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[PATCH] Fix C++ ref op= ICE in the gimplifier with -g (PR c++/84704)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Richard Biener <rguenther at suse dot de>, Jason Merrill <jason at redhat dot com>, Alexandre Oliva <aoliva at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 5 Mar 2018 21:27:27 +0100
- Subject: [PATCH] Fix C++ ref op= ICE in the gimplifier with -g (PR c++/84704)
- Authentication-results: sourceware.org; auth=none
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
The following testcase ICEs, because ARRAY_REF on lhs of op=
has a statement list with no side-effects as index (containing
DEBUG_BEGIN_STMT and integer_zero_node), stabilize_reference
does nothing to it (as it has no side-effects), then the array ref
is unshared in unshare_body (mostly_copy_tree_r, which copies
ARRAY_REF, but doesn't copy STATEMENT_LIST) and finally gimplifier
when processing the first ARRAY_REF destroys the STATEMENT_LIST
(moves the 0; out of it and voidifies the rest) and finally when gimplifying
the second ARRAY_REF we ICE because the index has void type.
The following patch fixes it by forcing SAVE_EXPR for STATEMENT_LIST
even when it doesn't have side-effects, that way even the DEBUG_BEGIN_STMTs
are emitted just once rather than multiple times and we don't really need
to unshare it specially.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2018-03-05 Jakub Jelinek <jakub@redhat.com>
PR c++/84704
* tree.c (stabilize_reference_1): Return save_expr (e) for
STATEMENT_LIST even if it doesn't have side-effects.
* g++.dg/debug/pr84704.C: New test.
--- gcc/tree.c.jj 2018-02-22 12:37:02.634387690 +0100
+++ gcc/tree.c 2018-03-05 10:50:54.355557537 +0100
@@ -4352,6 +4352,11 @@ stabilize_reference_1 (tree e)
switch (TREE_CODE_CLASS (code))
{
case tcc_exceptional:
+ /* Always wrap STATEMENT_LIST into SAVE_EXPR, even if it doesn't
+ have side-effects. */
+ if (code == STATEMENT_LIST)
+ return save_expr (e);
+ /* FALLTHRU */
case tcc_type:
case tcc_declaration:
case tcc_comparison:
--- gcc/testsuite/g++.dg/debug/pr84704.C.jj 2018-03-05 11:52:37.558715635 +0100
+++ gcc/testsuite/g++.dg/debug/pr84704.C 2018-03-05 11:53:17.794720038 +0100
@@ -0,0 +1,11 @@
+// PR c++/84704
+// { dg-do compile }
+// { dg-options "-g -fcompare-debug -O2" }
+
+int a[1] = { 0 };
+
+void
+foo ()
+{
+ a[({ 0; })] %= 5;
+}
Jakub