In the face of the more complex tricks in reassoc with respect
to negate processing it can happen that the expression rewrite
is fooled to recurse on a leaf and pick up a bogus expression
code. The following patch makes the expression rewrite more
robust in providing the expression code to it directly since
it is the same for all operations in a chain.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed to master.
2020-07-30 Richard Biener <rguent...@suse.de>
PR tree-optimization/96370
* tree-ssa-reassoc.c (rewrite_expr_tree): Add operation
code parameter and use it instead of picking it up from
the stmt that is being rewritten.
(reassociate_bb): Pass down the operation code.
* gcc.dg/pr96370.c: New testcase.
---
gcc/testsuite/gcc.dg/pr96370.c | 8 ++++++++
gcc/tree-ssa-reassoc.c | 10 +++++-----
2 files changed, 13 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr96370.c
diff --git a/gcc/testsuite/gcc.dg/pr96370.c b/gcc/testsuite/gcc.dg/pr96370.c
new file mode 100644
index 00000000000..b939b2141d6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr96370.c
@@ -0,0 +1,8 @@
+/* { dg-do compile { target dfp } } */
+/* { dg-options "-O2 -ffast-math" } */
+
+void c(_Decimal128);
+void a(_Decimal128 b)
+{
+ c(-b * b);
+}
diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index d06b693ec76..266cff376e5 100644
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -4913,7 +4913,7 @@ insert_stmt_before_use (gimple *stmt, gimple
*stmt_to_insert)
recursive invocations. */
static tree
-rewrite_expr_tree (gimple *stmt, unsigned int opindex,
+rewrite_expr_tree (gimple *stmt, enum tree_code rhs_code, unsigned int opindex,
vec<operand_entry *> ops, bool changed, bool next_changed)
{
tree rhs1 = gimple_assign_rhs1 (stmt);
@@ -4960,7 +4960,7 @@ rewrite_expr_tree (gimple *stmt, unsigned int opindex,
= find_insert_point (stmt, oe1->op, oe2->op);
lhs = make_ssa_name (TREE_TYPE (lhs));
stmt
- = gimple_build_assign (lhs, gimple_assign_rhs_code (stmt),
+ = gimple_build_assign (lhs, rhs_code,
oe1->op, oe2->op);
gimple_set_uid (stmt, uid);
gimple_set_visited (stmt, true);
@@ -5004,7 +5004,7 @@ rewrite_expr_tree (gimple *stmt, unsigned int opindex,
/* Recurse on the LHS of the binary operator, which is guaranteed to
be the non-leaf side. */
tree new_rhs1
- = rewrite_expr_tree (SSA_NAME_DEF_STMT (rhs1), opindex + 1, ops,
+ = rewrite_expr_tree (SSA_NAME_DEF_STMT (rhs1), rhs_code, opindex + 1, ops,
changed || oe->op != rhs2 || next_changed,
false);
@@ -5030,7 +5030,7 @@ rewrite_expr_tree (gimple *stmt, unsigned int opindex,
gimple *insert_point = find_insert_point (stmt, new_rhs1, oe->op);
lhs = make_ssa_name (TREE_TYPE (lhs));
- stmt = gimple_build_assign (lhs, gimple_assign_rhs_code (stmt),
+ stmt = gimple_build_assign (lhs, rhs_code,
new_rhs1, oe->op);
gimple_set_uid (stmt, uid);
gimple_set_visited (stmt, true);
@@ -6477,7 +6477,7 @@ reassociate_bb (basic_block bb)
if (len >= 3)
swap_ops_for_binary_stmt (ops, len - 3, stmt);
- new_lhs = rewrite_expr_tree (stmt, 0, ops,
+ new_lhs = rewrite_expr_tree (stmt, rhs_code, 0, ops,
powi_result != NULL
|| negate_result,
len != orig_len);
--
2.26.2
