tree-ssa-dom.c (simple_iv_increment_p): New function.
* tree-ssa-dom.c (simple_iv_increment_p): New function. (simplify_rhs_and_lookup_avail_expr, eliminate_redundant_computations): Do not propagate value of iv before increment over the increment. From-SVN: r95571
This commit is contained in:
parent
e0fa00d1f4
commit
f67e783f49
|
@ -1,3 +1,9 @@
|
|||
2005-02-26 Zdenek Dvorak <dvorakz@suse.cz>
|
||||
|
||||
* tree-ssa-dom.c (simple_iv_increment_p): New function.
|
||||
(simplify_rhs_and_lookup_avail_expr, eliminate_redundant_computations):
|
||||
Do not propagate value of iv before increment over the increment.
|
||||
|
||||
2005-02-25 Joseph S. Myers <joseph@codesourcery.com>
|
||||
|
||||
* c-parser.c: New file.
|
||||
|
@ -66,12 +72,6 @@
|
|||
* doc/extend.texi (5.24 Declaring Attributes of Functions)<noreturn>:
|
||||
Clarify that the alternative way doesn't work in GNU C++.
|
||||
|
||||
2005-02-25 Zdenek Dvorak <dvorakz@suse.cz>
|
||||
|
||||
* tree-ssa-dom.c (simple_iv_increment_p): New function.
|
||||
(simplify_rhs_and_lookup_avail_expr, eliminate_redundant_computations):
|
||||
Do not propagate value of iv before increment over the increment.
|
||||
|
||||
2005-02-25 Zdenek Dvorak <dvorakz@suse.cz>
|
||||
|
||||
PR tree-optimization/19937
|
||||
|
|
|
@ -1635,6 +1635,46 @@ unsafe_associative_fp_binop (tree exp)
|
|||
&& FLOAT_TYPE_P (TREE_TYPE (exp)));
|
||||
}
|
||||
|
||||
/* Returns true when STMT is a simple iv increment. It detects the
|
||||
following situation:
|
||||
|
||||
i_1 = phi (..., i_2)
|
||||
i_2 = i_1 +/- ... */
|
||||
|
||||
static bool
|
||||
simple_iv_increment_p (tree stmt)
|
||||
{
|
||||
tree lhs, rhs, preinc, phi;
|
||||
unsigned i;
|
||||
|
||||
if (TREE_CODE (stmt) != MODIFY_EXPR)
|
||||
return false;
|
||||
|
||||
lhs = TREE_OPERAND (stmt, 0);
|
||||
if (TREE_CODE (lhs) != SSA_NAME)
|
||||
return false;
|
||||
|
||||
rhs = TREE_OPERAND (stmt, 1);
|
||||
|
||||
if (TREE_CODE (rhs) != PLUS_EXPR
|
||||
&& TREE_CODE (rhs) != MINUS_EXPR)
|
||||
return false;
|
||||
|
||||
preinc = TREE_OPERAND (rhs, 0);
|
||||
if (TREE_CODE (preinc) != SSA_NAME)
|
||||
return false;
|
||||
|
||||
phi = SSA_NAME_DEF_STMT (preinc);
|
||||
if (TREE_CODE (phi) != PHI_NODE)
|
||||
return false;
|
||||
|
||||
for (i = 0; i < (unsigned) PHI_NUM_ARGS (phi); i++)
|
||||
if (PHI_ARG_DEF (phi, i) == lhs)
|
||||
return true;
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
/* STMT is a MODIFY_EXPR for which we were unable to find RHS in the
|
||||
hash tables. Try to simplify the RHS using whatever equivalences
|
||||
we may have recorded.
|
||||
|
@ -1688,6 +1728,11 @@ simplify_rhs_and_lookup_avail_expr (struct dom_walk_data *walk_data,
|
|||
{
|
||||
tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
|
||||
|
||||
/* If the statement defines an induction variable, do not propagate
|
||||
its value, so that we do not create overlapping life ranges. */
|
||||
if (simple_iv_increment_p (rhs_def_stmt))
|
||||
goto dont_fold_assoc;
|
||||
|
||||
/* See if the RHS_DEF_STMT has the same form as our statement. */
|
||||
if (TREE_CODE (rhs_def_stmt) == MODIFY_EXPR)
|
||||
{
|
||||
|
@ -2551,7 +2596,10 @@ eliminate_redundant_computations (struct dom_walk_data *walk_data,
|
|||
|| ! def
|
||||
|| TREE_CODE (def) != SSA_NAME
|
||||
|| SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def)
|
||||
|| NUM_V_MAY_DEFS (v_may_defs) != 0)
|
||||
|| NUM_V_MAY_DEFS (v_may_defs) != 0
|
||||
/* Do not record equivalences for increments of ivs. This would create
|
||||
overlapping live ranges for a very questionable gain. */
|
||||
|| simple_iv_increment_p (stmt))
|
||||
insert = false;
|
||||
|
||||
/* Check if the expression has been computed before. */
|
||||
|
|
Loading…
Reference in New Issue