The following avoids applying TER to possibly trapping expressions,
preventing a trapping FP multiplication to be moved across a call
that should not be executed.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
2021-08-31 Richard Biener <rguent...@suse.de>
PR middle-end/102129
* tree-ssa-ter.c (find_replaceable_in_bb): Do not move
possibly trapping expressions across calls.
---
gcc/tree-ssa-ter.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/gcc/tree-ssa-ter.c b/gcc/tree-ssa-ter.c
index 9eb8a11a7c0..3a057c2d25f 100644
--- a/gcc/tree-ssa-ter.c
+++ b/gcc/tree-ssa-ter.c
@@ -658,11 +658,15 @@ find_replaceable_in_bb (temp_expr_table *tab, basic_block
bb)
substitution list, or the def and use span a call such that
we'll expand lifetimes across a call. We also don't want to
replace across these expressions that may call libcalls that
- clobber the register involved. See PR 70184. */
+ clobber the register involved. See PR 70184. Neither
+ do we want to move possibly trapping expressions across
+ a call. See PRs 102129 and 33593. */
if (gimple_has_volatile_ops (stmt) || same_root_var
|| (tab->call_cnt[ver] != cur_call_cnt
- && SINGLE_SSA_USE_OPERAND (SSA_NAME_DEF_STMT (use),
SSA_OP_USE)
- == NULL_USE_OPERAND_P)
+ && (SINGLE_SSA_USE_OPERAND (SSA_NAME_DEF_STMT (use),
+ SSA_OP_USE)
+ == NULL_USE_OPERAND_P
+ || gimple_could_trap_p (SSA_NAME_DEF_STMT (use))))
|| tab->reg_vars_cnt[ver] != cur_reg_vars_cnt)
finished_with_expr (tab, ver, true);
else
--
2.31.1
