tree-ssa.texi: Remove references to VDEF and add descriptions of V_MAY_DEF and V_MUST_DEF.

	* doc/tree-ssa.texi: Remove references to VDEF and add descriptions
	of V_MAY_DEF and V_MUST_DEF.
	* tree-dfa.c (dfa_stats_d): Add num_v_must_defs and rename
	num_vdefs to num_v_may_defs.
	(compute_immediate_uses_for_stmt): Rename occurences of vdef
	to v_may_def.
	(redirect_immediate_uses): Ditto.
	(dump_dfa_stats): Ditto. Also added code to dump num_v_must_defs.
	(collect_dfa_stats_r): Rename occurences of vdef to v_may_def.
	Also add code to sum up the number of v_must_defs.
	(vdefs_disappeared_p): Replace with...
	(v_may_defs_disappeared_p): This.
	(v_must_defs_disappeared_p): New function.
	(mark_new_vars_to_rename): Rename occurences of vdef to v_may_def.
	Also add code to mark new variables found in V_MUST_DEFs for
	renameing.
	* tree-flow.h (stmt_ann_d): Add v_must_def_ops and replace
	vdef_ops to v_may_def_ops.
	(get_vdef_ops): Replace with...
	(get_v_may_def_ops): This.
	* tree-flow-inline.h (get_vdef_ops): Replace with...
	(get_v_may_def_ops): This.
	(get_v_must_def_ops): New function.
	(get_vdef_result_ptr): Replace with...
	(get_v_may_def_result_ptr): This.
	(get_vdef_op_ptr): Ditto with...
	(get_v_may_def_op_ptr); This.
	(get_v_must_def_op_ptr): New function.
	* tree-into-ssa.c (mark_def_sites): Rename occurences of vdef
	to v_may_def. Also add code to mark statements with
	V_MUST_DEFs as definition sites.
	(rewrite_stmt): Rename occurences of vdef to v_may_def. Also
	add code to register new V_MUST_DEFs made by the statement.
	* tree-outof-ssa.c (VIRTUAL_PARTITION): Update comments.
	(check_replaceable): Rename occurences of vdef to v_may_def. Also
	add check for V_MUST_DEFs.
	(find_replaceable_in_bb): Ditto.
	* tree-pretty-print.c (dump_vops): Rename occurences of vdef
	to v_may_def. Also add code to dump V_MUST_DEFs.
	* tree-sra.c (mark_all_vdefs): Replace with...
	(mark_all_v_may_defs): This.
	(mark_all_v_must_defs): New function.
	(create_scalar_copies): Replace call to mark_all_vdefs with
	calls to mark_all_v_may_defs and mark_all_v_must_defs.
	(scalarize_structures): Rename occurences of vdef to v_may_def.
	Also add a check for V_MUST_DEFs.
	(scalarize_modify_expr): Rename occurences of vdef to v_may_def.
	* tree-ssa-alias.c (global_var): Update comment.
	(compute_may_aliases): Ditto.
	(compute_points_to_and_addr_escape): Rename occurences of vdef
	to v_may_def. Also add code to mark variables in V_MUST_DEF
	operands as being written to.
	(group_aliases): Update comment.
	(maybe_create_global_var): Ditto.
	* tree-ssa.c (verify_ssa): Rename occurences of vdef to v_may_def.
	Also add a check for V_MUST_DEFs on GIMPLE registers.
	(replace_immediate_uses): Rename occurences of vdef to v_may_def.
	* tree-ssa-ccp.c (visit_stmt): Rename occurences of vdef
	to v_may_def. Also add code to mark all V_MUST_DEF operands
	VARYING.
	(initialize): Ditto.
	(set_rhs): Rename occurences of vdef to v_may_def. Also add
	code to update SSA_NAMEs in V_MUST_DEFs.
	* tree-ssa-copy.c (cprop_into_stmt): Rename occurences of vdef
	to v_may_def.
	* tree-ssa-dce.c (mark_stmt_if_obviously_necessary): Rename
	occurences of vdef to v_may_def. Also add code to mark statements
	with V_MUST_DEFs as necessary.
	(propagate_necessity): Rename occurences of vdef to v_may_def.
	* tree-ssa-dom.c (redirect_edges_and_update_ssa_graph): Rename
	occurences of vdef to v_may_def. Also add code to mark operands
	in V_MUST_DEFs for renaming.
	(eliminate_redundant_computations): Rename occurences of vdef
	to v_may_def.
	(record_equivalences_from_stmt): Rename occurences of vdef
