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authorRichard Biener <rguenther@suse.de>2017-12-14 14:32:24 +0000
committerRichard Biener <rguenth@gcc.gnu.org>2017-12-14 14:32:24 +0000
commit8fa06648cde628f49ac69587d31841fc338ec841 (patch)
tree4ed9aa324a460c80fca144994aeda6284b57d5b2
parentf297ebafdcdf5d5a8c3ef74c9906de67998e5aa7 (diff)
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re PR tree-optimization/83326 (SPEC CPU2017 648.exchange2_s ~6% performance regression with r255267 (reproducer attached))
2017-12-14 Richard Biener <rguenther@suse.de> PR tree-optimization/83326 * tree-ssa-loop-ivcanon.c (try_unroll_loop_completely): Add may_be_zero parameter and handle it by not marking the first peeled copy as not exiting the loop. (try_peel_loop): Likewise. (canonicalize_loop_induction_variables): Use number_of_iterations_exit to handle the case of constant or zero iterations and perform loop header copying on-the-fly. * gcc.dg/tree-ssa/pr81388-2.c: Adjust. From-SVN: r255635
-rw-r--r--gcc/ChangeLog11
-rw-r--r--gcc/testsuite/ChangeLog5
-rw-r--r--gcc/testsuite/gcc.dg/tree-ssa/pr81388-2.c2
-rw-r--r--gcc/tree-ssa-loop-ivcanon.c54
4 files changed, 64 insertions, 8 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d182308..4f97ca2 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,16 @@
2017-12-14 Richard Biener <rguenther@suse.de>
+ PR tree-optimization/83326
+ * tree-ssa-loop-ivcanon.c (try_unroll_loop_completely): Add
+ may_be_zero parameter and handle it by not marking the first
+ peeled copy as not exiting the loop.
+ (try_peel_loop): Likewise.
+ (canonicalize_loop_induction_variables): Use number_of_iterations_exit
+ to handle the case of constant or zero iterations and perform
+ loop header copying on-the-fly.
+
+2017-12-14 Richard Biener <rguenther@suse.de>
+
PR tree-optimization/83418
* vr-values.c (vr_values::extract_range_for_var_from_comparison_expr):
Instead of asserting we don't get unfolded comparisons deal with
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a7686ce..9bd5cbb 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-12-14 Richard Biener <rguenther@suse.de>
+
+ PR tree-optimization/83326
+ * gcc.dg/tree-ssa/pr81388-2.c: Adjust.
+
2017-12-14 Eric Botcazou <ebotcazou@adacore.com>
* gnat.dg/alignment11.adb: New test.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr81388-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr81388-2.c
index 71fd289..aa40588 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr81388-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr81388-2.c
@@ -11,4 +11,4 @@ void foo(unsigned dst)
} while (dst < end);
}
-/* { dg-final { scan-tree-dump-times " zero if " 1 "ivcanon" } } */
+/* { dg-final { scan-tree-dump " zero if " "ivcanon" } } */
diff --git a/gcc/tree-ssa-loop-ivcanon.c b/gcc/tree-ssa-loop-ivcanon.c
index ae66ace..ce5a833 100644
--- a/gcc/tree-ssa-loop-ivcanon.c
+++ b/gcc/tree-ssa-loop-ivcanon.c
@@ -681,7 +681,7 @@ unloop_loops (bitmap loop_closed_ssa_invalidated,
static bool
try_unroll_loop_completely (struct loop *loop,
- edge exit, tree niter,
+ edge exit, tree niter, bool may_be_zero,
enum unroll_level ul,
HOST_WIDE_INT maxiter,
location_t locus, bool allow_peel)
@@ -893,6 +893,8 @@ try_unroll_loop_completely (struct loop *loop,
exit = NULL;
bitmap_clear (wont_exit);
}
+ if (may_be_zero)
+ bitmap_clear_bit (wont_exit, 1);
if (!gimple_duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
n_unroll, wont_exit,
@@ -977,7 +979,7 @@ estimated_peeled_sequence_size (struct loop_size *size,
static bool
try_peel_loop (struct loop *loop,
- edge exit, tree niter,
+ edge exit, tree niter, bool may_be_zero,
HOST_WIDE_INT maxiter)
{
HOST_WIDE_INT npeel;
@@ -1080,6 +1082,8 @@ try_peel_loop (struct loop *loop,
exit = NULL;
bitmap_clear (wont_exit);
}
+ if (may_be_zero)
+ bitmap_clear_bit (wont_exit, 1);
if (!gimple_duplicate_loop_to_header_edge (loop, loop_preheader_edge (loop),
npeel, wont_exit,
exit, &edges_to_remove,
@@ -1152,13 +1156,35 @@ canonicalize_loop_induction_variables (struct loop *loop,
HOST_WIDE_INT maxiter;
bool modified = false;
location_t locus = UNKNOWN_LOCATION;
+ struct tree_niter_desc niter_desc;
+ bool may_be_zero = false;
- niter = number_of_latch_executions (loop);
+ /* For unrolling allow conditional constant or zero iterations, thus
+ perform loop-header copying on-the-fly. */
exit = single_exit (loop);
+ niter = chrec_dont_know;
+ if (exit && number_of_iterations_exit (loop, exit, &niter_desc, false))
+ {
+ niter = niter_desc.niter;
+ may_be_zero
+ = niter_desc.may_be_zero && !integer_zerop (niter_desc.may_be_zero);
+ }
if (TREE_CODE (niter) == INTEGER_CST)
locus = gimple_location (last_stmt (exit->src));
else
{
+ /* For non-constant niter fold may_be_zero into niter again. */
+ if (may_be_zero)
+ {
+ if (COMPARISON_CLASS_P (niter_desc.may_be_zero))
+ niter = fold_build3 (COND_EXPR, TREE_TYPE (niter),
+ niter_desc.may_be_zero,
+ build_int_cst (TREE_TYPE (niter), 0), niter);
+ else
+ niter = chrec_dont_know;
+ may_be_zero = false;
+ }
+
/* If the loop has more than one exit, try checking all of them
for # of iterations determinable through scev. */
if (!exit)
@@ -1213,17 +1239,31 @@ canonicalize_loop_induction_variables (struct loop *loop,
populates the loop bounds. */
modified |= remove_redundant_iv_tests (loop);
- if (try_unroll_loop_completely (loop, exit, niter, ul, maxiter, locus,
- allow_peel))
+ if (try_unroll_loop_completely (loop, exit, niter, may_be_zero, ul,
+ maxiter, locus, allow_peel))
return true;
if (create_iv
&& niter && !chrec_contains_undetermined (niter)
&& exit && just_once_each_iteration_p (loop, exit->src))
- create_canonical_iv (loop, exit, niter);
+ {
+ tree iv_niter = niter;
+ if (may_be_zero)
+ {
+ if (COMPARISON_CLASS_P (niter_desc.may_be_zero))
+ iv_niter = fold_build3 (COND_EXPR, TREE_TYPE (iv_niter),
+ niter_desc.may_be_zero,
+ build_int_cst (TREE_TYPE (iv_niter), 0),
+ iv_niter);
+ else
+ iv_niter = NULL_TREE;
+ }
+ if (iv_niter)
+ create_canonical_iv (loop, exit, iv_niter);
+ }
if (ul == UL_ALL)
- modified |= try_peel_loop (loop, exit, niter, maxiter);
+ modified |= try_peel_loop (loop, exit, niter, may_be_zero, maxiter);
return modified;
}