[PATCH, committed] Backport PR87473 fix to GCC 8
Bill Schmidt
wschmidt@linux.ibm.com
Fri Oct 26 21:34:00 GMT 2018
Committed the backport as follows:
[gcc]
2018-10-26 Bill Schmidt <wschmidt@linux.ibm.com>
Backport from mainline
2018-10-19 Bill Schmidt <wschmidt@linux.ibm.com>
PR tree-optimization/87473
* gimple-ssa-strength-reduction.c (record_phi_increments_1): For
phi arguments identical to the base expression of the phi
candidate, record a phi-adjust increment of zero minus the index
expression of the hidden basis.
(phi_incr_cost_1): For phi arguments identical to the base
expression of the phi candidate, the difference to compare against
the increment is zero minus the index expression of the hidden
basis, and there is no potential savings from replacing the (phi)
statement.
(ncd_with_phi): For phi arguments identical to the base expression
of the phi candidate, the difference to compare against the
increment is zero minus the index expression of the hidden basis.
(all_phi_incrs_profitable_1): For phi arguments identical to the
base expression of the phi candidate, the increment to be checked
for profitability is zero minus the index expression of the hidden
basis.
[gcc/testsuite]
2018-10-26 Bill Schmidt <wschmidt@linux.ibm.com>
Backport from mainline
2018-10-19 Bill Schmidt <wschmidt@linux.ibm.com>
PR tree-optimization/87473
* gcc.c-torture/compile/pr87473.c: New file.
Index: gcc/gimple-ssa-strength-reduction.c
===================================================================
--- gcc/gimple-ssa-strength-reduction.c (revision 265534)
+++ gcc/gimple-ssa-strength-reduction.c (working copy)
@@ -2779,17 +2779,23 @@ record_phi_increments_1 (slsr_cand_t basis, gimple
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
tree arg = gimple_phi_arg_def (phi, i);
+ gimple *arg_def = SSA_NAME_DEF_STMT (arg);
- if (!operand_equal_p (arg, phi_cand->base_expr, 0))
+ if (gimple_code (arg_def) == GIMPLE_PHI)
+ record_phi_increments_1 (basis, arg_def);
+ else
{
- gimple *arg_def = SSA_NAME_DEF_STMT (arg);
+ widest_int diff;
- if (gimple_code (arg_def) == GIMPLE_PHI)
- record_phi_increments_1 (basis, arg_def);
+ if (operand_equal_p (arg, phi_cand->base_expr, 0))
+ {
+ diff = -basis->index;
+ record_increment (phi_cand, diff, PHI_ADJUST);
+ }
else
{
slsr_cand_t arg_cand = base_cand_from_table (arg);
- widest_int diff = arg_cand->index - basis->index;
+ diff = arg_cand->index - basis->index;
record_increment (arg_cand, diff, PHI_ADJUST);
}
}
@@ -2864,29 +2870,43 @@ phi_incr_cost_1 (slsr_cand_t c, const widest_int &
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
tree arg = gimple_phi_arg_def (phi, i);
+ gimple *arg_def = SSA_NAME_DEF_STMT (arg);
- if (!operand_equal_p (arg, phi_cand->base_expr, 0))
+ if (gimple_code (arg_def) == GIMPLE_PHI)
{
- gimple *arg_def = SSA_NAME_DEF_STMT (arg);
-
- if (gimple_code (arg_def) == GIMPLE_PHI)
+ int feeding_savings = 0;
+ tree feeding_var = gimple_phi_result (arg_def);
+ cost += phi_incr_cost_1 (c, incr, arg_def, &feeding_savings);
+ if (uses_consumed_by_stmt (feeding_var, phi))
+ *savings += feeding_savings;
+ }
+ else
+ {
+ widest_int diff;
+ slsr_cand_t arg_cand;
+
+ /* When the PHI argument is just a pass-through to the base
+ expression of the hidden basis, the difference is zero minus
+ the index of the basis. There is no potential savings by
+ eliminating a statement in this case. */
+ if (operand_equal_p (arg, phi_cand->base_expr, 0))
{
- int feeding_savings = 0;
- tree feeding_var = gimple_phi_result (arg_def);
- cost += phi_incr_cost_1 (c, incr, arg_def, &feeding_savings);
- if (uses_consumed_by_stmt (feeding_var, phi))
- *savings += feeding_savings;
+ arg_cand = (slsr_cand_t)NULL;
+ diff = -basis->index;
}
else
{
- slsr_cand_t arg_cand = base_cand_from_table (arg);
- widest_int diff = arg_cand->index - basis->index;
-
- if (incr == diff)
+ arg_cand = base_cand_from_table (arg);
+ diff = arg_cand->index - basis->index;
+ }
+
+ if (incr == diff)
+ {
+ tree basis_lhs = gimple_assign_lhs (basis->cand_stmt);
+ cost += add_cost (true, TYPE_MODE (TREE_TYPE (basis_lhs)));
+ if (arg_cand)
{
- tree basis_lhs = gimple_assign_lhs (basis->cand_stmt);
tree lhs = gimple_assign_lhs (arg_cand->cand_stmt);
