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middle-end/102129 - avoid TER of possibly trapping expressions

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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.

2021-08-31  Richard Biener  <rguenther@suse.de>

	PR middle-end/102129
	* tree-ssa-ter.c (find_replaceable_in_bb): Do not move
	possibly trapping expressions across calls.
This commit is contained in:
Richard Biener 2021-08-31 09:13:20 +02:00
parent dd779c509e
commit 5e57bacf6f
1 changed files with 7 additions and 3 deletions
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10
gcc/tree-ssa-ter.c
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@ -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