From 52b4aeb279bad25f9bf31aa863a97306777e6aaf Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Thu, 7 Apr 2022 10:42:57 +0200
Subject: [PATCH] Fix  #10792 FP knownConditionTrueFalse with double to int
 cast (#3964)

---
 lib/astutils.cpp       |  3 +++
 lib/valueflow.cpp      |  4 ++--
 test/testcondition.cpp | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/lib/astutils.cpp b/lib/astutils.cpp
index b47d67f3f..502cc3c49 100644
--- a/lib/astutils.cpp
+++ b/lib/astutils.cpp
@@ -949,6 +949,9 @@ static const Token * followVariableExpression(const Token * tok, bool cpp, const
         return tok;
     if (isStructuredBindingVariable(var))
         return tok;
+    // assigning a floating point value to an integer does not preserve the value
+    if (var->valueType() && var->valueType()->isIntegral() && varTok->valueType() && varTok->valueType()->isFloat())
+        return tok;
     const Token * lastTok = precedes(tok, end) ? end : tok;
     // If this is in a loop then check if variables are modified in the entire scope
     const Token * endToken = (isInLoopCondition(tok) || isInLoopCondition(varTok) || var->scope() != tok->scope()) ? var->scope()->bodyEnd : lastTok;
diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index fcafd6bb2..27ca49126 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -253,12 +253,12 @@ const Token *parseCompareInt(const Token *tok, ValueFlow::Value &true_value, Val
                 value1.clear();
         }
         if (!value1.empty()) {
-            if (isSaturated(value1.front()))
+            if (isSaturated(value1.front()) || astIsFloat(tok->astOperand2(), /*unknown*/ false))
                 return nullptr;
             setConditionalValues(tok, true, value1.front(), true_value, false_value);
             return tok->astOperand2();
         } else if (!value2.empty()) {
-            if (isSaturated(value2.front()))
+            if (isSaturated(value2.front()) || astIsFloat(tok->astOperand1(), /*unknown*/ false))
                 return nullptr;
             setConditionalValues(tok, false, value2.front(), true_value, false_value);
             return tok->astOperand1();
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index 27e9650f6..744b4da50 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -2491,6 +2491,14 @@ private:
               "  if (!b && f()) {}\n"
               "}");
         ASSERT_EQUALS("", errout.str());
+
+        check("void f(double d) {\n"
+              "    if (d != 0) {\n"
+              "        int i = d;\n"
+              "        if (i == 0) {}\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void identicalInnerCondition() {
@@ -4018,6 +4026,31 @@ private:
               "}\n");
         ASSERT_EQUALS("[test.cpp:5]: (style) Condition 'w' is always true\n", errout.str());
 
+        check("void f(double d) {\n" // #10792
+              "    if (d != 0) {\n"
+              "        int i = (int)d;\n"
+              "        if (i == 0) {}\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f(double d) {\n"
+              "    if (0 != d) {\n"
+              "        int i = (int)d;\n"
+              "        if (i == 0) {}\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("struct A { double d; }\n"
+              "void f(A a) {\n"
+              "    if (a.d != 0) {\n"
+              "        int i = a.d;\n"
+              "        if (i == 0) {}\n"
+              "    }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
         check("void f() {\n"
               "    if(strlen(\"abc\") == 3) {;}\n"
               "    if(strlen(\"abc\") == 1) {;}\n"