[gcc r12-3673] Handle null cfun [PR102243].

[Martin Sebor]

https://gcc.gnu.org/g:c3895ef466f3068cac6f5c18b55716f494484917

commit r12-3673-gc3895ef466f3068cac6f5c18b55716f494484917
Author: Martin Sebor <msebor@redhat.com>
Date:   Sun Sep 19 17:16:26 2021 -0600

    Handle null cfun [PR102243].
    
    Resolves:
    PR middle-end/102243 - ICE on placement new at global scope
    
    gcc/ChangeLog:
            PR middle-end/102243
            * tree-ssa-strlen.c (get_range): Handle null cfun.
    
    gcc/testsuite/ChangeLog:
            PR middle-end/102243
            * g++.dg/warn/Wplacement-new-size-10.C: New test.

Diff:
---
 gcc/testsuite/g++.dg/warn/Wplacement-new-size-10.C | 13 +++++++++++++
 gcc/tree-ssa-strlen.c                              | 14 ++++++++++----
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/gcc/testsuite/g++.dg/warn/Wplacement-new-size-10.C b/gcc/testsuite/g++.dg/warn/Wplacement-new-size-10.C
new file mode 100644
index 00000000000..6b71a832a30
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wplacement-new-size-10.C
@@ -0,0 +1,13 @@
+/* PR middle-end/102243 - ICE on placement new at global scope
+   { dg-do compile }
+   { dg-options "-Wall" } */
+
+void *operator new (__SIZE_TYPE__, void *);
+
+char a[2][sizeof (int)];
+
+int *p = new (a[1]) int;
+
+void *operator new[] (__SIZE_TYPE__, void *p) { return p; }
+
+int *q = new (a[1]) int[1];
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c
index 7c93958e9ad..7c568a42d49 100644
--- a/gcc/tree-ssa-strlen.c
+++ b/gcc/tree-ssa-strlen.c
@@ -199,16 +199,22 @@ static bool handle_assign (gimple_stmt_iterator *, tree, bool *,
 
 /* Sets MINMAX to either the constant value or the range VAL is in
    and returns either the constant value or VAL on success or null
-   when the range couldn't be determined.  Uses RVALS when nonnull
-   to determine the range, otherwise uses CFUN or global range info,
-   whichever is nonnull.  */
+   when the range couldn't be determined.  Uses RVALS or CFUN for
+   range info, whichever is nonnull.  */
 
 tree
 get_range (tree val, gimple *stmt, wide_int minmax[2],
 	   range_query *rvals /* = NULL */)
 {
   if (!rvals)
-    rvals = get_range_query (cfun);
+    {
+      if (!cfun)
+	/* When called from front ends for global initializers CFUN
+	   may be null.  */
+	return NULL_TREE;
+
+      rvals = get_range_query (cfun);
+    }
 
   value_range vr;
   if (!rvals->range_of_expr (vr, val, stmt))