public inbox for gcc-cvs@sourceware.org
help / color / mirror / Atom feed
* [gcc r12-7483] gimplify: Clear TREE_READONLY on automatic vars being stored into [PR104529]
@ 2022-03-04 14:15 Jakub Jelinek
0 siblings, 0 replies; only message in thread
From: Jakub Jelinek @ 2022-03-04 14:15 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:c85aaf2cbe9da50e23655a8082a37166adf4c0f7
commit r12-7483-gc85aaf2cbe9da50e23655a8082a37166adf4c0f7
Author: Jakub Jelinek <jakub@redhat.com>
Date: Fri Mar 4 15:14:59 2022 +0100
gimplify: Clear TREE_READONLY on automatic vars being stored into [PR104529]
The following testcase regressed when SRA started punting on stores to
TREE_READONLY vars. We document that:
"In a VAR_DECL, PARM_DECL or FIELD_DECL, or any kind of ..._REF node,
nonzero means it may not be the lhs of an assignment."
so the SRA change looks desirable. On the other side, at least in this
testcase the TREE_READONLY is set there intentionally from the
PR85873 fix, because gimplify_init_constructor itself uses TREE_READONLY
on the object to determine if it can perform promotion to static const
or not.
So, similarly to other spots in the gimplifier where we also clear
TREE_READONLY when we emit IL that stores into the object, this
does the same in gimplify_init_constructor, but in the way so that
the TREE_READONLY test for the promotion to static const keeps working
and doesn't change anything for notify_temp_creation mode, which doesn't
emit any IL, just tests if it would need a temporary or not.
This keeps PR85873 testcase working as before and fixes this regression.
2022-03-04 Jakub Jelinek <jakub@redhat.com>
PR middle-end/104529
* gimplify.cc (gimplify_init_constructor): Clear TREE_READONLY
on automatic objects which will be runtime initialized.
* g++.dg/tree-ssa/pr104529.C: New test.
Diff:
---
gcc/gimplify.cc | 11 +++++++++++
gcc/testsuite/g++.dg/tree-ssa/pr104529.C | 20 ++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index be8f0d3c76f..c6ba0c33480 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -5120,6 +5120,12 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
{
if (notify_temp_creation)
return GS_OK;
+
+ /* The var will be initialized and so appear on lhs of
+ assignment, it can't be TREE_READONLY anymore. */
+ if (VAR_P (object))
+ TREE_READONLY (object) = 0;
+
is_empty_ctor = true;
break;
}
@@ -5171,6 +5177,11 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
break;
}
+ /* The var will be initialized and so appear on lhs of
+ assignment, it can't be TREE_READONLY anymore. */
+ if (VAR_P (object) && !notify_temp_creation)
+ TREE_READONLY (object) = 0;
+
/* If there are "lots" of initialized elements, even discounting
those that are not address constants (and thus *must* be
computed at runtime), then partition the constructor into
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr104529.C b/gcc/testsuite/g++.dg/tree-ssa/pr104529.C
new file mode 100644
index 00000000000..3cb3853c22a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr104529.C
@@ -0,0 +1,20 @@
+// PR middle-end/104529
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2 -fdump-tree-optimized" }
+// { dg-final { scan-tree-dump-not "MEM\[^\n\r]*MEM" "optimized" } }
+
+#include <cstddef>
+#include <vector>
+
+struct S {
+ unsigned int a;
+ std::vector<unsigned char> b;
+ std::vector<unsigned char> c;
+};
+
+std::size_t
+foo ()
+{
+ S test[] = { { 48, { 255, 0, 0, 0, 0, 0 } } };
+ return sizeof (test);
+}
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2022-03-04 14:15 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-04 14:15 [gcc r12-7483] gimplify: Clear TREE_READONLY on automatic vars being stored into [PR104529] Jakub Jelinek
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).