From: Richard Biener <rguenther@suse.de>
Date: Fri, 8 Dec 2017 14:45:30 +0000 (+0000)
Subject: re PR middle-end/81782 (Yet another -Wmaybe-uninitialized false positive with empty... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=68e6d5a6bdd07248e78eccbd19eb282a9531fd7c;p=gcc.git

re PR middle-end/81782 (Yet another -Wmaybe-uninitialized false positive with empty array)

2017-12-08  Richard Biener  <rguenther@suse.de>

	PR middle-end/81782
	* tree-ssa-uninit.c (warn_uninitialized_vars): Properly
	handle accesses outside of zero-sized vars.

	* gcc.dg/uninit-pr81782.c: New testcase.

From-SVN: r255512
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8184c66e8c8..bf4dc004994 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-12-08  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/81782
+	* tree-ssa-uninit.c (warn_uninitialized_vars): Properly
+	handle accesses outside of zero-sized vars.
+
 2017-12-08  Martin Jambor  <mjambor@suse.cz>
 
 	PR tree-optimization/83141
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d9ce35fb233..6a68ea6e965 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-12-08  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/81782
+	* gcc.dg/uninit-pr81782.c: New testcase.
+
 2017-12-08  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* g++.dg/opt/pr83252.C: Add -mclear-hwcap on *-*-solaris*.
diff --git a/gcc/testsuite/gcc.dg/uninit-pr81782.c b/gcc/testsuite/gcc.dg/uninit-pr81782.c
new file mode 100644
index 00000000000..7d1e90203f0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/uninit-pr81782.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-Wmaybe-uninitialized" } */
+
+int
+foo (void)
+{
+  char empty_array[] = { };
+  int i, ret = 0;
+
+  for (i = 0; i < (int) (sizeof (empty_array) / sizeof (empty_array[0])); i++)
+    ret = empty_array[i]; /* { dg-bogus "uninitialized" } */
+
+  return ret;
+}
diff --git a/gcc/tree-ssa-uninit.c b/gcc/tree-ssa-uninit.c
index 4096ded7ea2..b17b2b10e52 100644
--- a/gcc/tree-ssa-uninit.c
+++ b/gcc/tree-ssa-uninit.c
@@ -296,8 +296,8 @@ warn_uninitialized_vars (bool warn_possibly_uninitialized)
 	         variable.  */
 	      if (DECL_P (base)
 		  && ref.size != -1
-		  && ref.max_size == ref.size
-		  && (ref.offset + ref.size <= 0
+		  && ((ref.max_size == ref.size
+		       && ref.offset + ref.size <= 0)
 		      || (ref.offset >= 0
 			  && DECL_SIZE (base)
 			  && TREE_CODE (DECL_SIZE (base)) == INTEGER_CST