[gcc(refs/vendors/ARM/heads/arm-perf-staging)] rs6000: Small improvement to the C++17 ABI fix [PR94707]

[Tamar Christina]

https://gcc.gnu.org/g:239cfd92e9ce5014a7616f692e0c6d4f337227b8

commit 239cfd92e9ce5014a7616f692e0c6d4f337227b8
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Apr 23 14:43:18 2020 +0200

    rs6000: Small improvement to the C++17 ABI fix [PR94707]
    
    Anyway, based on IRC discussion with Richard Sandiford on IRC, we should
    probably test type uids instead of type pointers because type uids aren't
    reused, but type pointers in a very bad luck case could be, and having the
    static var at filescope and GTY((deletable)) is an overkill (and with costs
    during GC time).
    
    2020-04-23  Jakub Jelinek  <jakub@redhat.com>
    
            PR target/94707
            * config/rs6000/rs6000-call.c (rs6000_discover_homogeneous_aggregate):
            Use TYPE_UID (TYPE_MAIN_VARIANT (type)) instead of type to check
            if the same type has been diagnosed most recently already.

Diff:
---
 gcc/ChangeLog                   | 7 +++++++
 gcc/config/rs6000/rs6000-call.c | 7 ++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5f299e463db..69f07c4f663 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2020-04-23  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/94707
+	* config/rs6000/rs6000-call.c (rs6000_discover_homogeneous_aggregate):
+	Use TYPE_UID (TYPE_MAIN_VARIANT (type)) instead of type to check
+	if the same type has been diagnosed most recently already.
+
 2020-04-23  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>
 
 	* config/arm/arm_mve.h (__arm_vbicq_n_u16): Modify function parameter's
diff --git a/gcc/config/rs6000/rs6000-call.c b/gcc/config/rs6000/rs6000-call.c
index a9ae7ab70ca..d4875ddeeb5 100644
--- a/gcc/config/rs6000/rs6000-call.c
+++ b/gcc/config/rs6000/rs6000-call.c
@@ -5739,14 +5739,15 @@ rs6000_discover_homogeneous_aggregate (machine_mode mode, const_tree type,
 		*n_elts = field_count;
 	      if (cxx17_empty_base_seen && warn_psabi)
 		{
-		  static const_tree last_reported_type;
-		  if (type != last_reported_type)
+		  static unsigned last_reported_type_uid;
+		  unsigned uid = TYPE_UID (TYPE_MAIN_VARIANT (type));
+		  if (uid != last_reported_type_uid)
 		    {
 		      inform (input_location,
 			      "parameter passing for argument of type %qT "
 			      "when C++17 is enabled changed to match C++14 "
 			      "in GCC 10.1", type);
-		      last_reported_type = type;
+		      last_reported_type_uid = uid;
 		    }
 		}
 	      return true;