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Simplification of pointer comparison: do not assume numeric types #5689

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Merged
merged 1 commit into from
Dec 25, 2020
Merged

Simplification of pointer comparison: do not assume numeric types #5689

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16 changes: 16 additions & 0 deletions regression/cbmc-library/memcpy-06/main.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
// #include <string.h> is intentionally missing

struct c
{
};

int d()
{
struct c e;
memcpy(e);
}
int main()
{
int (*h)() = d;
h();
}
10 changes: 10 additions & 0 deletions regression/cbmc-library/memcpy-06/test.desc
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@@ -0,0 +1,10 @@
CORE
main.c

function 'memcpy' is not declared
parameter "memcpy::dst" type mismatch
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⛏️ mixture of " and '

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It seems there's some more work after #4875 left to be done. I'll create a separate PR for this.

^EXIT=6$
^SIGNAL=0$
--
^warning: ignoring
Invariant check failed
15 changes: 10 additions & 5 deletions src/util/simplify_expr_int.cpp
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Expand Up @@ -1645,14 +1645,19 @@ simplify_exprt::resultt<> simplify_exprt::simplify_inequality_rhs_is_constant(
}
}
else if(
expr.op0().id() == ID_typecast &&
expr.op0().type().id() == ID_pointer &&
(to_typecast_expr(expr.op0()).op().type().id() == ID_pointer ||
config.ansi_c.NULL_is_zero))
expr.op0().id() == ID_typecast && expr.op0().type().id() == ID_pointer)
{
exprt op = to_typecast_expr(expr.op0()).op();
if(
op.type().id() != ID_pointer &&
(!config.ansi_c.NULL_is_zero || !is_number(op.type()) ||
op.type().id() == ID_complex))
{
return unchanged(expr);
}

// (type)ptr == NULL -> ptr == NULL
// note that 'ptr' may be an integer
exprt op = to_typecast_expr(expr.op0()).op();
auto new_expr = expr;
new_expr.op0().swap(op);
if(new_expr.op0().type().id() != ID_pointer)
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