[gcc/devel/c++-coroutines] [AArch64] Fix shrinkwrapping interactions with atomics (PR92692)

[Iain D Sandoe]

https://gcc.gnu.org/g:e5e07b68187b9aa334519746c45b8cffc5eb7e5c

commit e5e07b68187b9aa334519746c45b8cffc5eb7e5c
Author: Wilco Dijkstra <wdijkstr@arm.com>
Date:   Fri Jan 17 13:17:21 2020 +0000

    [AArch64] Fix shrinkwrapping interactions with atomics (PR92692)
    
    The separate shrinkwrapping pass may insert stores in the middle
    of atomics loops which can cause issues on some implementations.
    Avoid this by delaying splitting atomics patterns until after
    prolog/epilog generation.
    
    gcc/
    	PR target/92692
    	* config/aarch64/aarch64.c (aarch64_split_compare_and_swap)
    	Add assert to ensure prolog has been emitted.
    	(aarch64_split_atomic_op): Likewise.
    	* config/aarch64/atomics.md (aarch64_compare_and_swap<mode>)
    	Use epilogue_completed rather than reload_completed.
    	(aarch64_atomic_exchange<mode>): Likewise.
    	(aarch64_atomic_<atomic_optab><mode>): Likewise.
    	(atomic_nand<mode>): Likewise.
    	(aarch64_atomic_fetch_<atomic_optab><mode>): Likewise.
    	(atomic_fetch_nand<mode>): Likewise.
    	(aarch64_atomic_<atomic_optab>_fetch<mode>): Likewise.
    	(atomic_nand_fetch<mode>): Likewise.

Diff:
---
 gcc/ChangeLog                 | 16 ++++++++++++++++
 gcc/config/aarch64/aarch64.c  |  6 ++++++
 gcc/config/aarch64/atomics.md | 20 ++++++++++----------
 3 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 49ca5f9..06bcb81 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,19 @@
+2020-01-17  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	PR target/92692
+	* config/aarch64/aarch64.c (aarch64_split_compare_and_swap)
+	Add assert to ensure prolog has been emitted.
+	(aarch64_split_atomic_op): Likewise.
+	* config/aarch64/atomics.md (aarch64_compare_and_swap<mode>)
+	Use epilogue_completed rather than reload_completed.
+	(aarch64_atomic_exchange<mode>): Likewise.
+	(aarch64_atomic_<atomic_optab><mode>): Likewise.
+	(atomic_nand<mode>): Likewise.
+	(aarch64_atomic_fetch_<atomic_optab><mode>): Likewise.
+	(atomic_fetch_nand<mode>): Likewise.
+	(aarch64_atomic_<atomic_optab>_fetch<mode>): Likewise.
+	(atomic_nand_fetch<mode>): Likewise.
+
 2020-01-17  Richard Sandiford  <richard.sandiford@arm.com>
 
 	PR target/93133
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 3660ce7..ea9d6a1 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -18375,6 +18375,9 @@ aarch64_emit_post_barrier (enum memmodel model)
 void
 aarch64_split_compare_and_swap (rtx operands[])
 {
+  /* Split after prolog/epilog to avoid interactions with shrinkwrapping.  */
+  gcc_assert (epilogue_completed);
+
   rtx rval, mem, oldval, newval, scratch, x, model_rtx;
   machine_mode mode;
   bool is_weak;
@@ -18469,6 +18472,9 @@ void
 aarch64_split_atomic_op (enum rtx_code code, rtx old_out, rtx new_out, rtx mem,
 			 rtx value, rtx model_rtx, rtx cond)
 {
+  /* Split after prolog/epilog to avoid interactions with shrinkwrapping.  */
+  gcc_assert (epilogue_completed);
+
   machine_mode mode = GET_MODE (mem);
   machine_mode wmode = (mode == DImode ? DImode : SImode);
   const enum memmodel model = memmodel_from_int (INTVAL (model_rtx));
diff --git a/gcc/config/aarch64/atomics.md b/gcc/config/aarch64/atomics.md
index c2bcabd..9969477 100644
--- a/gcc/config/aarch64/atomics.md
+++ b/gcc/config/aarch64/atomics.md
@@ -56,7 +56,7 @@
    (clobber (match_scratch:SI 7 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
     aarch64_split_compare_and_swap (operands);
@@ -80,7 +80,7 @@
    (clobber (match_scratch:SI 7 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
     aarch64_split_compare_and_swap (operands);
@@ -104,7 +104,7 @@
    (clobber (match_scratch:SI 7 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
     aarch64_split_compare_and_swap (operands);
@@ -223,7 +223,7 @@
    (clobber (match_scratch:SI 4 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
     aarch64_split_atomic_op (SET, operands[0], NULL, operands[1],
@@ -344,7 +344,7 @@
   (clobber (match_scratch:SI 4 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
     aarch64_split_atomic_op (<CODE>, NULL, operands[3], operands[0],
@@ -400,7 +400,7 @@
    (clobber (match_scratch:SI 4 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
      aarch64_split_atomic_op (NOT, NULL, operands[3], operands[0],
@@ -504,7 +504,7 @@
    (clobber (match_scratch:SI 5 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
     aarch64_split_atomic_op (<CODE>, operands[0], operands[4], operands[1],
@@ -551,7 +551,7 @@
    (clobber (match_scratch:SI 5 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
     aarch64_split_atomic_op (NOT, operands[0], operands[4], operands[1],
@@ -604,7 +604,7 @@
    (clobber (match_scratch:SI 4 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
     aarch64_split_atomic_op (<CODE>, NULL, operands[0], operands[1],
@@ -628,7 +628,7 @@
    (clobber (match_scratch:SI 4 "=&r"))]
   ""
   "#"
-  "&& reload_completed"
+  "&& epilogue_completed"
   [(const_int 0)]
   {
     aarch64_split_atomic_op (NOT, NULL, operands[0], operands[1],