Automatic Equivalence Checking of UF+IA Programs

Proving equivalence of programs has several important applications, including algorithm recognition, regression checking, compiler optimization verification and validation, and information flow checking. Despite being a topic with so many important applications, program equivalence checking has seen little advances over the past decades due to its inherent (high) complexity. In this paper, we propose, to the best of our knowledge, the first semi-algorithm for the automatic verification of partial equivalence of two programs over the combined theory of uninterpreted function symbols and integer arithmetic (UF+IA). The proposed algorithm supports, in particular, programs with nested loops. The crux of the technique is a transformation of uninterpreted functions (UFs) applications into integer polynomials, which enables the precise summarization of loops with UF applications using recurrences. The equivalence checking algorithm then proceeds on loop-free, integer only programs. We implemented the proposed technique in CORK, a tool that automatically verifies the correctness of compiler optimizations, and we show that it can prove more optimizations correct than state-of-the-art techniques.

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“…This paper extends the work presented at the International SPIN Symposium on Model Checking of Software 2013 [47].…”

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confidence: 54%

Automatic equivalence checking of programs with uninterpreted functions and integer arithmetic

Lopes

Monteiro

2015

Int J Softw Tools Technol Transfer

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“…This BMC only checks optimizations for partial correctness, and therefore the results we present in this section are weakest liberal preconditions. We did not use our own verification tool, CORK [25], since it is several orders of magnitude slower at producing counterexamples than our simple BMC. Furthermore, CORK does not support disjunctive preconditions natively, and therefore it has to first convert such preconditions to DNF and test each of the conjuncts separately.…”

Section: Discussionmentioning

confidence: 99%

“…Our precondition synthesis algorithm, named PSyCO, is counterexample-guided. The algorithm relies on a verification tool as a black box that can prove the correctness of optimizations (such as CORK [25] or PEC [20]) or return a counterexample otherwise.…”

Section: The Algorithmmentioning

confidence: 99%

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Weakest Precondition Synthesis for Compiler Optimizations

Lopes

Monteiro

2014

Lecture Notes in Computer Science

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Compiler optimizations play an increasingly important role in code generation. This is especially true with the advent of resourcelimited mobile devices. We rely on compiler optimizations to improve performance, reduce code size, and reduce power consumption of our programs. Despite being a mature field, compiler optimizations are still designed and implemented by hand, and usually without providing any guarantee of correctness. In addition to devising the code transformations, designers and implementers have to come up with an analysis that determines in which cases the optimization can be safely applied. In other words, the optimization designer has to specify a precondition that ensures that the optimization is semantics-preserving. However, devising preconditions for optimizations by hand is a non-trivial task. It is easy to specify a precondition that, although correct, is too restrictive, and therefore misses some optimization opportunities. In this paper, we propose, to the best of our knowledge, the first algorithm for the automatic synthesis of preconditions for compiler optimizations. The synthesized preconditions are provably correct by construction, and they are guaranteed to be the weakest in the precondition language that we consider. We implemented the proposed technique in a tool named PSyCO. We present examples of preconditions synthesized by PSyCO, as well as the results of running PSyCO on a set of optimizations.

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“…In the cases of pediatric oncologic patients, the ideal is that they be examined by a oral health professional as soon as their diseases are diagnosed, in order to the dentistry treatment to be conducted before the beginning of the oncologic treatment 6 . When there is integration between the dental surgeon and oncologist doctor, the risks of systemic complications are minimized 3 .…”

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The caries experience and dentistry following evaluation of children submitted to antineoplastic therapy

Hanna¹,

Araújo²,

Vilarino³

et al. 2016

J. res. dent.

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Aim: To evaluate the caries experience and the dentistry following of children submitted to antineoplastic therapy of a reference Hospital to this type of treatment in Para state, Brazil. Material and Methods:The sample consisted of 46 children. It was included children in the ages of 2 to 12 years diagnosed with cancer that would be submitted to chemotherapy treatment. The evaluation was performed before the chemotherapy treatment and consisted of anamnesis and oral clinical examination. In order to decrease the interexaminer diagnosis variability and increase the data surveys confidentiality, a previous training and calibration was performed before the beginning of the examination.Results: There was a higher prevalence of childish cancer among male gender children. The age group more affected was between 8 to 12 years. There was a bigger percentage of patients that didn't go to the dentist before the chemotherapy treatment. The children caries experience was evaluated by the CPO-D and medium Ceo-d indexes, obtaining respectively the values of 4,75 and 0,47. Conclusions:The initial caries experience was high comparing to the international and Brazil average. Most of researched children didn't have a previous dentistry care before the beginning of antineoplastic therapy.

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Automatic Equivalence Checking of UF+IA Programs

Cited by 5 publications

References 53 publications

Automatic equivalence checking of programs with uninterpreted functions and integer arithmetic

Automatic equivalence checking of programs with uninterpreted functions and integer arithmetic

Weakest Precondition Synthesis for Compiler Optimizations

The caries experience and dentistry following evaluation of children submitted to antineoplastic therapy

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