Like the patch to phiopt (r15-4033-g1f619fe25925a5f7), this adds rewriting
of VCE to gimple_with_undefined_signed_overflow/rewrite_to_defined_overflow.
I have not seen a case yet for needing this rewrite but this step is needed
to use gimple_with_undefined_signed_overflow/rewrite_to_defined_overflow from
phiopt.
Bootstrappd and tested on x86_64-linux-gnu.
gcc/ChangeLog:
PR tree-optimization/116939
* gimple-fold.cc (gimple_with_undefined_signed_overflow): Return true
for VCE with integral types.
(rewrite_to_defined_overflow): Handle VCE rewriting to a cast.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
---
gcc/gimple-fold.cc | 30 ++++++++++++++++++++++++++++--
1 file changed, 28 insertions(+), 2 deletions(-)
diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
index c060ef81a42..a6a7fcbb8c1 100644
--- a/gcc/gimple-fold.cc
+++ b/gcc/gimple-fold.cc
@@ -10602,6 +10602,14 @@ gimple_with_undefined_signed_overflow (gimple *stmt)
if (!INTEGRAL_TYPE_P (lhs_type)
&& !POINTER_TYPE_P (lhs_type))
return false;
+ tree rhs = gimple_assign_rhs1 (stmt);
+ /* VCE from integral types to another integral types but with
+ different precisions need to be changed into casts
+ to be well defined. */
+ if (gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR
+ && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0)))
+ && is_gimple_val (TREE_OPERAND (rhs, 0)))
+ return true;
if (!TYPE_OVERFLOW_UNDEFINED (lhs_type))
return false;
if (!arith_code_with_undefined_signed_overflow
@@ -10630,10 +10638,28 @@ rewrite_to_defined_overflow (gimple_stmt_iterator
*gsi, gimple *stmt,
"overflow ");
print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
}
-
+ gimple_seq stmts = NULL;
+ /* VCE from integral types to another integral types but with
+ different precisions need to be changed into casts
+ to be well defined. */
+ if (gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR)
+ {
+ tree rhs = gimple_assign_rhs1 (stmt);
+ tree new_rhs = TREE_OPERAND (rhs, 0);
+ gcc_assert (is_gimple_val (new_rhs));
+ gimple_assign_set_rhs_code (stmt, NOP_EXPR);
+ gimple_assign_set_rhs1 (stmt, new_rhs);
+ if (in_place)
+ update_stmt (stmt);
+ else
+ {
+ gimple_set_modified (stmt, true);
+ gimple_seq_add_stmt (&stmts, stmt);
+ }
+ return stmts;
+ }
tree lhs = gimple_assign_lhs (stmt);
tree type = unsigned_type_for (TREE_TYPE (lhs));
- gimple_seq stmts = NULL;
if (gimple_assign_rhs_code (stmt) == ABS_EXPR)
gimple_assign_set_rhs_code (stmt, ABSU_EXPR);
else
--
2.34.1
