From: Eric Botcazou <ebotcazou@gcc.gnu.org>
Date: Fri, 30 Apr 2010 21:24:57 +0000 (+0000)
Subject: tree-ssa-loop-ivopts.c (may_be_unaligned_p): Check the alignment of the variable... 
X-Git-Tag: releases/gcc-4.3.5~70
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d1c1715817ee69570567c4cbd7496da4fbab2142;p=thirdparty%2Fgcc.git

tree-ssa-loop-ivopts.c (may_be_unaligned_p): Check the alignment of the variable part of the offset as well.

	* tree-ssa-loop-ivopts.c (may_be_unaligned_p): Check the alignment of
	the variable part of the offset as well.

From-SVN: r158953
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f1c2d133d9b8..2d1003ecb85c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2010-04-30  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* tree-ssa-loop-ivopts.c (may_be_unaligned_p): Check the alignment of
+	the variable part of the offset as well.
+
 2010-04-27  Richard Guenther  <rguenther@suse.de>
 
 	PR c++/40561
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b43e4b20997c..93a89110b605 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2010-04-30  DJ Delorie  <dj@redhat.com>
+
+	* gcc.c-torture/execute/20100430-1.c: New test.
+
 2010-04-27  Richard Guenther  <rguenther@suse.de>
 
 	PR c++/40561
diff --git a/gcc/testsuite/gcc.c-torture/execute/20100430-1.c b/gcc/testsuite/gcc.c-torture/execute/20100430-1.c
new file mode 100644
index 000000000000..d29c6fa1a37c
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20100430-1.c
@@ -0,0 +1,51 @@
+/* This used to generate unaligned accesses at -O2 because of IVOPTS.  */
+
+struct packed_struct
+{
+  struct packed_struct1
+  {
+    unsigned char cc11;
+    unsigned char cc12;
+  } __attribute__ ((packed)) pst1;
+  struct packed_struct2
+  {
+    unsigned char cc21;
+    unsigned char cc22;
+    unsigned short ss[104];
+    unsigned char cc23[13];
+  } __attribute__ ((packed)) pst2[4];
+} __attribute__ ((packed));
+
+typedef struct
+{
+  int ii;
+  struct packed_struct buf;
+} info_t;
+
+static unsigned short g;
+
+static void __attribute__((noinline))
+dummy (unsigned short s)
+{
+  g = s;
+}
+
+static int
+foo (info_t *info)
+{
+  int i, j;
+
+  for (i = 0; i < info->buf.pst1.cc11; i++)
+    for (j = 0; j < info->buf.pst2[i].cc22; j++)
+      dummy (info->buf.pst2[i].ss[j]);
+
+  return 0;
+}
+
+int main(void)
+{
+  info_t info;
+  info.buf.pst1.cc11 = 2;
+  info.buf.pst2[0].cc22 = info.buf.pst2[1].cc22 = 8;
+  return foo (&info);
+}
diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c
index 78b440906929..4f38266e9b05 100644
--- a/gcc/tree-ssa-loop-ivopts.c
+++ b/gcc/tree-ssa-loop-ivopts.c
@@ -1418,11 +1418,19 @@ may_be_unaligned_p (tree ref)
   base_type = TREE_TYPE (base);
   base_align = TYPE_ALIGN (base_type);
 
-  if (mode != BLKmode
-      && (base_align < GET_MODE_ALIGNMENT (mode)
-	  || bitpos % GET_MODE_ALIGNMENT (mode) != 0
-	  || bitpos % BITS_PER_UNIT != 0))
-    return true;
+  if (mode != BLKmode)
+    {
+      unsigned mode_align = GET_MODE_ALIGNMENT (mode);
+
+      if (base_align < mode_align
+	  || (bitpos % mode_align) != 0
+	  || (bitpos % BITS_PER_UNIT) != 0)
+	return true;
+
+      if (toffset
+	  && (highest_pow2_factor (toffset) * BITS_PER_UNIT) < mode_align)
+	return true;
+    }
 
   return false;
 }