- cost += add_cost (true, TYPE_MODE (TREE_TYPE (basis_lhs)));
if (uses_consumed_by_stmt (lhs, phi))
*savings += stmt_cost (arg_cand->cand_stmt, true);
}
@@ -3228,23 +3248,26 @@ ncd_with_phi (slsr_cand_t c, const widest_int &inc
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
tree arg = gimple_phi_arg_def (phi, i);
+ gimple *arg_def = SSA_NAME_DEF_STMT (arg);
- if (!operand_equal_p (arg, phi_cand->base_expr, 0))
+ if (gimple_code (arg_def) == GIMPLE_PHI)
+ ncd = ncd_with_phi (c, incr, as_a <gphi *> (arg_def), ncd, where);
+ else
{
- gimple *arg_def = SSA_NAME_DEF_STMT (arg);
+ widest_int diff;
- if (gimple_code (arg_def) == GIMPLE_PHI)
- ncd = ncd_with_phi (c, incr, as_a <gphi *> (arg_def), ncd,
- where);
- else
+ if (operand_equal_p (arg, phi_cand->base_expr, 0))
+ diff = -basis->index;
+ else
{
slsr_cand_t arg_cand = base_cand_from_table (arg);
- widest_int diff = arg_cand->index - basis->index;
- basic_block pred = gimple_phi_arg_edge (phi, i)->src;
-
- if ((incr == diff) || (!address_arithmetic_p && incr == -diff))
- ncd = ncd_for_two_cands (ncd, pred, *where, NULL, where);
+ diff = arg_cand->index - basis->index;
}
+
+ basic_block pred = gimple_phi_arg_edge (phi, i)->src;
+
+ if ((incr == diff) || (!address_arithmetic_p && incr == -diff))
+ ncd = ncd_for_two_cands (ncd, pred, *where, NULL, where);
}
}
@@ -3515,51 +3538,53 @@ all_phi_incrs_profitable_1 (slsr_cand_t c, gphi *p
return false;
tree arg = gimple_phi_arg_def (phi, i);
+ gimple *arg_def = SSA_NAME_DEF_STMT (arg);
- if (!operand_equal_p (arg, phi_cand->base_expr, 0))
+ if (gimple_code (arg_def) == GIMPLE_PHI)
{
- gimple *arg_def = SSA_NAME_DEF_STMT (arg);
+ if (!all_phi_incrs_profitable_1 (c, as_a <gphi *> (arg_def), spread)
+ || *spread > MAX_SPREAD)
+ return false;
+ }
+ else
+ {
+ int j;
+ widest_int increment;
- if (gimple_code (arg_def) == GIMPLE_PHI)
- {
- if (!all_phi_incrs_profitable_1 (c, as_a <gphi *> (arg_def),
- spread)
- || *spread > MAX_SPREAD)
- return false;
- }
+ if (operand_equal_p (arg, phi_cand->base_expr, 0))
+ increment = -basis->index;
else
{
- int j;
slsr_cand_t arg_cand = base_cand_from_table (arg);
- widest_int increment = arg_cand->index - basis->index;
+ increment = arg_cand->index - basis->index;
+ }
- if (!address_arithmetic_p && wi::neg_p (increment))
- increment = -increment;
+ if (!address_arithmetic_p && wi::neg_p (increment))
+ increment = -increment;
- j = incr_vec_index (increment);
+ j = incr_vec_index (increment);
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, " Conditional candidate %d, phi: ",
- c->cand_num);
- print_gimple_stmt (dump_file, phi, 0);
- fputs (" increment: ", dump_file);
- print_decs (increment, dump_file);
- if (j < 0)
- fprintf (dump_file,
- "\n Not replaced; incr_vec overflow.\n");
- else {
- fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost);
- if (profitable_increment_p (j))
- fputs (" Replacing...\n", dump_file);
- else
- fputs (" Not replaced.\n", dump_file);
- }
- }
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, " Conditional candidate %d, phi: ",
+ c->cand_num);
+ print_gimple_stmt (dump_file, phi, 0);
+ fputs (" increment: ", dump_file);
+ print_decs (increment, dump_file);
+ if (j < 0)
+ fprintf (dump_file,
+ "\n Not replaced; incr_vec overflow.\n");
+ else {
+ fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost);
+ if (profitable_increment_p (j))
+ fputs (" Replacing...\n", dump_file);
+ else
+ fputs (" Not replaced.\n", dump_file);
+ }
+ }
- if (j < 0 || !profitable_increment_p (j))
- return false;
- }
+ if (j < 0 || !profitable_increment_p (j))
+ return false;
}
}
Index: gcc/testsuite/gcc.c-torture/compile/pr87473.c
===================================================================
--- gcc/testsuite/gcc.c-torture/compile/pr87473.c (nonexistent)
+++ gcc/testsuite/gcc.c-torture/compile/pr87473.c (working copy)
@@ -0,0 +1,19 @@
+/* PR87473: SLSR ICE on hidden basis with |increment| > 1. */
+/* { dg-additional-options "-fno-tree-ch" } */
+
+void
+t6 (int qz, int wh)
+{
+ int jl = wh;
+
+ while (1.0 / 0 < 1)
+ {
+ qz = wh * (wh + 2);
+
+ while (wh < 1)
+ jl = 0;
+ }
+
+ while (qz < 1)
+ qz = jl * wh;
+}
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