc.dg/pr94368.c: New test.

Diff:
---
 gcc/ChangeLog                     | 11 +++++++++++
 gcc/config/aarch64/atomics.md     |  5 ++++-
 gcc/config/aarch64/constraints.md |  7 +++++++
 gcc/testsuite/ChangeLog           |  7 +++++++
 gcc/testsuite/gcc.dg/pr94368.c    | 25 +++++++++++++++++++++++++
 5 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b2673a3bdf8..7726debb519 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2020-04-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>
+
+	Backport from mainline
+	2020-03-31  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/94368
+	* config/aarch64/constraints.md (Uph): New constraint.
+	* config/aarch64/atomics.md (cas_short_expected_imm): New mode attr.
+	(aarch64_compare_and_swap<mode>): Use it instead of n in operand 2's
+	constraint.
+
 2020-04-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>
 
 	Backport from mainline
diff --git a/gcc/config/aarch64/atomics.md b/gcc/config/aarch64/atomics.md
index 0ee8d2efac0..1005462ae23 100644
--- a/gcc/config/aarch64/atomics.md
+++ b/gcc/config/aarch64/atomics.md
@@ -38,6 +38,8 @@
 
 (define_mode_attr cas_short_expected_pred
   [(QI "aarch64_reg_or_imm") (HI "aarch64_plushi_operand")])
+(define_mode_attr cas_short_expected_imm
+  [(QI "n") (HI "Uph")])
 
 (define_insn_and_split "aarch64_compare_and_swap<mode>"
   [(set (reg:CC CC_REGNUM)					;; bool out
@@ -47,7 +49,8 @@
       (match_operand:SHORT 1 "aarch64_sync_memory_operand" "+Q"))) ;; memory
    (set (match_dup 1)
     (unspec_volatile:SHORT
-      [(match_operand:SHORT 2 "<cas_short_expected_pred>" "rn")	;; expected
+      [(match_operand:SHORT 2 "<cas_short_expected_pred>"
+			      "r<cas_short_expected_imm>")	;; expected
        (match_operand:SHORT 3 "aarch64_reg_or_zero" "rZ")	;; desired
        (match_operand:SI 4 "const_int_operand")			;; is_weak
        (match_operand:SI 5 "const_int_operand")			;; mod_s
diff --git a/gcc/config/aarch64/constraints.md b/gcc/config/aarch64/constraints.md
index 32a0fa60a19..03626d2faf8 100644
--- a/gcc/config/aarch64/constraints.md
+++ b/gcc/config/aarch64/constraints.md
@@ -213,6 +213,13 @@
   (and (match_code "const_int")
        (match_test "(unsigned) exact_log2 (ival) <= 4")))
 
+(define_constraint "Uph"
+  "@internal
+  A constraint that matches HImode integers zero extendable to
+  SImode plus_operand."
+  (and (match_code "const_int")
+       (match_test "aarch64_plushi_immediate (op, VOIDmode)")))
+
 (define_memory_constraint "Q"
  "A memory address which uses a single base register with no offset."
  (and (match_code "mem")
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f33a7e998f6..6d1bd3d504a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2020-04-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>
+
+	Backport from mainline
+	2020-03-31  Jakub Jelinek  <jakub@redhat.com>
+
+	* gcc.dg/pr94368.c: New test.
+
 2020-04-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>
 
 	Backport from mainline
diff --git a/gcc/testsuite/gcc.dg/pr94368.c b/gcc/testsuite/gcc.dg/pr94368.c
new file mode 100644
index 00000000000..1267b822098
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94368.c
@@ -0,0 +1,25 @@
+/* PR target/94368 */
+/* { dg-do compile { target fpic } } */
+/* { dg-options "-fpic -O1 -fcommon" } */
+
+int b, c, d, e, f, h;
+short g;
+int foo (int) __attribute__ ((__const__));
+
+void
+bar (void)
+{
+  while (1)
+    {
+      while (1)
+	{
+	  __atomic_load_n (&e, 0);
+	  if (foo (2))
+	    __sync_val_compare_and_swap (&c, 0, f);
+	  b = 1;
+	  if (h == e)
+	    break;
+	}
+      __sync_val_compare_and_swap (&g, -1, f);
+    }
+}