[gcc r13-3072] c++: fix debug info for array temporary [PR107154]

[Jason Merrill]

https://gcc.gnu.org/g:ce3a1b5976079b1467473b4628f05797fd2eae08

commit r13-3072-gce3a1b5976079b1467473b4628f05797fd2eae08
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Oct 4 17:06:04 2022 -0400

    c++: fix debug info for array temporary [PR107154]
    
    In the testcase the elaboration of the array init that happens at genericize
    time was getting the location info for the end of the function; fixed by
    doing the expansion at the location of the original expression.
    
            PR c++/107154
    
    gcc/cp/ChangeLog:
    
            * cp-gimplify.cc (cp_genericize_init_expr): Use iloc_sentinel.
            (cp_genericize_target_expr): Likewise.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/debug/dwarf2/lineno-array1.C: New test.

Diff:
---
 gcc/cp/cp-gimplify.cc                             |  2 ++
 gcc/testsuite/g++.dg/debug/dwarf2/lineno-array1.C | 25 +++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc
index cca3b9fea33..404a7699a72 100644
--- a/gcc/cp/cp-gimplify.cc
+++ b/gcc/cp/cp-gimplify.cc
@@ -920,6 +920,7 @@ cp_genericize_init (tree *replace, tree from, tree to)
 static void
 cp_genericize_init_expr (tree *stmt_p)
 {
+  iloc_sentinel ils = EXPR_LOCATION (*stmt_p);
   tree to = TREE_OPERAND (*stmt_p, 0);
   tree from = TREE_OPERAND (*stmt_p, 1);
   if (SIMPLE_TARGET_EXPR_P (from)
@@ -935,6 +936,7 @@ cp_genericize_init_expr (tree *stmt_p)
 static void
 cp_genericize_target_expr (tree *stmt_p)
 {
+  iloc_sentinel ils = EXPR_LOCATION (*stmt_p);
   tree slot = TARGET_EXPR_SLOT (*stmt_p);
   cp_genericize_init (&TARGET_EXPR_INITIAL (*stmt_p),
 		      TARGET_EXPR_INITIAL (*stmt_p), slot);
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/lineno-array1.C b/gcc/testsuite/g++.dg/debug/dwarf2/lineno-array1.C
new file mode 100644
index 00000000000..befac5f04b3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/lineno-array1.C
@@ -0,0 +1,25 @@
+// PR c++/107154
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-gno-as-loc-support -dA" }
+// Test that we emit debug info exactly once for the last line.
+// { dg-final { scan-assembler-times {:25:1} 1 } }
+
+bool dummy;
+
+struct S {
+  const char *p;
+  S(const char *p): p(p) {}
+  ~S() { dummy = true; }
+};
+
+using Sar = S[];
+
+struct X {
+  X(Sar&&) { }
+};
+
+int main()
+{
+  X x(Sar{"", ""});
+  return 0;
+}