re PR target/45212 (FAIL: gcc.target/alpha/pr24178.c scan-assembler ldl.*,18\\\\()

2010-08-09  Richard Guenther  <rguenther@suse.de>

	PR middle-end/45212
	* emit-rtl.c (set_mem_attributes_minus_bitpos): Adjust
	alignment from MEM_REF offset only if we took it from the
	base object.

	* gcc.target/i386/pr24178.c: New testcase.

From-SVN: r163029

gcc/ChangeLog

+2010-08-09  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/45212
+	* emit-rtl.c (set_mem_attributes_minus_bitpos): Adjust
+	alignment from MEM_REF offset only if we took it from the
+	base object.
+
 2010-08-09  Eric Fisher <joefoxreal@gmail.com>
 
 	* doc/sourcebuild.texi (vect_int_mult): Remove duplicate entry.

gcc/emit-rtl.c

@@ -1587,29 +1587,31 @@ set_mem_attributes_minus_bitpos (rtx ref, tree t, int objectp,
   else if (TREE_CODE (t) == MEM_REF)
     {
       tree op0 = TREE_OPERAND (t, 0);
-      unsigned HOST_WIDE_INT aoff = BITS_PER_UNIT;
-      if (host_integerp (TREE_OPERAND (t, 1), 1))
+      if (TREE_CODE (op0) == ADDR_EXPR
+	  && (DECL_P (TREE_OPERAND (op0, 0))
+	      || CONSTANT_CLASS_P (TREE_OPERAND (op0, 0))))
 	{
-	  unsigned HOST_WIDE_INT ioff = TREE_INT_CST_LOW (TREE_OPERAND (t, 1));
-	  aoff = (ioff & -ioff) * BITS_PER_UNIT;
-	}
-      if (TREE_CODE (op0) == ADDR_EXPR && DECL_P (TREE_OPERAND (op0, 0)))
-	align = MAX (align, DECL_ALIGN (TREE_OPERAND (op0, 0)));
-      else if (TREE_CODE (op0) == ADDR_EXPR
-	       && CONSTANT_CLASS_P (TREE_OPERAND (op0, 0)))
-	{
-	  align = TYPE_ALIGN (TREE_TYPE (TREE_OPERAND (op0, 0)));
+	  if (DECL_P (TREE_OPERAND (op0, 0)))
+	    align = DECL_ALIGN (TREE_OPERAND (op0, 0));
+	  else if (CONSTANT_CLASS_P (TREE_OPERAND (op0, 0)))
+	    {
+	      align = TYPE_ALIGN (TREE_TYPE (TREE_OPERAND (op0, 0)));
 #ifdef CONSTANT_ALIGNMENT
-	  align = CONSTANT_ALIGNMENT (TREE_OPERAND (op0, 0), align);
+	      align = CONSTANT_ALIGNMENT (TREE_OPERAND (op0, 0), align);
 #endif
+	    }
+	  if (TREE_INT_CST_LOW (TREE_OPERAND (t, 1)) != 0)
+	    {
+	      unsigned HOST_WIDE_INT ioff
+		= TREE_INT_CST_LOW (TREE_OPERAND (t, 1));
+	      unsigned HOST_WIDE_INT aoff = (ioff & -ioff) * BITS_PER_UNIT;
+	      align = MIN (aoff, align);
+	    }
 	}
       else
 	/* ??? This isn't fully correct, we can't set the alignment from the
 	   type in all cases.  */
 	align = MAX (align, TYPE_ALIGN (type));
-
-      if (!integer_zerop (TREE_OPERAND (t, 1)) && aoff < align)
-	align = aoff;
     }
 
   else if (TREE_CODE (t) == MISALIGNED_INDIRECT_REF)

gcc/testsuite/ChangeLog

+2010-08-09  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/45212
+	* emit-rtl.c (set_mem_attributes_minus_bitpos): Adjust
+	alignment from MEM_REF offset only if we took it from the
+	base object.
+
+	* gcc.target/i386/pr24178.c: New testcase.
+
 2010-08-08  Uros Bizjak  <ubizjak@gmail.com>
 
 	* gcc.dg/20030107-1.c: Do not call cleanup-coverage-files.

gcc/testsuite/gcc.target/i386/pr24178.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-rtl-expand" } */
+
+struct S {
+    int l;
+    unsigned char c;
+};
+unsigned long f(unsigned char *p10) {
+    struct S *p = (struct S *) (p10 + 10);
+    return p->c;
+}
+
+/* The p->c memory access should have alignment of 4 bytes.  */
+
+/* { dg-final { scan-rtl-dump "MEM\[^\\n\]*A32" "expand" } } */
+/* { dg-final { cleanup-rtl-dump "expand" } } */