https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101068
Bug ID: 101068
Summary: Analyzer does not purge constraints in loops (e.g. in
explode-2.c)
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: analyzer
Assignee: dmalcolm at gcc dot gnu.org
Reporter: dmalcolm at gcc dot gnu.org
Target Milestone: ---
Looking at gcc.dg/analyzer/explode-2.c, it appears that it treats the SSA names
for the results of the two "get" calls as constant within the loop i.e. they
acquire constraints on the first iteration due to the while/switch edges that
are taken, and these constraints aren't purged when processing subsequent
iterations.
Hence, rather than:
while (get ())
{
switch (get ())
{
[...snip...]
}
}
the analyzer effectively treats this as:
int a, b;
a = get ();
b = get ();
while (a)
{
switch (b)
{
[...snip...]
}
}
and this artifically helps stop this testcase from exploding.
