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, 15 insertions, 2 deletions

diff --git a/gcc/rtl.h b/gcc/rtl.h
index bee83bb..af85d82 100644
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -561,6 +561,17 @@ extern char *note_insn_name[];
 /* For a MEM rtx, 1 if it refers to a field of an aggregate.  */
 #define MEM_IN_STRUCT_P(RTX) ((RTX)->in_struct)
 
+/* For a MEM rtx, the alias set.  If 0, this MEM is not in any alias
+   set, and may alias anything.  Otherwise, the MEM can only alias
+   MEMs in the same alias set.  This value is set in a
+   language-dependent manner in the front-end, and should not be
+   altered in the back-end.  These set numbers are tested for zero,
+   and compared for equality; they have no other significance.  In
+   some front-ends, these numbers may correspond in some way to types,
+   or other language-level entities, but they need not, and the
+   back-end makes no such assumptions.  */
+#define MEM_ALIAS_SET(RTX) (XINT (RTX, 1))
+
 /* For a LABEL_REF, 1 means that this reference is to a label outside the
    loop containing the reference.  */
 #define LABEL_OUTSIDE_LOOP_P(RTX) ((RTX)->in_struct)
@@ -1057,11 +1068,13 @@ extern rtx static_chain_incoming_rtx;
 #include "genrtl.h"
 #endif
 
-/* There are two RTL codes that require special attention; the generation
-   functions included above do the raw handling.  */
+/* There are some RTL codes that require special attention; the
+   generation functions included above do the raw handling.  If you
+   add to this list, modify special_rtx in gengenrtl.c as well.  */
 
 extern rtx gen_rtx_CONST_INT PROTO((enum machine_mode, HOST_WIDE_INT));
 extern rtx gen_rtx_REG PROTO((enum machine_mode, int));
+extern rtx gen_rtx_MEM PROTO((enum machine_mode, rtx));
 
 /* We need the cast here to ensure that we get the same result both with
    and without prototypes.  */