[gcc r13-5644] Don't peel nonlinear iv(mult or shift) for epilog when vf is not constant.
hongtao Liu
liuhongt@gcc.gnu.org
Thu Feb 2 09:02:58 GMT 2023
https://gcc.gnu.org/g:209f02b0a9e9adc0bf0247cb5eef04e0f175d64e
commit r13-5644-g209f02b0a9e9adc0bf0247cb5eef04e0f175d64e
Author: liuhongt <hongtao.liu@intel.com>
Date: Wed Feb 1 13:30:12 2023 +0800
Don't peel nonlinear iv(mult or shift) for epilog when vf is not constant.
Normally when vf is not constant, it will be prevented by
vectorizable_nonlinear_inductions, but for this case, it failed going
into
if (STMT_VINFO_RELEVANT_P (stmt_info))
{
need_to_vectorize = true;
if (STMT_VINFO_DEF_TYPE (stmt_info) == vect_induction_def
&& ! PURE_SLP_STMT (stmt_info))
ok = vectorizable_induction (loop_vinfo,
stmt_info, NULL, NULL,
&cost_vec);
since the iv is never used outside of the loop, and will be dce later, so
vectorizer doesn't bother checking if it's vectorizable. it's
true but hit gcc_assert in vect_can_peel_nonlinear_iv_p when vf is not
constant. One solution is ignoring the nonlinear iv peeling if it's
!STMT_VINFO_RELEVANT_P (stmt_info) just like the upper code, the other
solution is returning false earlier in the
vect_can_peel_nonlinear_iv_p when vf is not constant, the patch chooses
the second incase there's other cases using vect_can_advance_ivs_p which
calls vect_can_peel_nonlinear_iv_p.
Also remove vect_peel_nonlinear_iv_p from
vectorizable_nonlinear_inductions.
gcc/ChangeLog:
PR tree-optimization/108601
* tree-vectorizer.h (vect_can_peel_nonlinear_iv_p): Removed.
* tree-vect-loop.cc
(vectorizable_nonlinear_induction): Remove
vect_can_peel_nonlinear_iv_p.
(vect_can_peel_nonlinear_iv_p): Don't peel
nonlinear iv(mult or shift) for epilog when vf is not
constant and moved the defination to ..
* tree-vect-loop-manip.cc (vect_can_peel_nonlinear_iv_p):
.. Here.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/pr108601.c: New test.
Diff:
---
gcc/testsuite/gcc.target/aarch64/pr108601.c | 11 +++++++
gcc/tree-vect-loop-manip.cc | 44 +++++++++++++++++++++++++++
gcc/tree-vect-loop.cc | 46 -----------------------------
gcc/tree-vectorizer.h | 3 --
4 files changed, 55 insertions(+), 49 deletions(-)
diff --git a/gcc/testsuite/gcc.target/aarch64/pr108601.c b/gcc/testsuite/gcc.target/aarch64/pr108601.c
new file mode 100644
index 00000000000..deb8b3061d8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr108601.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fprofile-generate -mcpu=neoverse-v1" } */
+
+int
+foo() {
+ int flag = 1;
+ for (; flag <= 1 << 21; flag <<= 1)
+ ;
+ return 0;
+}
+
diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index b5c5f859144..c04fcf40c44 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -1390,6 +1390,50 @@ iv_phi_p (stmt_vec_info stmt_info)
return true;
}
+/* Return true if vectorizer can peel for nonlinear iv. */
+static bool
+vect_can_peel_nonlinear_iv_p (loop_vec_info loop_vinfo,
+ enum vect_induction_op_type induction_type)
+{
+ tree niters_skip;
+ /* Init_expr will be update by vect_update_ivs_after_vectorizer,
+ if niters or vf is unkown:
+ For shift, when shift mount >= precision, there would be UD.
+ For mult, don't known how to generate
+ init_expr * pow (step, niters) for variable niters.
