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authorwschmidt <wschmidt@138bc75d-0d04-0410-961f-82ee72b054a4>2017-12-14 20:40:21 +0000
committerwschmidt <wschmidt@138bc75d-0d04-0410-961f-82ee72b054a4>2017-12-14 20:40:21 +0000
commit9272d891314824bdd8d2ec8c67d6713bbe868275 (patch)
treebb013d21a9c288daf2b7432bb527993bc1633078
parentd79872a83f33f1560e47278bcf8e78a3779e036c (diff)
downloadgcc-9272d891314824bdd8d2ec8c67d6713bbe868275.tar.gz
2017-12-14 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
* gimple-ssa-strength-reduction.c (analyze_increments): Distinguish replacement costs for constant strides from those for unknown strides. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@255664 138bc75d-0d04-0410-961f-82ee72b054a4
-rw-r--r--gcc/ChangeLog6
-rw-r--r--gcc/gimple-ssa-strength-reduction.c12
2 files changed, 17 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d20a1b4e3ef..2e079fa4b60 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-12-14 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
+
+ * gimple-ssa-strength-reduction.c (analyze_increments):
+ Distinguish replacement costs for constant strides from those for
+ unknown strides.
+
2017-12-14 Jakub Jelinek <jakub@redhat.com>
* var-tracking.c (variable_tracking_main_1): Formatting fix.
diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c
index b51239b94d0..0f90232cca3 100644
--- a/gcc/gimple-ssa-strength-reduction.c
+++ b/gcc/gimple-ssa-strength-reduction.c
@@ -3083,7 +3083,17 @@ analyze_increments (slsr_cand_t first_dep, machine_mode mode, bool speed)
else if (first_dep->kind == CAND_MULT)
{
int cost = mult_by_coeff_cost (incr, mode, speed);
- int repl_savings = mul_cost (speed, mode) - add_cost (speed, mode);
+ int repl_savings;
+
+ if (tree_fits_shwi_p (first_dep->stride))
+ {
+ HOST_WIDE_INT hwi_stride = tree_to_shwi (first_dep->stride);
+ repl_savings = mult_by_coeff_cost (hwi_stride, mode, speed);
+ }
+ else
+ repl_savings = mul_cost (speed, mode);
+ repl_savings -= add_cost (speed, mode);
+
if (speed)
cost = lowest_cost_path (cost, repl_savings, first_dep,
incr_vec[i].incr, COUNT_PHIS);