From 2c558d2655cb22f472c83e8296b5cd2a92365cd3 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Thu, 30 Jul 2020 10:24:42 +0200 Subject: [PATCH] tree-optimization/96370 - make reassoc expr rewrite more robust 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. 2020-07-30 Richard Biener 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 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); -- 2.30.2