Generating the constants used for recording the edges taken for
condition coverage would trigger undefined behavior when an expression
had exactly 64 (== sizeof (1ULL)) conditions, as it would generate the
constant for the next iteration at the end of the loop body, even if there
was never a next iteration. By moving the check and constant generation
to the top of the loop and hoisting the increment flag there is no
opportunity for UB.
PR 114627
gcc/ChangeLog:
* tree-profile.cc (instrument_decisions): Generate constant
at the start of loop.
---
gcc/tree-profile.cc | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/gcc/tree-profile.cc b/gcc/tree-profile.cc
index 33ff550a7bc..e58f5c83472 100644
--- a/gcc/tree-profile.cc
+++ b/gcc/tree-profile.cc
@@ -1049,6 +1049,7 @@ instrument_decisions (array_slice<basic_block> expr,
size_t condno,
zerocounter[2] = zero;
unsigned xi = 0;
+ bool increment = false;
tree rhs = build_int_cst (gcov_type_node, 1ULL << xi);
for (basic_block current : expr)
{
@@ -1057,7 +1058,14 @@ instrument_decisions (array_slice<basic_block> expr,
size_t condno,
candidates.safe_push (zerocounter);
counters prev = resolve_counters (candidates);
- int increment = 0;
+ if (increment)
+ {
+ xi += 1;
+ gcc_checking_assert (xi < sizeof (uint64_t) * BITS_PER_UNIT);
+ rhs = build_int_cst (gcov_type_node, 1ULL << xi);
+ increment = false;
+ }
+
for (edge e : current->succs)
{
counters next = prev;
@@ -1072,7 +1080,7 @@ instrument_decisions (array_slice<basic_block> expr,
size_t condno,
tree m = build_int_cst (gcov_type_node, masks[2*xi + k]);
next[2] = emit_bitwise_op (e, prev[2], BIT_IOR_EXPR, m);
}
- increment = 1;
+ increment = true;
}
else if (e->flags & EDGE_COMPLEX)
{
@@ -1085,11 +1093,13 @@ instrument_decisions (array_slice<basic_block> expr,
size_t condno,
}
table.get_or_insert (e->dest).safe_push (next);
}
- xi += increment;
- if (increment)
- rhs = build_int_cst (gcov_type_node, 1ULL << xi);
}
+ /* Since this is also the return value, the number of conditions, make sure
+ to include the increment of the last basic block. */
+ if (increment)
+ xi += 1;
+
gcc_assert (xi == bitmap_count_bits (core));
const tree relaxed = build_int_cst (integer_type_node, MEMMODEL_RELAXED);
--
2.30.2
