[PATCH V2] VECT: Fix ICE of variable stride on strieded load/store with SELECT_VL loop control.

[juzhe . zhong]

From: Ju-Zhe Zhong <juzhe.zh...@rivai.ai>

Hi, Richi.

Sorry for making mistake on LEN_MASK_GATHER_LOAD/LEN_MASK_SCATTER_STORE
with SELECT_VL loop control.

Consider this following case:
#define TEST_LOOP(DATA_TYPE, BITS)                                             \
  void __attribute__ ((noinline, noclone))                                     \
  f_##DATA_TYPE##_##BITS (DATA_TYPE *restrict dest, DATA_TYPE *restrict src,   \
                          INDEX##BITS stride, INDEX##BITS n)                   \
  {                                                                            \
    for (INDEX##BITS i = 0; i < n; ++i)                                        \
      dest[i] += src[i * stride];                                              \
  }

When "stride" is a constant, current flow works fine.
However, when "stride" is a variable. It causes an ICE:
# vectp_src.67_85 = PHI <vectp_src.67_86(6), src_21(D)(12)>
...
_96 = .SELECT_VL (ivtmp_94, 4);
...
ivtmp_78 = ((sizetype) _39 * (sizetype) _96) * 4;
vect__11.69_87 = .LEN_MASK_GATHER_LOAD (vectp_src.67_85, _84, 4, { 0, 0, 0, 0 
}, { -1, -1, -1, -1 }, _96, 0);
...
vectp_src.67_86 = vectp_src.67_85 + ivtmp_78;

Becase the IR: ivtmp_78 = ((sizetype) _39 * (sizetype) _96) * 4;

Instead, I split the IR into:

step_stride = _39
step = step_stride * 4
ivtmp_78 = step * _96

Thanks.

gcc/ChangeLog:

        * tree-vect-stmts.cc (vect_get_strided_load_store_ops): Fix ICE.

---
 gcc/tree-vect-stmts.cc | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index c10a4be60eb..10e71178ce7 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -3176,10 +3176,8 @@ vect_get_strided_load_store_ops (stmt_vec_info stmt_info,
        = fold_build2 (MULT_EXPR, sizetype,
                       fold_convert (sizetype, unshare_expr (DR_STEP (dr))),
                       loop_len);
-      tree bump = make_temp_ssa_name (sizetype, NULL, "ivtmp");
-      gassign *assign = gimple_build_assign (bump, tmp);
-      gsi_insert_before (gsi, assign, GSI_SAME_STMT);
-      *dataref_bump = bump;
+      *dataref_bump = force_gimple_operand_gsi (gsi, tmp, true, NULL_TREE, 
true,
+                                               GSI_SAME_STMT);
     }
   else
     {
-- 
2.36.3