From: Thomas Preud'homme <thomas.preudhomme@arm.com>
Date: Wed, 4 Feb 2015 08:22:45 +0000 (+0000)
Subject: re PR middle-end/62103 (Incorrect folding of bitfield in a union on big endian targets)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=cc9ef6a6419a8c343a5f0d233405411e8c5ca4cc;p=gcc.git

re PR middle-end/62103 (Incorrect folding of bitfield in a union on big endian targets)

2015-02-04  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/
    PR middle-end/62103
    * tree-ssa-sccvn.c (fully_constant_vn_reference_p): Use TYPE_PRECISION
    to compute size of referenced value in the constant case.

    gcc/testsuite/
    PR middle-end/62103
    * gcc.c-torture/execute/bitfld-7.c: New test adapted from bitfld-6.c
    to use 24 bits for bitfield b.

From-SVN: r220390
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fdea07e8a77..44aa27f6cfd 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2015-02-04  Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
+	PR middle-end/62103
+	* tree-ssa-sccvn.c (fully_constant_vn_reference_p): Use TYPE_PRECISION
+	to compute size of referenced value in the constant case.
+
 2015-02-03  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/64756
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ad2633b46fa..03585db3754 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2015-02-04  Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
+	PR middle-end/62103
+	* gcc.c-torture/execute/bitfld-7.c: New test adapted from bitfld-6.c
+	to use 24 bits for bitfield b.
+
 2015-02-04  Thomas Preud'homme  <thomas.preudhomme@arm.com>
 
 	PR testsuite/64796
diff --git a/gcc/testsuite/gcc.c-torture/execute/bitfld-7.c b/gcc/testsuite/gcc.c-torture/execute/bitfld-7.c
new file mode 100644
index 00000000000..e9a61df52f3
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/bitfld-7.c
@@ -0,0 +1,23 @@
+union U
+{
+  const int a;
+  unsigned b : 24;
+};
+
+static union U u = { 0x12345678 };
+
+/* Constant folding used to fail to account for endianness when folding a
+   union.  */
+
+int
+main (void)
+{
+#ifdef __BYTE_ORDER__
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+  return u.b - 0x345678;
+#else
+  return u.b - 0x123456;
+#endif
+#endif
+  return 0;
+}
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index 25c67d01a7a..0f1299affb8 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -1352,7 +1352,7 @@ fully_constant_vn_reference_p (vn_reference_t ref)
 	       || TYPE_PRECISION (ref->type) % BITS_PER_UNIT == 0))
     {
       HOST_WIDE_INT off = 0;
-      HOST_WIDE_INT size = tree_to_shwi (TYPE_SIZE (ref->type));
+      HOST_WIDE_INT size = TYPE_PRECISION (ref->type);
       if (size % BITS_PER_UNIT != 0
 	  || size > MAX_BITSIZE_MODE_ANY_MODE)
 	return NULL_TREE;