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tree-optimization/114624 - fix use-after-free in SCCP

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We're inspecting the replaced PHI node after releasing it.

	PR tree-optimization/114624
	* tree-scalar-evolution.cc (final_value_replacement_loop):
	Get at the PHI arg location before releasing the PHI node.

	* gcc.dg/torture/pr114624.c: New testcase.
This commit is contained in:
Richard Biener 2024-04-08 10:38:49 +02:00
parent 7d051f7d45
commit 97d5cd8740
2 changed files with 22 additions and 2 deletions
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20
gcc/testsuite/gcc.dg/torture/pr114624.c Normal file
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@ -0,0 +1,20 @@
/* { dg-do compile } */
int a, b;
int main() {
int c, d = 1;
while (a) {
while (b)
if (d)
while (a)
;
for (; b < 2; b++)
if (b)
for (c = 0; c < 8; c++)
d = 0;
else
for (a = 0; a < 2; a++)
;
}
return 0;
}

4
gcc/tree-scalar-evolution.cc
View File

@ -3877,6 +3877,7 @@ final_value_replacement_loop (class loop *loop)
to a GIMPLE sequence or to a statement list (keeping this a
GENERIC interface). */
def = unshare_expr (def);
auto loc = gimple_phi_arg_location (phi, exit->dest_idx);
remove_phi_node (&psi, false);
/* Propagate constants immediately, but leave an unused initialization
@ -3888,8 +3889,7 @@ final_value_replacement_loop (class loop *loop)
gimple_seq stmts;
def = force_gimple_operand (def, &stmts, false, NULL_TREE);
gassign *ass = gimple_build_assign (rslt, def);
gimple_set_location (ass,
gimple_phi_arg_location (phi, exit->dest_idx));
gimple_set_location (ass, loc);
gimple_seq_add_stmt (&stmts, ass);
/* If def's type has undefined overflow and there were folded