The following applies manual tail-recusion transform to add chains
SLP generates.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2019-08-19 Richard Biener <rguent...@suse.de>
PR tree-optimization/91403
* tree-scalar-evolution.c (follow_ssa_edge_binary): Inline
cases we can handle with tail-recursion...
(follow_ssa_edge_expr): ... here. Do so.
Index: gcc/tree-scalar-evolution.c
===================================================================
--- gcc/tree-scalar-evolution.c (revision 274666)
+++ gcc/tree-scalar-evolution.c (working copy)
@@ -925,32 +925,11 @@ follow_ssa_edge_binary (class loop *loop
res = follow_ssa_edge_expr
(loop, at_stmt, rhs1, halting_phi,
evolution_of_loop, limit);
- if (res == t_true)
- ;
- else if (res == t_dont_know)
- *evolution_of_loop = chrec_dont_know;
}
-
- else if (res == t_dont_know)
- *evolution_of_loop = chrec_dont_know;
}
else
- {
- /* Match an assignment under the form:
- "a = b + ...". */
- *evolution_of_loop = add_to_evolution
- (loop->num, chrec_convert (type, *evolution_of_loop,
- at_stmt),
- code, rhs1, at_stmt);
- res = follow_ssa_edge_expr
- (loop, at_stmt, rhs0, halting_phi,
- evolution_of_loop, limit);
- if (res == t_true)
- ;
- else if (res == t_dont_know)
- *evolution_of_loop = chrec_dont_know;
- }
+ gcc_unreachable (); /* Handled in caller. */
}
else if (TREE_CODE (rhs1) == SSA_NAME)
@@ -964,10 +943,6 @@ follow_ssa_edge_binary (class loop *loop
res = follow_ssa_edge_expr
(loop, at_stmt, rhs1, halting_phi,
evolution_of_loop, limit);
- if (res == t_true)
- ;
- else if (res == t_dont_know)
- *evolution_of_loop = chrec_dont_know;
}
else
@@ -980,26 +955,7 @@ follow_ssa_edge_binary (class loop *loop
case MINUS_EXPR:
/* This case is under the form "opnd0 = rhs0 - rhs1". */
if (TREE_CODE (rhs0) == SSA_NAME)
- {
- /* Match an assignment under the form:
- "a = b - ...". */
-
- /* We want only assignments of form "name - name" contribute to
- LIMIT, as the other cases do not necessarily contribute to
- the complexity of the expression. */
- if (TREE_CODE (rhs1) == SSA_NAME)
- limit++;
-
- *evolution_of_loop = add_to_evolution
- (loop->num, chrec_convert (type, *evolution_of_loop, at_stmt),
- MINUS_EXPR, rhs1, at_stmt);
- res = follow_ssa_edge_expr (loop, at_stmt, rhs0, halting_phi,
- evolution_of_loop, limit);
- if (res == t_true)
- ;
- else if (res == t_dont_know)
- *evolution_of_loop = chrec_dont_know;
- }
+ gcc_unreachable (); /* Handled in caller. */
else
/* Otherwise, match an assignment under the form:
"a = ... - ...". */
@@ -1184,6 +1140,7 @@ follow_ssa_edge_expr (class loop *loop,
/* For SSA_NAME look at the definition statement, handling
PHI nodes and otherwise expand appropriately for the expression
handling below. */
+tail_recurse:
if (TREE_CODE (expr) == SSA_NAME)
{
gimple *def = SSA_NAME_DEF_STMT (expr);
@@ -1193,7 +1150,10 @@ follow_ssa_edge_expr (class loop *loop,
/* Give up if the path is longer than the MAX that we allow. */
if (limit > PARAM_VALUE (PARAM_SCEV_MAX_EXPR_COMPLEXITY))
- return t_dont_know;
+ {
+ *evolution_of_loop = chrec_dont_know;
+ return t_dont_know;
+ }
if (gphi *phi = dyn_cast <gphi *>(def))
{
@@ -1303,14 +1263,28 @@ follow_ssa_edge_expr (class loop *loop,
/* This case is under the form "rhs0 +- rhs1". */
STRIP_USELESS_TYPE_CONVERSION (rhs0);
STRIP_USELESS_TYPE_CONVERSION (rhs1);
+ if (TREE_CODE (rhs0) == SSA_NAME
+ && (TREE_CODE (rhs1) != SSA_NAME || code == MINUS_EXPR))
+ {
+ /* Match an assignment under the form:
+ "a = b +- ...".
+ Use tail-recursion for the simple case. */
+ *evolution_of_loop = add_to_evolution
+ (loop->num, chrec_convert (type, *evolution_of_loop,
+ at_stmt),
+ code, rhs1, at_stmt);
+ expr = rhs0;
+ goto tail_recurse;
+ }
+ /* Else search for the SCC in both rhs0 and rhs1. */
return follow_ssa_edge_binary (loop, at_stmt, type, rhs0, code, rhs1,
halting_phi, evolution_of_loop, limit);
case ASSERT_EXPR:
/* This assignment is of the form: "a_1 = ASSERT_EXPR <a_2, ...>"
It must be handled as a copy assignment of the form a_1 = a_2. */
- return follow_ssa_edge_expr (loop, at_stmt, ASSERT_EXPR_VAR (rhs0),
- halting_phi, evolution_of_loop, limit);
+ expr = ASSERT_EXPR_VAR (rhs0);
+ goto tail_recurse;
default:
return t_false;
