https://gcc.gnu.org/g:56670281c6db19d75c7b63e38971ab84681b245c
commit r15-1763-g56670281c6db19d75c7b63e38971ab84681b245c
Author: Kewen Lin <li...@linux.ibm.com>
Date: Tue Jul 2 02:13:35 2024 -0500
isel: Fold more in gimple_expand_vec_cond_expr [PR115659]
As PR115659 shows, assuming c = x CMP y, there are some
folding chances for patterns r = c ? -1/z : z/0.
For r = c ? -1 : z, it can be folded into:
- r = c | z (with ior_optab supported)
- or r = c ? c : z
while for r = c ? z : 0, it can be foled into:
- r = c & z (with and_optab supported)
- or r = c ? z : c
This patch is to teach ISEL to take care of them and also
remove the redundant gsi_replace as the caller of function
gimple_expand_vec_cond_expr will handle it.
PR tree-optimization/115659
gcc/ChangeLog:
* gimple-isel.cc (gimple_expand_vec_cond_expr): Add more foldings
for
patterns x CMP y ? -1 : z and x CMP y ? z : 0.
Diff:
---
gcc/gimple-isel.cc | 48 +++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 41 insertions(+), 7 deletions(-)
diff --git a/gcc/gimple-isel.cc b/gcc/gimple-isel.cc
index 54c1801038b..60719eafc65 100644
--- a/gcc/gimple-isel.cc
+++ b/gcc/gimple-isel.cc
@@ -240,16 +240,50 @@ gimple_expand_vec_cond_expr (struct function *fun,
gimple_stmt_iterator *gsi,
can_compute_op0 = expand_vec_cmp_expr_p (op0a_type, op0_type,
tcode);
- /* Try to fold x CMP y ? -1 : 0 to x CMP y. */
if (can_compute_op0
- && integer_minus_onep (op1)
- && integer_zerop (op2)
&& TYPE_MODE (TREE_TYPE (lhs)) == TYPE_MODE (TREE_TYPE (op0)))
{
- tree conv_op = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), op0);
- gassign *new_stmt = gimple_build_assign (lhs, conv_op);
- gsi_replace (gsi, new_stmt, true);
- return new_stmt;
+ /* Assuming c = x CMP y. */
+ bool op1_minus_onep = integer_minus_onep (op1);
+ bool op2_zerop = integer_zerop (op2);
+ tree vtype = TREE_TYPE (lhs);
+ machine_mode vmode = TYPE_MODE (vtype);
+ /* Try to fold r = c ? -1 : 0 to r = c. */
+ if (op1_minus_onep && op2_zerop)
+ {
+ tree conv_op = build1 (VIEW_CONVERT_EXPR, vtype, op0);
+ return gimple_build_assign (lhs, conv_op);
+ }
+ /* Try to fold r = c ? -1 : z to r = c | z, or
+ r = c ? c : z. */
+ if (op1_minus_onep)
+ {
+ tree conv_op = build1 (VIEW_CONVERT_EXPR, vtype, op0);
+ tree new_op1 = make_ssa_name (vtype);
+ gassign *new_stmt = gimple_build_assign (new_op1, conv_op);
+ gsi_insert_seq_before (gsi, new_stmt, GSI_SAME_STMT);
+ if (optab_handler (ior_optab, vmode) != CODE_FOR_nothing)
+ /* r = c | z */
+ return gimple_build_assign (lhs, BIT_IOR_EXPR, new_op1,
+ op2);
+ /* r = c ? c : z */
+ op1 = new_op1;
+ }
+ /* Try to fold r = c ? z : 0 to r = c & z, or
+ r = c ? z : c. */
+ else if (op2_zerop)
+ {
+ tree conv_op = build1 (VIEW_CONVERT_EXPR, vtype, op0);
+ tree new_op2 = make_ssa_name (vtype);
+ gassign *new_stmt = gimple_build_assign (new_op2, conv_op);
+ gsi_insert_seq_before (gsi, new_stmt, GSI_SAME_STMT);
+ if (optab_handler (and_optab, vmode) != CODE_FOR_nothing)
+ /* r = c | z */
+ return gimple_build_assign (lhs, BIT_AND_EXPR, new_op2,
+ op1);
+ /* r = c ? z : c */
+ op2 = new_op2;
+ }
}
/* When the compare has EH we do not want to forward it when
