From 1e3c43e708ed613ed26ad52110e34216c70cd3ee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Wed, 8 Jan 2014 06:39:15 +0100
Subject: [PATCH] value flow: improved bailouts in ?:

---
 lib/valueflow.cpp      | 17 +++++++++++------
 test/testvalueflow.cpp | 25 ++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 53795bc66..db48285df 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -50,7 +50,7 @@ static void valueFlowBeforeCondition(TokenList *tokenlist, ErrorLogger *errorLog
         unsigned int varid;
         MathLib::bigint num;
         const Variable *var;
-        if (Token::Match(tok, "==|!=|>=|<=") && tok->astOperand1() && tok->astOperand2()) {
+        if (tok->isComparisonOp() && tok->astOperand1() && tok->astOperand2()) {
             if (tok->astOperand1()->isName() && tok->astOperand2()->isNumber()) {
                 varid = tok->astOperand1()->varId();
                 var = tok->astOperand1()->variable();
@@ -62,11 +62,6 @@ static void valueFlowBeforeCondition(TokenList *tokenlist, ErrorLogger *errorLog
             } else {
                 continue;
             }
-            if (Token::Match(tok->astParent(), "[?:]")) {
-                if (settings->debugwarnings)
-                    bailout(tokenlist, errorLogger, tok, "variable " + var->nameToken()->str() + " stopping on " + tok->astParent()->str());
-                continue;
-            }
         } else if (Token::Match(tok->previous(), "if|while ( %var% %oror%|&&|)") ||
                    Token::Match(tok, "%oror%|&& %var% %oror%|&&|)")) {
             varid = tok->next()->varId();
@@ -111,6 +106,16 @@ static void valueFlowBeforeCondition(TokenList *tokenlist, ErrorLogger *errorLog
                     break;
                 }
 
+                // skip if variable is conditionally used in ?: expression.
+                const Token *parent = tok2->astParent();
+                while (parent && !Token::Match(parent, "[?:]"))
+                    parent = parent->astParent();
+                if (parent) {
+                    if (settings->debugwarnings)
+                        bailout(tokenlist, errorLogger, tok2, "no simplification of " + tok2->str() + " within ?: expression");
+                    continue;
+                }
+
                 tok2->values.push_back(val);
                 if (var && tok2 == var->nameToken())
                     break;
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index d8a04f6cf..71904b601 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -76,17 +76,32 @@ private:
 
 
     void valueFlowBeforeCondition() {
-        const char code[] = "void f(int x) {\n"
-                            "    int a = x;\n"
-                            "    if (x == 123) {}\n"
-                            "}";
+        const char *code;
+
+        code = "void f(int x) {\n"
+               "    int a = x;\n"
+               "    if (x == 123) {}\n"
+               "}";
         ASSERT_EQUALS(true, testValueOfX(code, 2U, 123));
 
         // bailout: ?:
         bailout("void f(int x) {\n"
                 "    y = ((x<0) ? x : ((x==2)?3:4));\n"
                 "}");
-        ASSERT_EQUALS("[test.cpp:2]: (debug) ValueFlow bailout: variable x stopping on :\n", errout.str());
+        ASSERT_EQUALS("[test.cpp:2]: (debug) ValueFlow bailout: no simplification of x within ?: expression\n", errout.str());
+
+        bailout("int f(int x) {\n"
+                "  int r = x ? 1 / x : 0;\n"
+                "  if (x == 0) {}\n"
+                "}");
+        ASSERT_EQUALS("[test.cpp:2]: (debug) ValueFlow bailout: no simplification of x within ?: expression\n", errout.str());
+
+        code = "void f(int x) {\n"
+               "    int a = x;\n"
+               "    a = b ? x/2 : 20/x;\n"
+               "    if (x == 123) {}\n"
+               "}";
+        ASSERT_EQUALS(true, testValueOfX(code, 2U, 123));
 
         // bailout: if/else/etc
         bailout("void f(int x) {\n"