[gcc r11-8601] Bacported from trunk:

[gcc r11-8601] Bacported from trunk:

[Martin Sebor]

https://gcc.gnu.org/g:11133f8f113e4591a2a5c9e61d810b9e5931043e

commit r11-8601-g11133f8f113e4591a2a5c9e61d810b9e5931043e
Author: Martin Sebor <msebor@redhat.com>
Date:   Thu Jun 17 10:32:00 2021 -0600

    Bacported from trunk:
    
    PR middle-end/100574 - ICE in size_remaining, at builtins.c
    
    gcc/ChangeLog:
            PR middle-end/100574
            * builtins.c (access_ref::get_ref): Improve detection of PHIs with
            all null arguments.
    
    gcc/testsuite/ChangeLog:
            PR middle-end/100574
            * g++.dg/pr100574.C: New test.

Diff:
---
 gcc/builtins.c                  | 18 ++++++------
 gcc/testsuite/g++.dg/pr100574.C | 64 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 9 deletions(-)

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 1bfffe7081b..4c2ed1cb143 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -364,15 +364,6 @@ access_ref::get_ref (vec<access_ref> *all_refs,
 	same_ref.offrng[1] = phi_arg_ref.offrng[1];
     }
 
-  if (phi_ref.sizrng[0] < 0)
-    {
-      /* Fail if none of the PHI's arguments resulted in updating PHI_REF
-	 (perhaps because they have all been already visited by prior
-	 recursive calls).  */
-      psnlim->leave_phi (ref);
-      return NULL_TREE;
-    }
-
   if (!same_ref.ref && same_ref.offrng[0] != 0)
     /* Clear BASE0 if not all the arguments refer to the same object and
        if not all their offsets are zero-based.  This allows the final
@@ -392,6 +383,15 @@ access_ref::get_ref (vec<access_ref> *all_refs,
       phi_ref.parmarray = parmarray;
     }
 
+  if (phi_ref.sizrng[0] < 0)
+    {
+      /* Fail if none of the PHI's arguments resulted in updating PHI_REF
+	 (perhaps because they have all been already visited by prior
+	 recursive calls).  */
+      psnlim->leave_phi (ref);
+      return NULL_TREE;
+    }
+
   /* Avoid changing *THIS.  */
   if (pref && pref != this)
     *pref = phi_ref;
diff --git a/gcc/testsuite/g++.dg/pr100574.C b/gcc/testsuite/g++.dg/pr100574.C
new file mode 100644
index 00000000000..42ba0404a28
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr100574.C
@@ -0,0 +1,64 @@
+/* PR middle-end/100574 - ICE: in size_remaining, at builtins.c:413 with
+   -O3 -ftracer -fno-tree-dominator-opts -fno-tree-fre
+   { dg-do compile { target c++11 } }
+   { dg-options "-O3 -ftracer -fno-tree-dominator-opts -fno-tree-fre" } */
+
+void *operator new (__SIZE_TYPE__, void *__p) { return __p; }
+
+template <typename> struct allocator_traits;
+template <typename> class allocator {};
+template <typename _Tp> struct allocator_traits<allocator<_Tp> >
+{
+  using allocator_type = allocator<_Tp>;
+  using pointer = _Tp *;
+  using size_type = long;
+  template <typename _Up> using rebind_alloc = allocator<_Up>;
+  static pointer allocate(allocator_type, size_type);
+  template <typename _Up> static void construct(_Up __p) { new (__p) _Up(); }
+};
+
+struct __alloc_traits : allocator_traits<allocator<char>> {
+  struct rebind {
+    typedef rebind_alloc<char> other;
+  };
+};
+
+struct _Vector_base {
+  struct : __alloc_traits::rebind::other {
+  } _M_impl;
+  long _M_allocate___n;
+};
+
+template <typename, typename = char> class vector : _Vector_base {
+  long max_size();
+public:
+  void push_back() { _M_realloc_insert(); }
+  template <typename...> void _M_realloc_insert();
+};
+
+template <typename _Tp, typename _Alloc>
+template <typename...>
+void vector<_Tp, _Alloc>::_M_realloc_insert() {
+  __alloc_traits::pointer __trans_tmp_5;
+  long __len(__len || max_size()), __elems_before;
+  __trans_tmp_5 = _M_allocate___n
+    ? __alloc_traits::allocate(_M_impl, _M_allocate___n)
+    : __alloc_traits::pointer();
+  __alloc_traits::construct(__trans_tmp_5 + __elems_before);
+}
+
+enum { MIDIST_PITCHBEND };
+struct DataBlock {
+  vector<char> data;
+};
+
+char ReadTrackChunk_status;
+
+void ReadTrackChunk()
+{
+  DataBlock block;
+  while (!0)
+    switch (ReadTrackChunk_status)
+    case MIDIST_PITCHBEND:
+      block.data.push_back();
+}