	to v_may_def. Also add code to record VUSEs for V_MUST_DEFs.
	(optimize_stmt): Remove unnesessary variable vdefs. Update
	comment.
	(register_definitions_for_stmt): Rename occurences of vdef
	to v_may_def. Also add code to register definitions made with
	V_MUST_DEFs.
	* tree-ssa-dse.c (fix_stmt_vdefs): Replace with...
	(fix_stmt_v_may_defs): This.
	(fix_phi_uses): Rename occurences of vdef to v_may_def.
	(dse_optimize_stmt): Ditto.
	* tree-ssa-live.c (create_ssa_var_map): Rename occurences of vdef
	to v_may_def. Also add code to mark V_MUST_DEF operands as being
	used in virtual operators.
	* tree-ssa-loop.c (mark_defs_for_rewrite): Rename occurences of
	vdef to v_may_def. Also add code to mark V_MUST_DEF operands for
	renaming.
	* tree-ssa-operands.c (opf_kill_def): New flag for killing
	definitions.
	(build_vdefs): Renamed to...
	(build_v_may_defs): This.
	(build_v_must_defs): New variable.
	(voperands_d): Add v_must_def_ops and replace vdef_ops with
	v_may_def_ops.
	(append_vdef): Replace with...
	(append_v_may_def): This.
	(append_v_must_def): New function.
	(NUM_FREE): Increment for V_MUST_DEF
	(optype_freelist): Increment its size for V_MUST_DEF
	(allocate_vdef_optype): Replace with...
	(allocate_v_may_def_optype): This.
	(allocate_v_must_def_optype): New function.
	(free_vdefs): Replace with...
	(free_v_may_defs): This.
	(free_v_must_defs): New function.
	(remove_vdefs): Replace with...
	(remove_v_may_defs): This.
	(remove_v_must_defs): New function.
	(init_ssa_operands): Rename occurences of vdef to v_may_def. Also
	add code to initialize build_v_must_defs.
	(finalize_ssa_vdefs): Replace with...
	(finalize_ssa_v_may_defs): This.
	(finalize_ssa_vuses): Rename occurences of vdef to v_may_def.
	(finalize_ssa_v_must_defs): New function.
	(finalize_ssa_stmt_operands): Replace call to finalize_ssa_vdefs
	with calls to finalize_ssa_v_may_defs and finalize_ssa_v_must_defs.
	(verify_start_operands): Rename occurences of vdef to v_may_def.
	Also add check for build_v_must_defs.
	(get_stmt_operands): Rename occurences of vdef to v_may_def.
	Also add code to handle V_MUST_DEFs and to use opf_kill_def for
	killing definitions.
	(get_expr_operands): Update comment and use opf_kill_def for
	killing definitions.
	(add_stmt_operand): Replace code that appends VDEFs with code
	that appends V_MUST_DEFs when opf_kill_def is set and V_MAY_DEFs
	otherwise.
	(add_call_clobber_ops): Update comments.
	* tree-ssa-operands.h (vdef_optype_d): Replace with...
	(v_may_def_optype_d): This.
	(v_must_def_optype_d): New structure.
	(VDEF_OPS): Replace with...
	(V_MAY_DEF_OPS): This.
	(STMT_VDEF_OPS): Same with...
	(STMT_V_MAY_DEF_OPS): This.
	(NUM_VDEFS): And...
	(NUM_V_MAY_DEFS): This.
	(VDEF_RESULT_PTR): As well as...
	(V_MAY_DEF_RESULT_PTR): This.
	(VDEF_RESULT): Same goes for...
	(V_MAY_DEF_RESULT): This.
	(VDEF_OP_PTR): And...
	(V_MAY_DEF_OP_PTR): This.
	(VDEF_OP): And...
	(V_MAY_DEF_OP): This.
	(V_MUST_DEF_OPS): New macro.
	(STMT_V_MUST_DEF_OPS): Ditto.
	(NUM_V_MUST_DEFS): Ditto.
	(V_MUST_DEF_OP_PTR): Ditto.
	(V_MUST_DEF_OP): Ditto.
	(remove_vdefs): Replace signature with...
	(remove_v_may_defs): This.
	(remove_v_must_defs): New function signature.
	* tree-ssa-pre.c (subst_phis): Replace call to remove_vdefs
	with calls to remove_v_may_defs and remove_v_must_defs.
	(process_left_occs_and_kills): Rename occurences of vdef to v_may_def.
	Also add code that marks left occurences of operands in V_MUST_DEFs.
	* tree-tailcall.c (find_tail_calls): Rename occurences of vdef
	to v_may_def. Also add check for V_MUST_DEFs.
	(eliminate_tail_call):Rename occurences of vdef to v_may_def.

