invoke.texi (-fstrict-aliasing): Document.

	* invoke.texi (-fstrict-aliasing): Document.
	* rtl.texi (MEM_ALIAS_SET): Document.
	* flags.h (flag_strict_aliasing): Declare.
	* toplev.c (flag_strict_aliasing): Define.
	(f_options): Add -strict-aliasing.
	(main): Set flag_strict_aliasing if -O2 or higher.
	* tree.h (tree_type): Add alias_set field.
	(TYPE_ALIAS_SET): New macro.
	(TYPE_ALIAS_SET_KNOWN_P): Likewise.
	(get_alias_set): Declare.
	* tree.c (lang_get_alias_set): Define.
	(make_node): Initialize TYPE_ALIAS_SET.
	(get_alias_set): New function.
	* print-tree.c (print_node): Dump the alias set for a type.
	* c-tree.h (c_get_alias_set): Declare.
	* c-common.c (c_get_alias_set): New function.
	* c-decl.c (init_decl_processing): Set lang_get_alias_set.
	* expr.c (protect_from_queue): Propogage alias sets.
	(expand_assignment): Calculate alias set for new MEMs.
	(expand_expr): Likewise.
	* function.c (put_var_into_stack): Likewise.
	(put_reg_into_stack): Likewise.
	(gen_mem_addressof): Likewise.
	(assign_parms): Likewise.
	* stmt.c (expand_decl): Likewise.
	* varasm.c (make_decl_rtl): Eliminate redundant clearing of
	DECL_RTL.  Calculate alias set for new MEMs.
	* rtl.def (REG): Add dummy operand.
	(MEM): Add extra operand to store the MEM_ALIAS_SET.
	* rtl.h (MEM_ALIAS_SET): New macro.
	(gen_rtx_MEM): Declare.
	* emit-rtl.c (gen_rtx_MEM): New function.
	* gengenrtl.c (sepcial_rtx): Make MEMs special.
	* alias.c (CHECK_ALIAS_SETS_FOR_CONSISTENCY): New macro.
	(DIFFERENT_ALIAS_SETS_P): Likewise.
	(canon_rtx): Propogate the alias set to the new MEM.
	(true_dependence): Check the alias sets.
	(anti_dependence): Likewise.
	(output_dependence): Likewise.
	* explow.c (stabilize): Progoate alias sets.
	* integrate.c (copy_rtx_and_substitute): Likewise.
	* final.c (alter_subreg): Make sure not to leave MEM_IN_STRUCT_P
	in an unpredictable state.  Propogate alias sets.
	* reload1.c (reload): Clear MEM_ALIAS_SET for new MEMs about which
	we have no alias information.

From-SVN: r20719

1 files changed, 4 insertions, 0 deletions

diff --git a/gcc/function.c b/gcc/function.c
index f8e3cd4..f3d33d0 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -1466,6 +1466,7 @@ put_var_into_stack (decl)
       /* Change the CONCAT into a combined MEM for both parts.  */
       PUT_CODE (reg, MEM);
       MEM_VOLATILE_P (reg) = MEM_VOLATILE_P (XEXP (reg, 0));
+      MEM_ALIAS_SET (reg) = get_alias_set (decl);
 
       /* The two parts are in memory order already.
 	 Use the lower parts address as ours.  */
@@ -1538,6 +1539,7 @@ put_reg_into_stack (function, reg, type, promoted_mode, decl_mode, volatile_p,
      case it was set for other reasons.  For instance, it is set for
      __builtin_va_alist.  */
   MEM_IN_STRUCT_P (reg) = AGGREGATE_TYPE_P (type) | MEM_IN_STRUCT_P (new);
+  MEM_ALIAS_SET (reg) = get_alias_set (type);
 
   /* Now make sure that all refs to the variable, previously made
      when it was a register, are fixed up to be valid again.  */
@@ -2735,6 +2737,7 @@ gen_mem_addressof (reg, decl)
   PUT_MODE (reg, DECL_MODE (decl));
   MEM_VOLATILE_P (reg) = TREE_SIDE_EFFECTS (decl);
   MEM_IN_STRUCT_P (reg) = AGGREGATE_TYPE_P (type);
+  MEM_ALIAS_SET (reg) = get_alias_set (decl);
 
   if (TREE_USED (decl) || DECL_INITIAL (decl) != 0)
     fixup_var_refs (reg, GET_MODE (reg), TREE_UNSIGNED (type));
@@ -3908,6 +3911,7 @@ assign_parms (fndecl, second_time)
 	     is readonly.  */
 	  MEM_IN_STRUCT_P (stack_parm) = aggregate;
 	  RTX_UNCHANGING_P (stack_parm) = TREE_READONLY (parm);
+	  MEM_ALIAS_SET (stack_parm) = get_alias_set (parm);
 	}
 
       /* If this parameter was passed both in registers and in the stack,