diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index aa646360d..d76757589 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -7613,10 +7613,10 @@ bool Tokenizer::simplifyCalculations()
         {
             if (tok->str() == "0")
             {
-                if (Token::Match(tok->previous(), "[+-] 0"))
+                if (Token::Match(tok->previous(), "[+-|] 0"))
                 {
                     tok = tok->previous();
-                    if (Token::Match(tok->tokAt(-4), "[;{}] %var% = %var% [+-] 0 ;") &&
+                    if (Token::Match(tok->tokAt(-4), "[;{}] %var% = %var% [+-|] 0 ;") &&
                         tok->strAt(-3) == tok->strAt(-1))
                     {
                         tok = tok->previous()->previous()->previous();
@@ -7628,7 +7628,7 @@ bool Tokenizer::simplifyCalculations()
                     tok->deleteThis();
                     ret = true;
                 }
-                else if (Token::Match(tok->previous(), "[=([,] 0 +"))
+                else if (Token::Match(tok->previous(), "[=([,] 0 [+|]"))
                 {
                     tok->deleteThis();
                     tok->deleteThis();
@@ -7646,7 +7646,7 @@ bool Tokenizer::simplifyCalculations()
 
             if (Token::simpleMatch(tok->previous(), "* 1") || Token::simpleMatch(tok, "1 *"))
             {
-                if (Token::simpleMatch(tok->previous(), "*"))
+                if (tok->previous()->isOp())
                     tok = tok->previous();
                 tok->deleteThis();
                 tok->deleteThis();
@@ -7664,10 +7664,12 @@ bool Tokenizer::simplifyCalculations()
 
             if (Token::simpleMatch(tok->previous(), "( 0 ||") ||
                 Token::simpleMatch(tok->previous(), "|| 0 )") ||
+                Token::simpleMatch(tok->previous(), "( 0 |") ||
+                Token::simpleMatch(tok->previous(), "| 0 )") ||
                 Token::simpleMatch(tok->previous(), "( 1 &&") ||
                 Token::simpleMatch(tok->previous(), "&& 1 )"))
             {
-                if (!Token::simpleMatch(tok->previous(), "("))
+                if (tok->previous()->isOp())
                     tok = tok->previous();
                 tok->deleteThis();
                 tok->deleteThis();
diff --git a/test/testtokenize.cpp b/test/testtokenize.cpp
index 06fd80ac8..4cdeb213c 100644
--- a/test/testtokenize.cpp
+++ b/test/testtokenize.cpp
@@ -323,6 +323,8 @@ private:
 
         TEST_CASE(simplifyLogicalOperators);
 
+        TEST_CASE(simplifyCalculations); // ticket #2870
+
         // foo(p = new char[10]);  =>  p = new char[10]; foo(p);
         TEST_CASE(simplifyAssignmentInFunctionCall);
 
@@ -5574,6 +5576,20 @@ private:
         ASSERT_EQUALS("if ( a != b )", tokenizeAndStringify("if (a not_eq b)"));
     }
 
+    void simplifyCalculations()
+    {
+	ASSERT_EQUALS("void foo ( char str [ ] ) { char x ; x = * str ; }",
+		      tokenizeAndStringify("void foo ( char str [ ] ) { char x = 0 | ( * str ) ; }", true));
+        ASSERT_EQUALS("void foo ( ) { if ( b ) { } }",
+                      tokenizeAndStringify("void foo ( ) { if (b | 0) { } }", true));
+        ASSERT_EQUALS("void foo ( ) { if ( b ) { } }",
+                      tokenizeAndStringify("void foo ( ) { if (0 | b) { } }", true));
+        ASSERT_EQUALS("void foo ( int b ) { int a ; a = b ; bar ( a ) ; }",
+                      tokenizeAndStringify("void foo ( int b ) { int a = b | 0 ; bar ( a ) ; }", true));
+        ASSERT_EQUALS("void foo ( int b ) { int a ; a = b ; bar ( a ) ; }",
+                      tokenizeAndStringify("void foo ( int b ) { int a = 0 | b ; bar ( a ) ; }", true));
+    }
+
     void simplifyCompoundAssignment()
     {
         ASSERT_EQUALS("; x = x + y ;", tokenizeAndStringify("; x += y;"));