On 8/11/24 3:00 PM, Robin Dapp wrote:
When predicating a load we implicitly assume that the else value is
zero. In order to formalize this this patch queries the target for
its supported else operand and uses that for the maskload call.
Subsequently, if the else operand is nonzero, a cond_expr enforcing
a zero else value is emitted.
gcc/ChangeLog:
* tree-if-conv.cc (predicate_load_or_store): Enforce zero else
value.
(predicate_statements): Use sequence instead of statement.
---
gcc/tree-if-conv.cc | 78 +++++++++++++++++++++++++++++++++++----------
1 file changed, 62 insertions(+), 16 deletions(-)
diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc
index 57992b6deca..54cb9ef0ef1 100644
--- a/gcc/tree-if-conv.cc
+++ b/gcc/tree-if-conv.cc
@@ -2452,10 +2452,12 @@ mask_exists (int size, const vec<int> &vec)
write and it needs to be predicated by MASK. Return a statement
that does so. */
-static gimple *
-predicate_load_or_store (gimple_stmt_iterator *gsi, gassign *stmt, tree mask)
+static gimple_seq
+predicate_load_or_store (gimple_stmt_iterator *gsi, gassign *stmt, tree mask,
+ hash_set<tree_ssa_name_hash> *ssa_names)
Need an update to the function comment for the new SSA_NAMES argument.
@@ -2789,11 +2829,17 @@ predicate_statements (loop_p loop)
vect_masks.safe_push (mask);
}
if (gimple_assign_single_p (stmt))
- new_stmt = predicate_load_or_store (&gsi, stmt, mask);
- else
- new_stmt = predicate_rhs_code (stmt, mask, cond, &ssa_names);
+ {
+ gimple_seq call_seq
+ = predicate_load_or_store (&gsi, stmt, mask, &ssa_names);
- gsi_replace (&gsi, new_stmt, true);
+ gsi_replace_with_seq (&gsi, call_seq, true);
+ }
+ else
+ {
+ new_stmt = predicate_rhs_code (stmt, mask, cond, &ssa_names);
+ gsi_replace (&gsi, new_stmt, true);
+ }
Consider moving NEW_STMT's declaration into the scope where it's only
set/use occur.
Overall it looks quite reasonable to me. OK with the nits fixed.
jeff