testsuite:

	* gcc.dg/tree-ssa/20031015-1.c: Scan for
	V_MAY_DEF instead of VDEF.
	* gcc.dg/tree-ssa/20040517-1.c: Ditto.

From-SVN: r82947

1 files changed, 31 insertions, 17 deletions

diff --git a/gcc/doc/tree-ssa.texi b/gcc/doc/tree-ssa.texi
index 56ccd61..a22b494 100644
--- a/gcc/doc/tree-ssa.texi
+++ b/gcc/doc/tree-ssa.texi
@@ -697,8 +697,17 @@ variable @code{b} is completely modified with the contents of
 variable @code{a}.  Real definition are also known as @dfn{killing
 definitions}.  Similarly, the use of @code{a} reads all its bits.
 
-In contrast, virtual operands represent partial or ambiguous
-references to a variable.  For instance, given
+In contrast, virtual operands are used with variables that can have
+a partial or ambiguous reference. This includes structures, arrays,
+globals, and aliased variables. In these cases, we have two types of
+definitions. For globals, structures, and arrays, we can determine from
+a statement whether a variable of these types has a killing definition. 
+If the variable does, then the statement is marked as having a
+@dfn{must definition} of that variable. However, if a statement is only
+defining a part of the variable (ie. a field in a structure), or if we
+know that a statement might define the variable but we cannot say for sure,
+then we mark that statement as having a @dfn{may definition}.  For 
+instance, given
 
 @smallexample
 @{
@@ -730,8 +739,8 @@ operands, use the @option{-vops} option to @option{-fdump-tree}:
     p = &a;
   else
     p = &b;
-  # a = VDEF <a>
-  # b = VDEF <b>
+  # a = V_MAY_DEF <a>
+  # b = V_MAY_DEF <b>
   *p = 5;
 
   # VUSE <a>
@@ -740,21 +749,21 @@ operands, use the @option{-vops} option to @option{-fdump-tree}:
 @}
 @end smallexample
 
-Notice that @code{VDEF} operands have two copies of the referenced
+Notice that @code{V_MAY_DEF} operands have two copies of the referenced
 variable.  This indicates that this is not a killing definition of
 that variable.  In this case we refer to it as a @dfn{may definition}
 or @dfn{aliased store}.  The presence of the second copy of the
-variable in the @code{VDEF} operand will become important when the
+variable in the @code{V_MAY_DEF} operand will become important when the
 function is converted into SSA form.  This will be used to link all
 the non-killing definitions to prevent optimizations from making
 incorrect assumptions about them.
 
 Operands are collected by @file{tree-ssa-operands.c}.  They are stored
 inside each statement's annotation and can be accessed with
-@code{DEF_OPS}, @code{USE_OPS}, @code{VDEF_OPS} and @code{VUSE_OPS}.
-The following are all the accessor macros available to access USE
-operands.  To access all the other operand arrays, just change the
-name accordingly:
+@code{DEF_OPS}, @code{USE_OPS}, @code{V_MAY_DEF_OPS}, 
+@code{V_MUST_DEF_OPS} and @code{VUSE_OPS}. The following are all the 
+accessor macros available to access USE operands.  To access all the 
+other operand arrays, just change the name accordingly:
 
 @defmac USE_OPS (@var{ann})
 Returns the array of operands used by the statement with annotation
@@ -786,7 +795,8 @@ void
 print_ops (tree stmt)
 @{
   vuse_optype vuses;
-  vdef_optype vdefs;
+  v_may_def_optype v_may_defs;
+  v_must_def_optype v_must_defs;
   def_optype defs;
   use_optype uses;
   stmt_ann_t ann;
@@ -803,9 +813,13 @@ print_ops (tree stmt)
   for (i = 0; i < NUM_USES (uses); i++)
     print_generic_expr (stderr, USE_OP (uses, i), 0);
   
-  vdefs = VDEF_OPS (ann);
-  for (i = 0; i < NUM_VDEFS (vdefs); i++)
-    print_generic_expr (stderr, VDEF_OP (vdefs, i), 0);
+  v_may_defs = V_MAY_DEF_OPS (ann);
+  for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
+    print_generic_expr (stderr, V_MAY_DEF_OP (v_may_defs, i), 0);
+
+  v_must_defs = V_MUST_DEF_OPS (ann);
+  for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++)
+    print_generic_expr (stderr, V_MUST_DEF_OP (v_must_defs, i), 0);
   
   vuses = VUSE_OPS (ann);
   for (i = 0; i < NUM_VUSES (vuses); i++)
@@ -1095,11 +1109,11 @@ foo (int i)
     p_6 = &b;
   # p_1 = PHI <p_4(1), p_6(2)>;
 
-  # a_7 = VDEF <a_3>;
-  # b_8 = VDEF <b_5>;
+  # a_7 = V_MAY_DEF <a_3>;
+  # b_8 = V_MAY_DEF <b_5>;
   *p_1 = 3;
 
-  # a_9 = VDEF <a_7>
+  # a_9 = V_MAY_DEF <a_7>
   # VUSE <b_8>
   a_9 = b_8 + 2;