From: Andres Noetzli <andres.noetzli@gmail.com>
Date: Tue, 30 Apr 2019 19:32:50 +0000 (-0700)
Subject: Fix concat-find regexp elimination (#2983)
X-Git-Tag: cvc5-1.0.0~4157
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d998d5e4213503e0913581d57c09ad486cded5c1;p=cvc5.git

Fix concat-find regexp elimination (#2983)
---

diff --git a/src/theory/strings/regexp_elim.cpp b/src/theory/strings/regexp_elim.cpp
index afffce2c8..b6a997629 100644
--- a/src/theory/strings/regexp_elim.cpp
+++ b/src/theory/strings/regexp_elim.cpp
@@ -347,10 +347,10 @@ Node RegExpElimination::eliminateConcat(Node atom)
   for (unsigned r = 0; r < 2; r++)
   {
     unsigned index = r == 0 ? 0 : nchildren - 1;
-    Assert(children[index + (r == 0 ? 1 : -1)].getKind() != STRING_TO_REGEXP);
     Node c = children[index];
     if (c.getKind() == STRING_TO_REGEXP)
     {
+      Assert(children[index + (r == 0 ? 1 : -1)].getKind() != STRING_TO_REGEXP);
       Node s = c[0];
       Node lens = nm->mkNode(STRING_LENGTH, s);
       Node sss = r == 0 ? d_zero : nm->mkNode(MINUS, lenx, lens);
@@ -375,9 +375,9 @@ Node RegExpElimination::eliminateConcat(Node atom)
       rexpElimChildren.push_back(c);
     }
   }
-  Assert(rexpElimChildren.size() + sConstraints.size() == nchildren);
   if (!sConstraints.empty())
   {
+    Assert(rexpElimChildren.size() + sConstraints.size() == nchildren);
     Node ss = nm->mkNode(STRING_SUBSTR, x, sStartIndex, sLength);
     Assert(!rexpElimChildren.empty());
     Node regElim =
@@ -412,7 +412,7 @@ Node RegExpElimination::eliminateConcat(Node atom)
         Node bound =
             nm->mkNode(AND,
                        nm->mkNode(LEQ, d_zero, k),
-                       nm->mkNode(LT, k, nm->mkNode(MINUS, lenx, lens)));
+                       nm->mkNode(LEQ, k, nm->mkNode(MINUS, lenx, lens)));
         echildren.push_back(bound);
       }
       Node substrEq = nm->mkNode(STRING_SUBSTR, x, k, lens).eqNode(s);
diff --git a/test/regress/CMakeLists.txt b/test/regress/CMakeLists.txt
index d8adbb59e..714459a85 100644
--- a/test/regress/CMakeLists.txt
+++ b/test/regress/CMakeLists.txt
@@ -1537,6 +1537,7 @@ set(regress_1_tests
   regress1/strings/issue2060.smt2
   regress1/strings/issue2429-code.smt2
   regress1/strings/issue2981.smt2
+  regress1/strings/issue2982.smt2
   regress1/strings/kaluza-fl.smt2
   regress1/strings/loop002.smt2
   regress1/strings/loop003.smt2
diff --git a/test/regress/regress1/strings/issue2982.smt2 b/test/regress/regress1/strings/issue2982.smt2
new file mode 100644
index 000000000..41be8d1fd
--- /dev/null
+++ b/test/regress/regress1/strings/issue2982.smt2
@@ -0,0 +1,23 @@
+; COMMAND-LINE: --strings-exp --re-elim --re-elim-agg
+; EXPECT: unsat
+(set-logic QF_SLIA)
+
+(declare-fun var_0 () String)
+(declare-fun var_1 () String)
+(declare-fun var_2 () String)
+(declare-fun var_3 () String)
+(declare-fun var_4 () String)
+(declare-fun var_5 () String)
+(declare-fun var_6 () String)
+(declare-fun var_7 () String)
+(declare-fun var_8 () String)
+(declare-fun var_9 () String)
+(declare-fun var_10 () String)
+(declare-fun var_11 () String)
+(declare-fun var_12 () String)
+
+(assert (str.in.re (str.++ var_7 "z" var_7 ) (re.* (str.to.re "z"))))
+(assert (str.in.re var_7 (re.* (re.range "a" "u"))))
+(assert (not (str.in.re (str.++ "a" var_7 "z" "a" var_7 ) (re.++ (re.* (re.union (str.to.re "z") (re.++ (str.to.re "a") (re.++ (re.* (str.to.re "a")) (str.to.re "z"))))) (re.++ (str.to.re "a") (re.* (str.to.re "a")))))))
+(assert (and (<= (str.len var_7) 0 ) (<= 0  (str.len var_7))))
+(check-sat)