Currently we scale the number of stmts allowed for forward
jump threading to limit those for backwards jump threading
by applying a factor of two to the counted stmts. That doesn't
allow fine-grained adjustments, like by a single stmt as needed
for PR109893. The following changes the factor to be a percentage
of the forward threading number.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Any opinion on whether I should change the param name when I change
its meaning?
* params.opt (fsm-scale-path-stmts): Change to percentage.
* doc/invoke.texi (--param fsm-scale-path-stmts): Adjust.
* tree-ssa-threadbackward.cc
(back_threader_profitability::possibly_profitable_path_p):
Adjust param_fsm_scale_path_stmts uses.
(back_threader_profitability::profitable_path_p): Likewise.
---
gcc/doc/invoke.texi | 4 ++--
gcc/params.opt | 4 ++--
gcc/tree-ssa-threadbackward.cc | 17 +++++++++--------
3 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 74f5ee26042..1a0a507dddc 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -17462,8 +17462,8 @@ Maximum number of arrays per scop.
Max. size of loc list for which reverse ops should be added.
@item fsm-scale-path-stmts
-Scale factor to apply to the number of statements in a threading path
-crossing a loop backedge when comparing to
+Percentage of max-jump-thread-duplication-stmts to allow for the number of
+statements in a threading path crossing a loop backedge.
@option{--param=max-jump-thread-duplication-stmts}.
@item uninit-control-dep-attempts
diff --git a/gcc/params.opt b/gcc/params.opt
index 31aa0bd5753..0a1dfb46dd1 100644
--- a/gcc/params.opt
+++ b/gcc/params.opt
@@ -143,8 +143,8 @@ Common Joined UInteger Var(param_file_cache_lines) Init(0)
Param
Max number of lines to index into file cache. When 0 this is automatically
sized.
-param=fsm-scale-path-stmts=
-Common Joined UInteger Var(param_fsm_scale_path_stmts) Init(2) IntegerRange(1,
10) Param Optimization
-Scale factor to apply to the number of statements in a threading path crossing
a loop backedge when comparing to max-jump-thread-duplication-stmts.
+Common Joined UInteger Var(param_fsm_scale_path_stmts) Init(50)
IntegerRange(1, 100) Param Optimization
+Percentage of max-jump-thread-duplication-stmts to allow for the number of
statements in a threading path crossing a loop backedge.
-param=fully-pipelined-fma=
Common Joined UInteger Var(param_fully_pipelined_fma) Init(0) IntegerRange(0,
1) Param Optimization
diff --git a/gcc/tree-ssa-threadbackward.cc b/gcc/tree-ssa-threadbackward.cc
index 3adb83e9712..ce765cb5ded 100644
--- a/gcc/tree-ssa-threadbackward.cc
+++ b/gcc/tree-ssa-threadbackward.cc
@@ -739,8 +739,8 @@ back_threader_profitability::possibly_profitable_path_p
if ((!m_threaded_multiway_branch
|| !loop->latch
|| loop->latch->index == EXIT_BLOCK)
- && (m_n_insns * param_fsm_scale_path_stmts
- >= param_max_jump_thread_duplication_stmts))
+ && (m_n_insns * 100 >= (param_max_jump_thread_duplication_stmts
+ * param_fsm_scale_path_stmts)))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
@@ -749,8 +749,9 @@ back_threader_profitability::possibly_profitable_path_p
return false;
}
*large_non_fsm = (!(m_threaded_through_latch && m_threaded_multiway_branch)
- && (m_n_insns * param_fsm_scale_path_stmts
- >= param_max_jump_thread_duplication_stmts));
+ && (m_n_insns * 100
+ >= (param_max_jump_thread_duplication_stmts
+ * param_fsm_scale_path_stmts)));
if (dump_file && (dump_flags & TDF_DETAILS))
fputc ('\n', dump_file);
@@ -823,8 +824,8 @@ back_threader_profitability::profitable_path_p (const
vec<basic_block> &m_path,
if (!m_threaded_multiway_branch
&& *creates_irreducible_loop
&& (!(cfun->curr_properties & PROP_loop_opts_done)
- || (m_n_insns * param_fsm_scale_path_stmts
- >= param_max_jump_thread_duplication_stmts)))
+ || (m_n_insns * 100 >= (param_max_jump_thread_duplication_stmts
+ * param_fsm_scale_path_stmts))))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
@@ -839,8 +840,8 @@ back_threader_profitability::profitable_path_p (const
vec<basic_block> &m_path,
case, drastically reduce the number of statements we are allowed
to copy. */
if (!(m_threaded_through_latch && m_threaded_multiway_branch)
- && (m_n_insns * param_fsm_scale_path_stmts
- >= param_max_jump_thread_duplication_stmts))
+ && (m_n_insns * 100 >= (param_max_jump_thread_duplication_stmts
+ * param_fsm_scale_path_stmts)))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
--
2.43.0
