From f10634c021a8b173cea5e0eb6030fcd9e6cbef58 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Wed, 23 Aug 2017 17:52:28 +0200
Subject: [PATCH] ValueFlow: Dont try to evaluate '/=0;'

---
 lib/valueflow.cpp      | 22 ++++++++++++++++------
 test/testvalueflow.cpp |  7 +++++++
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 143b28ed4..4e9dc83a1 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -1684,17 +1684,24 @@ static bool valueFlowForward(Token * const               startToken,
                 // Erase values that are not int values..
                 for (it = values.begin(); it != values.end();) {
                     if (it->isIntValue()) {
+                        bool ub = false;
                         if (assign == "+=")
                             it->intvalue += rhsValue.intvalue;
                         else if (assign == "-=")
                             it->intvalue -= rhsValue.intvalue;
                         else if (assign == "*=")
                             it->intvalue *= rhsValue.intvalue;
-                        else if (assign == "/=")
-                            it->intvalue /= rhsValue.intvalue;
-                        else if (assign == "%=")
-                            it->intvalue %= rhsValue.intvalue;
-                        else if (assign == "&=")
+                        else if (assign == "/=") {
+                            if (rhsValue.intvalue == 0)
+                                ub = true;
+                            else
+                                it->intvalue /= rhsValue.intvalue;
+                        } else if (assign == "%=") {
+                            if (rhsValue.intvalue == 0)
+                                ub = true;
+                            else
+                                it->intvalue %= rhsValue.intvalue;
+                        } else if (assign == "&=")
                             it->intvalue &= rhsValue.intvalue;
                         else if (assign == "|=")
                             it->intvalue |= rhsValue.intvalue;
@@ -1704,7 +1711,10 @@ static bool valueFlowForward(Token * const               startToken,
                             values.clear();
                             break;
                         }
-                        ++it;
+                        if (ub)
+                            it = values.erase(it);
+                        else
+                            ++it;
                     } else if (it->isFloatValue()) {
                         if (assign == "+=")
                             it->floatValue += rhsValue.intvalue;
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index a563edf8a..6c598a1b2 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -1746,6 +1746,13 @@ private:
                "}";
         ASSERT_EQUALS(true, testValueOfX(code, 4U, 166));
 
+        code = "void f() {\n"
+               "    int x = 123;\n"
+               "    x /= 0;\n" // don't crash when evaluating x/=0
+               "    return x;\n"
+               "}";
+        ASSERT_EQUALS(false, testValueOfX(code, 4U, 123));
+
         code = "void f() {\n"
                "    float x = 123.45;\n"
                "    x += 67;\n"