+ For neg, it should be ok, since niters of vectorized main loop
+ will always be multiple of 2. */
+ if ((!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
+ || !LOOP_VINFO_VECT_FACTOR (loop_vinfo).is_constant ())
+ && induction_type != vect_step_op_neg)
+ {
+ if (dump_enabled_p ())
+ dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+ "Peeling for epilogue is not supported"
+ " for nonlinear induction except neg"
+ " when iteration count is unknown.\n");
+ return false;
+ }
+
+ /* Also doens't support peel for neg when niter is variable.
+ ??? generate something like niter_expr & 1 ? init_expr : -init_expr? */
+ niters_skip = LOOP_VINFO_MASK_SKIP_NITERS (loop_vinfo);
+ if ((niters_skip != NULL_TREE
+ && TREE_CODE (niters_skip) != INTEGER_CST)
+ || (!vect_use_loop_mask_for_alignment_p (loop_vinfo)
+ && LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo) < 0))
+ {
+ if (dump_enabled_p ())
+ dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+ "Peeling for alignement is not supported"
+ " for nonlinear induction when niters_skip"
+ " is not constant.\n");
+ return false;
+ }
+
+ return true;
+}
+
/* Function vect_can_advance_ivs_p
In case the number of iterations that LOOP iterates is unknown at compile
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index f03af1efd0f..becf96bb2b8 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -8812,49 +8812,6 @@ vect_update_nonlinear_iv (gimple_seq* stmts, tree vectype,
}
-/* Return true if vectorizer can peel for nonlinear iv. */
-bool
-vect_can_peel_nonlinear_iv_p (loop_vec_info loop_vinfo,
- enum vect_induction_op_type induction_type)
-{
- tree niters_skip;
- /* Init_expr will be update by vect_update_ivs_after_vectorizer,
- if niters is unkown:
- For shift, when shift mount >= precision, there would be UD.
- For mult, don't known how to generate
- init_expr * pow (step, niters) for variable niters.
- For neg, it should be ok, since niters of vectorized main loop
- will always be multiple of 2. */
- if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
- && induction_type != vect_step_op_neg)
- {
- if (dump_enabled_p ())
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
- "Peeling for epilogue is not supported"
- " for nonlinear induction except neg"
- " when iteration count is unknown.\n");
- return false;
- }
-
- /* Also doens't support peel for neg when niter is variable.
- ??? generate something like niter_expr & 1 ? init_expr : -init_expr? */
- niters_skip = LOOP_VINFO_MASK_SKIP_NITERS (loop_vinfo);
- if ((niters_skip != NULL_TREE
- && TREE_CODE (niters_skip) != INTEGER_CST)
- || (!vect_use_loop_mask_for_alignment_p (loop_vinfo)
- && LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo) < 0))
- {
- if (dump_enabled_p ())
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
- "Peeling for alignement is not supported"
- " for nonlinear induction when niters_skip"
- " is not constant.\n");
- return false;
- }
-
- return true;
-}
-
/* Function vectorizable_induction
Check if STMT_INFO performs an nonlinear induction computation that can be
@@ -8925,9 +8882,6 @@ vectorizable_nonlinear_induction (loop_vec_info loop_vinfo,
return false;
}
- if (!vect_can_peel_nonlinear_iv_p (loop_vinfo, induction_type))
- return false;
-
if (!INTEGRAL_TYPE_P (TREE_TYPE (vectype)))
{
if (dump_enabled_p ())
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index a2aa71bedc0..4ba653712e9 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -2347,9 +2347,6 @@ extern tree cse_and_gimplify_to_preheader (loop_vec_info, tree);
/* Nonlinear induction. */
extern tree vect_peel_nonlinear_iv_init (gimple_seq*, tree, tree,
tree, enum vect_induction_op_type);
-extern bool
-vect_can_peel_nonlinear_iv_p (loop_vec_info loop_vinfo,
- enum vect_induction_op_type induction_type);
/* In tree-vect-slp.cc. */
extern void vect_slp_init (void);
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