- fix detection of overflow from multiply expressions.

[packages/gcc.git] / gcc-pr26565.patch

--- gcc/gcc/builtins.c	(revision 113409)
+++ gcc/gcc/builtins.c	(revision 113410)
@@ -275,14 +275,28 @@
 	case ADDR_EXPR:
 	  /* See what we are pointing at and look at its alignment.  */
 	  exp = TREE_OPERAND (exp, 0);
+	  inner = max_align;
+	  while (handled_component_p (exp))
+	    {
+	      /* Fields in a structure can be packed, honour DECL_ALIGN
+		 of the FIELD_DECL.  For all other references the conservative 
+		 alignment is the element type alignment.  */
+	      if (TREE_CODE (exp) == COMPONENT_REF)
+		inner = MIN (inner, DECL_ALIGN (TREE_OPERAND (exp, 1)));
+	      else
+		inner = MIN (inner, TYPE_ALIGN (TREE_TYPE (exp)));
+	      exp = TREE_OPERAND (exp, 0);
+	    }
 	  if (TREE_CODE (exp) == FUNCTION_DECL)
 	    align = FUNCTION_BOUNDARY;
 	  else if (DECL_P (exp))
-	    align = DECL_ALIGN (exp);
+	    align = MIN (inner, DECL_ALIGN (exp));
 #ifdef CONSTANT_ALIGNMENT
 	  else if (CONSTANT_CLASS_P (exp))
-	    align = CONSTANT_ALIGNMENT (exp, align);
+	    align = MIN (inner, (unsigned)CONSTANT_ALIGNMENT (exp, align));
 #endif
+	  else
+	    align = MIN (align, inner);
 	  return MIN (align, max_align);
 
 	default: