From 4790076933ef9337553c3fbbc52a93cce78c584f Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Mon, 27 May 2024 09:13:11 +0200
Subject: [PATCH] tree-optimization/115232 - demangle failure during -Waccess

For the following testcase we fail to demangle
_ZZN5OuterIvE6methodIvEEvvQ3cstITL0__EEN5InnernwEm and
_ZZN5OuterIvE6methodIvEEvvQ3cstITL0__EEN5InnerdlEPv and in turn end
up building NULL references.  The following puts in a safeguard for
faile demangling into -Waccess.

	PR tree-optimization/115232
	* gimple-ssa-warn-access.cc (new_delete_mismatch_p): Handle
	failure to demangle gracefully.

	* g++.dg/pr115232.C: New testcase.

(cherry picked from commit 311d7f5c17b8969c7ed8e4f23178d6ec4752e33f)
---
 gcc/gimple-ssa-warn-access.cc   |  2 +-
 gcc/testsuite/g++.dg/pr115232.C | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/pr115232.C

diff --git a/gcc/gimple-ssa-warn-access.cc b/gcc/gimple-ssa-warn-access.cc
index dedaae27b31..194d1a2c02a 100644
--- a/gcc/gimple-ssa-warn-access.cc
+++ b/gcc/gimple-ssa-warn-access.cc
@@ -1762,7 +1762,7 @@ new_delete_mismatch_p (tree new_decl, tree delete_decl)
   void *np = NULL, *dp = NULL;
   demangle_component *ndc = cplus_demangle_v3_components (new_str, 0, &np);
   demangle_component *ddc = cplus_demangle_v3_components (del_str, 0, &dp);
-  bool mismatch = new_delete_mismatch_p (*ndc, *ddc);
+  bool mismatch = ndc && ddc && new_delete_mismatch_p (*ndc, *ddc);
   free (np);
   free (dp);
   return mismatch;
diff --git a/gcc/testsuite/g++.dg/pr115232.C b/gcc/testsuite/g++.dg/pr115232.C
new file mode 100644
index 00000000000..e1d96d8f899
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr115232.C
@@ -0,0 +1,25 @@
+// { dg-do compile }
+// { dg-require-effective-target c++20 }
+
+using size_t = decltype(sizeof(0));
+template <class U>
+static constexpr bool cst = true;
+template<class T>
+struct Outer
+{
+    Outer();
+    template <class U> void method() requires cst<U>
+    {
+        struct Inner
+        {
+            static void* operator new(size_t){return new char;}
+            static void operator delete(void*){}
+            Outer<void> t;
+        };
+        new Inner;
+    }
+};
+void f()
+{
+    Outer<void>{}.method<void>();
+}