From b80d06b69efc092bdfab04a354d5235ee8c88f3c Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Tue, 7 Jun 2022 21:13:31 +0200
Subject: [PATCH] Don't warn for 'x | MACRO' when MACRO is 0 (#4176)

---
 lib/checkcondition.cpp | 8 ++++----
 test/testcondition.cpp | 6 ++++++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/checkcondition.cpp b/lib/checkcondition.cpp
index 85e60ac18..4c3597396 100644
--- a/lib/checkcondition.cpp
+++ b/lib/checkcondition.cpp
@@ -311,11 +311,11 @@ void CheckCondition::checkBadBitmaskCheck()
             if (isBoolean && isTrue)
                 badBitmaskCheckError(tok);
 
-            const bool isNoOp = (tok->astOperand1()->hasKnownIntValue() && tok->astOperand1()->values().front().intvalue == 0) ||
-                                (tok->astOperand2()->hasKnownIntValue() && tok->astOperand2()->values().front().intvalue == 0);
+            const bool isZero1 = (tok->astOperand1()->hasKnownIntValue() && tok->astOperand1()->values().front().intvalue == 0);
+            const bool isZero2 = (tok->astOperand2()->hasKnownIntValue() && tok->astOperand2()->values().front().intvalue == 0);
 
-            if (isNoOp && !tok->isExpandedMacro())
-                badBitmaskCheckError(tok, isNoOp);
+            if ((isZero1 || isZero2) && !tok->isExpandedMacro() && !(isZero1 && tok->astOperand1()->isExpandedMacro()) && !(isZero2 && tok->astOperand2()->isExpandedMacro()))
+                badBitmaskCheckError(tok, /*isNoOp*/ true);
         }
     }
 }
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index 0af7221d7..c73a04040 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -899,6 +899,12 @@ private:
               "    return EIGHTTOIS(0);\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        check("#define O_RDONLY 0\n"
+              "void f(const char* s, int* pFd) {\n"
+              "    *pFd = open(s, O_RDONLY | O_BINARY, 0);\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }