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Amongst the inputs to the analyzer state machines that can lead to state
transitions are conditions on CFG edges, such as a test for a pointer
being non-NULL.
These conditionals can be non-trivial to determine in the face of
optimization. For example, at -O2:
if (p == NULL || q == NULL)
is optimized on some targets (e.g. x86_64) to a bitwise-or:
_1 = p_5(D) == 0B;
_2 = q_6(D) == 0B;
_3 = _1 | _2;
if (_3 != 0)
goto <bb 4>; [51.12%]
else
goto <bb 3>; [48.88%]
but on other targets (e.g. powerpc64le) as control flow:
if (p_2(D) == 0B)
goto <bb 5>; [18.09%]
else
goto <bb 3>; [81.91%]
<bb 3> [local count: 879501929]:
if (q_3(D) == 0B)
goto <bb 5>; [30.95%]
else
goto <bb 4>; [69.05%]
region_model::add_any_constraints_from_ssa_def_stmt attempts to walk
SSA def chains to reconstruct the conditions that hold, so that
e.g. in the above case of bitwise-or, the state machine for
"p" can transition to the "known-null" state along the edge leading
to bb 3.
In gcc.dg/analyzer/pattern-test-2.c I attempted to write test coverage
for this, but the test fails on those targets for which the || is
expressed via control flow.
This patch rewrites the test to make explicit use of bitwise-or, and
adds coverage for bitwise-and for good measure.
gcc/testsuite/ChangeLog:
PR analyzer/93291
* gcc.dg/analyzer/pattern-test-2.c: Remove include of stdlib.h.
(test_2): Rewrite to explicitly perform a bitwise-or of two
boolean conditions.
(test_3): New function, to test bitwise-and.
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