From 35b51468cb1306ff0a9072f25fecf0ff556705eb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Sat, 25 Jan 2014 09:22:32 +0100
Subject: [PATCH] value flow: Fixed FP for division then check in for loop:
 'for (a=b/x;x>0;x--)'

---
 lib/valueflow.cpp      | 11 +++++++++--
 test/testvalueflow.cpp |  7 +++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index c6f11f1ba..6625c33d8 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -273,7 +273,7 @@ static void valueFlowBeforeCondition(TokenList *tokenlist, ErrorLogger *errorLog
             continue;
         }
 
-        // bailout: while-condition, variable is changed in while loop
+        // bailout: for/while-condition, variable is changed in while loop
         for (const Token *tok2 = tok; tok2; tok2 = tok2->astParent()) {
             if (tok2->astParent() || tok2->str() != "(" || !Token::simpleMatch(tok2->link(), ") {"))
                 continue;
@@ -281,7 +281,14 @@ static void valueFlowBeforeCondition(TokenList *tokenlist, ErrorLogger *errorLog
             if (Token::Match(tok2->previous(), "for|while (")) {
                 const Token *start = tok2->link()->next();
                 const Token *end   = start->link();
-                if (Token::findmatch(start,"++|--| %varid% ++|--|=",end,varid)) {
+
+                if (tok2->astOperand2()->str() == ";" &&
+                    tok2->astOperand2()->astOperand2() &&
+                    tok2->astOperand2()->astOperand2()->str() == ";")
+                    start = tok2->astOperand2()->astOperand2();
+
+                if (Token::findmatch(start,"++|-- %varid%",end,varid) ||
+                    Token::findmatch(start,"%varid% ++|--|=",end,varid)) {
                     varid = 0U;
                     if (settings->debugwarnings)
                         bailout(tokenlist, errorLogger, tok, "variable " + var->nameToken()->str() + " used in loop");
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index 03e268373..fd3ca43ff 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -333,6 +333,13 @@ private:
                "    }\n"
                "}";
         ASSERT_EQUALS(false, testValueOfX(code, 2U, 0));
+
+        code = "void f(unsigned int x) {\n"
+               "    for (int a = 1000 / x;\n"
+               "         x > 0;\n"
+               "         x--) {}\n"
+               "}";
+        ASSERT_EQUALS(false, testValueOfX(code, 2U, 0));
     }
 
     void valueFlowBeforeConditionTernaryOp() { // bailout: ?: