From: Richard Biener <rguenther@suse.de>
Date: Mon, 13 Jun 2016 07:34:45 +0000 (+0000)
Subject: re PR middle-end/64516 (arm: wrong unaligned load generated)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f57f53d3a5a0b18fdf5cef76247aed5f4b1e5610;p=gcc.git

re PR middle-end/64516 (arm: wrong unaligned load generated)

2016-06-13  Richard Biener  <rguenther@suse.de>

	PR middle-end/64516
	* fold-const.c (fold_unary_loc): Preserve alignment when
	folding a VIEW_CONVERT_EXPR into a MEM_REF.

	* gcc.dg/align-3.c: New testcase.

From-SVN: r237355
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3ea7a014f5a..690bd02469d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-06-13  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/64516
+	* fold-const.c (fold_unary_loc): Preserve alignment when
+	folding a VIEW_CONVERT_EXPR into a MEM_REF.
+
 2016-06-13  Martin Liska  <mliska@suse.cz>
 
 	PR sanitizer/71458
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 7f8803ca57d..1a464ec8366 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -7975,6 +7975,8 @@ fold_unary_loc (location_t loc, enum tree_code code, tree type, tree op0)
     case VIEW_CONVERT_EXPR:
       if (TREE_CODE (op0) == MEM_REF)
         {
+	  if (TYPE_ALIGN (TREE_TYPE (op0)) != TYPE_ALIGN (type))
+	    type = build_aligned_type (type, TYPE_ALIGN (TREE_TYPE (op0)));
 	  tem = fold_build2_loc (loc, MEM_REF, type,
 				 TREE_OPERAND (op0, 0), TREE_OPERAND (op0, 1));
 	  REF_REVERSE_STORAGE_ORDER (tem) = REF_REVERSE_STORAGE_ORDER (op0);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f3245154d77..a596a54e275 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-06-13  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/64516
+	* gcc.dg/align-3.c: New testcase.
+
 2016-06-13  Martin Liska  <mliska@suse.cz>
 
 	* gcc.target/i386/pr71458.c: New test.
diff --git a/gcc/testsuite/gcc.dg/align-3.c b/gcc/testsuite/gcc.dg/align-3.c
new file mode 100644
index 00000000000..5c97d5ac3cc
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/align-3.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-rtl-expand" } */
+
+typedef struct { char a[2]; } __attribute__((__packed__)) TU2;
+unsigned short get16_unaligned(const void *p) {
+    unsigned short v;
+    *(TU2 *)(void *)(&v) = *(const TU2 *)p;
+    return v;
+}
+
+/* { dg-final { scan-rtl-dump "MEM\[^\n\r\]*A8\\\]" "expand" } } */