diff options
author | Andres Noetzli <andres.noetzli@gmail.com> | 2019-04-01 15:07:05 -0700 |
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committer | GitHub <noreply@github.com> | 2019-04-01 15:07:05 -0700 |
commit | 8a9ffdbb248ddcc6a41f628f6dcbc070b57e6a28 (patch) | |
tree | bf9e85f9950c2c52f7795bdebdfd0183f114060d /src/theory/fp | |
parent | 41355e412a142809f63a1939a4515486ccd4c6fb (diff) |
FP: Fix wrong model due to partial assignment (#2910)
For a simple query `(not (= (fp.isSubnormal x) false))`, we were getting
a wrong model. The issue was that `(sign x)` was not assigned a value
and did not appear in the shared terms. In
`TheoryFp::collectModelInfo()`, however, we generate an expression that
connects the components of `x` to `x`, which contains `(sign x)`. As a
result, the normalization while building a model did not result in a
constant. This commit fixes the issue by marking `(sign x)` (and
`(significand x)`) as assignable. Assignable terms can take any value
while building a model if there is no existing value.
Diffstat (limited to 'src/theory/fp')
-rw-r--r-- | src/theory/fp/theory_fp.cpp | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/src/theory/fp/theory_fp.cpp b/src/theory/fp/theory_fp.cpp index 627b87ba7..4652f62d1 100644 --- a/src/theory/fp/theory_fp.cpp +++ b/src/theory/fp/theory_fp.cpp @@ -1084,6 +1084,41 @@ bool TheoryFp::collectModelInfo(TheoryModel *m) { return false; } + + if (Configuration::isAssertionBuild() && isLeaf(node) && !node.isConst() + && node.getType().isFloatingPoint()) + { + // Check that the equality engine has asssigned values to all the + // components of `node` except `(sign node)` (the sign component is + // assignable, meaning that the model builder can pick an arbitrary value + // for it if it hasn't been assigned in the equality engine). + NodeManager* nm = NodeManager::currentNM(); + Node compNaN = nm->mkNode(kind::FLOATINGPOINT_COMPONENT_NAN, node); + Node compInf = nm->mkNode(kind::FLOATINGPOINT_COMPONENT_INF, node); + Node compZero = nm->mkNode(kind::FLOATINGPOINT_COMPONENT_ZERO, node); + Node compExponent = + nm->mkNode(kind::FLOATINGPOINT_COMPONENT_EXPONENT, node); + Node compSignificand = + nm->mkNode(kind::FLOATINGPOINT_COMPONENT_SIGNIFICAND, node); + + eq::EqualityEngine* ee = m->getEqualityEngine(); + Assert(ee->hasTerm(compNaN) && ee->getRepresentative(compNaN).isConst()); + Assert(ee->hasTerm(compInf) && ee->getRepresentative(compInf).isConst()); + Assert(ee->hasTerm(compZero) + && ee->getRepresentative(compZero).isConst()); + Assert(ee->hasTerm(compExponent) + && ee->getRepresentative(compExponent).isConst()); + Assert(ee->hasTerm(compSignificand)); + Assert(ee->getRepresentative(compSignificand).isConst()); + + // At most one of the flags (NaN, inf, zero) can be set + Node one = nm->mkConst(BitVector(1U, 1U)); + size_t numFlags = 0; + numFlags += ee->getRepresentative(compNaN) == one ? 1 : 0; + numFlags += ee->getRepresentative(compInf) == one ? 1 : 0; + numFlags += ee->getRepresentative(compZero) == one ? 1 : 0; + Assert(numFlags <= 1); + } } return true; |