From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 30 Aug 2019 12:33:40 +0000 (+0200)
Subject: backport: re PR c/89872 (GCC does not generate read access to volatile compound literal)
X-Git-Tag: releases/gcc-7.5.0~219
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=da2620146d5d918106371eb92544367c575d50e2;p=thirdparty%2Fgcc.git

backport: re PR c/89872 (GCC does not generate read access to volatile compound literal)

	Backported from mainline
	2019-03-29  Jakub Jelinek  <jakub@redhat.com>

	PR c/89872
	* gimplify.c (gimplify_compound_literal_expr): Don't optimize a
	non-addressable complit into its initializer if it is volatile.

	* gcc.dg/tree-ssa/pr89872.c: New test.

From-SVN: r275144
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3832f25eed7f..ad1c2881b53d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,12 @@
 2019-08-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2019-03-29  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/89872
+	* gimplify.c (gimplify_compound_literal_expr): Don't optimize a
+	non-addressable complit into its initializer if it is volatile.
+
 	2019-03-28  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/89621
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 8cc081e83117..0e92ffe4ea2c 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -4498,6 +4498,7 @@ gimplify_compound_literal_expr (tree *expr_p, gimple_seq *pre_p,
      otherwise we'd generate a new temporary, and we can as well just
      use the decl we already have.  */
   else if (!TREE_ADDRESSABLE (decl)
+	   && !TREE_THIS_VOLATILE (decl)
 	   && init
 	   && (fallback & fb_lvalue) == 0
 	   && gimple_test_f (init))
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0a2b800f679f..0f6129a4ba23 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2019-08-30  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2019-03-29  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/89872
+	* gcc.dg/tree-ssa/pr89872.c: New test.
+
 	2019-03-28  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/89621
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89872.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89872.c
new file mode 100644
index 000000000000..c081cd5f9ec0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89872.c
@@ -0,0 +1,27 @@
+/* PR c/89872 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-times " ={v} 1;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " ={v} 2;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " ={v} 3;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " ={v} 4;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " ={v} 0;" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times " ={v} " 10 "optimized" } } */
+
+void
+foo (void)
+{
+  (volatile int){1} + (volatile int){2};
+}
+
+void
+bar (void)
+{
+  (volatile int){3};
+}
+
+void
+baz (void)
+{
+  (volatile int){4} / (volatile int){0};
+}