This patch fixes ICE:
https://godbolt.org/z/z8T6o6qov
<source>: In function 'b':
<source>:2:6: error: missing definition
2 | void b() {
| ^
for SSA_NAME: loop_len_8 in statement:
_1 = -loop_len_8;
during GIMPLE pass: vect
<source>:2:6: internal compiler error: verify_ssa failed
0x7f1b56331082 __libc_start_main
???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 1
The root cause is we generate such IR in vectorization:
_1 = -loop_len_8;
vect_cst__11 = {_1, _1};
_18 = vect_vec_iv_.6_14 + vect_cst__11;
loop_len_8 is uninitialized value.
The IR _18 = vect_vec_iv_.6_14 + vect_cst__11; is generated because of we are
adding induction variable with
the result of SELECT_VL instead of VF.
The code is:
else if (LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo))
{
/* When we're using loop_len produced by SELEC_VL, the non-final
iterations are not always processing VF elements. So vectorize
induction variable instead of
_21 = vect_vec_iv_.6_22 + { VF, ... };
We should generate:
_35 = .SELECT_VL (ivtmp_33, VF);
vect_cst__22 = [vec_duplicate_expr] _35;
_21 = vect_vec_iv_.6_22 + vect_cst__22; */
gcc_assert (!slp_node);
gimple_seq seq = NULL;
vec_loop_lens *lens = &LOOP_VINFO_LENS (loop_vinfo);
tree len = vect_get_loop_len (loop_vinfo, NULL, lens, 1, vectype, 0, 0);
expr = force_gimple_operand (fold_convert (TREE_TYPE (step_expr),
unshare_expr (len)),
&seq, true, NULL_TREE);
new_name = gimple_build (&seq, MULT_EXPR, TREE_TYPE (step_expr), expr,
step_expr);
gsi_insert_seq_before (&si, seq, GSI_SAME_STMT);
step_iv_si = &si;
}
LOOP_VINFO_USING_SELECT_VL_P is set before loop vectorization analysis so we
don't know whether it is partial
vectorization or not but the induction variable depends on SELECT_VL_P is true.
So update SELECT_VL_P as false when it is not partial vectorization.
PR middle-end/112554
gcc/ChangeLog:
* tree-vect-loop.cc (vect_determine_partial_vectors_and_peeling): Clear
SELECT_VL_P for non-partial vectorization.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/rvv/autovec/pr112554.c: New test.
---
.../gcc.target/riscv/rvv/autovec/pr112554.c | 12 ++++++++++++
gcc/tree-vect-loop.cc | 13 +++++++++++++
2 files changed, 25 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112554.c
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112554.c
b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112554.c
new file mode 100644
index 00000000000..4afa7c2b15c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112554.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv -mabi=lp64d -O3
--param=riscv-autovec-preference=fixed-vlmax" } */
+
+int a;
+void b() {
+ unsigned long c = 18446744073709551612UL;
+d:
+ --c;
+ a ^= c;
+ if (c)
+ goto d;
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index fb8d999ee6b..3f59139cb01 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -2657,6 +2657,19 @@ vect_determine_partial_vectors_and_peeling
(loop_vec_info loop_vinfo)
= (!LOOP_VINFO_USING_PARTIAL_VECTORS_P (loop_vinfo)
&& need_peeling_or_partial_vectors_p);
+ /* We set LOOP_VINFO_USING_SELECT_VL_P as true before loop vectorization
+ analysis that we don't know whether the loop is vectorized by partial
+ vectors (More details see tree-vect-loop-manip.cc).
+
+ However, SELECT_VL vectorizaton style should only applied on partial
+ vectorization since SELECT_VL is the GIMPLE IR that calculates the
+ number of elements to be process for each iteration.
+
+ After loop vectorization analysis, Clear LOOP_VINFO_USING_SELECT_VL_P
+ if it is not partial vectorized loop. */
+ if (!LOOP_VINFO_USING_PARTIAL_VECTORS_P (loop_vinfo))
+ LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo) = false;
+
return opt_result::success ();
}
--
2.36.3
