Add clang-tidy check to suggest replacement of conditional statement with std::min/std::max (#77816)

This pull request fixes #64914 where author suggests adding a
readability check to propose the replacement of conditional statements
with std::min/std::max for improved code readability. Additionally,
reference is made to PyLint's similar checks:
[consider-using-min-builtin](https://pylint.pycqa.org/en/latest/user_guide/messages/refactor/consider-using-min-builtin.html)
and
[consider-using-max-builtin](https://pylint.pycqa.org/en/latest/user_guide/messages/refactor/consider-using-max-builtin.html)

1 files changed, 254 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/use-std-min-max.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/use-std-min-max.cpp
new file mode 100644
index 0000000..9c0e2ea
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/use-std-min-max.cpp
@@ -0,0 +1,254 @@
+// RUN: %check_clang_tidy -std=c++11-or-later %s readability-use-std-min-max %t -- -- -fno-delayed-template-parsing
+#define MY_MACRO_MIN(a, b) ((a) < (b) ? (a) : (b))
+
+constexpr int myConstexprMin(int a, int b) {
+  return a < b ? a : b;
+}
+
+constexpr int myConstexprMax(int a, int b) {
+  return a > b ? a : b;
+}
+
+#define MY_IF_MACRO(condition, statement) \
+  if (condition) {                        \
+    statement                             \
+  }                                       
+
+class MyClass {
+public:
+  int member1;
+  int member2;
+};
+
+template<typename T>
+
+void foo(T value7) {
+  int value1,value2,value3;
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max(value1, value2);
+  if (value1 < value2)
+    value1 = value2; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value2 = std::min(value1, value2);
+  if (value1 < value2)
+    value2 = value1; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `>` [readability-use-std-min-max]
+  // CHECK-FIXES: value2 = std::min(value2, value1);
+  if (value2 > value1)
+    value2 = value1; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `>` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max(value2, value1);
+  if (value2 > value1)
+    value1 = value2; 
+
+  // No suggestion needed here
+  if (value1 == value2)
+    value1 = value2;
+
+  // CHECK-MESSAGES: :[[@LINE+3]]:3: warning: use `std::max` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max<int>(value1, value4);
+  short value4;
+  if(value1<value4)
+    value1=value4; 
+  
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value3 = std::min(value1+value2, value3);
+  if(value1+value2<value3)
+    value3 = value1+value2; 
+  
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max(value1, myConstexprMin(value2, value3));
+  if (value1 < myConstexprMin(value2, value3))
+    value1 = myConstexprMin(value2, value3); 
+  
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `>` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::min(value1, myConstexprMax(value2, value3));
+  if (value1 > myConstexprMax(value2, value3))
+    value1 = myConstexprMax(value2, value3); 
+  
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `<=` [readability-use-std-min-max]
+  // CHECK-FIXES: value2 = std::min(value1, value2);
+  if (value1 <= value2)
+    value2 = value1; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `<=` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max(value1, value2);
+  if (value1 <= value2)
+    value1 = value2; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `>=` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max(value2, value1);
+  if (value2 >= value1)
+    value1 = value2; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `>=` [readability-use-std-min-max]
+  // CHECK-FIXES: value2 = std::min(value2, value1);
+  if (value2 >= value1)
+    value2 = value1; 
+  
+  // CHECK-MESSAGES: :[[@LINE+3]]:3: warning: use `std::max` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: obj.member1 = std::max(obj.member1, obj.member2);
+  MyClass obj;
+  if (obj.member1 < obj.member2)
+    obj.member1 = obj.member2; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: obj.member2 = std::min(obj.member1, obj.member2);
+  if (obj.member1 < obj.member2)
+    obj.member2 = obj.member1; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `>` [readability-use-std-min-max]
+  // CHECK-FIXES: obj.member2 = std::min(obj.member2, obj.member1);
+  if (obj.member2 > obj.member1)
+    obj.member2 = obj.member1; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `>` [readability-use-std-min-max]
+  // CHECK-FIXES: obj.member1 = std::max(obj.member2, obj.member1);
+  if (obj.member2 > obj.member1)
+    obj.member1 = obj.member2; 
+  
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: obj.member1 = std::max<int>(obj.member1, value4);
+  if (obj.member1 < value4)
+    obj.member1 = value4; 
+  
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value3 = std::min(obj.member1 + value2, value3);
+  if (obj.member1 + value2 < value3)
+    value3 = obj.member1 + value2; 
+  
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `<=` [readability-use-std-min-max]
+  // CHECK-FIXES: obj.member2 = std::min(value1, obj.member2);
+  if (value1 <= obj.member2)
+    obj.member2 = value1; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `<=` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max(value1, obj.member2);
+  if (value1 <= obj.member2)
+    value1 = obj.member2; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `>=` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max(obj.member2, value1);
+  if (obj.member2 >= value1)
+    value1 = obj.member2; 
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::min` instead of `>=` [readability-use-std-min-max]
+  // CHECK-FIXES: obj.member2 = std::min(obj.member2, value1);
+  if (obj.member2 >= value1)
+    obj.member2 = value1; 
+  
+  // No suggestion needed here
+  if (MY_MACRO_MIN(value1, value2) < value3)
+    value3 = MY_MACRO_MIN(value1, value2); 
+  
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value4 = std::max<int>(value4, value2);
+  if (value4 < value2){
+    value4 = value2; 
+  }
+
+  // No suggestion needed here
+  if(value1 < value2)
+    value2 = value1;
+  else
+    value2 = value3;
+  
+  // No suggestion needed here
+  if(value1<value2){
+    value2 = value1; 
+  }
+  else{
+    value2 = value3;  
+  }
+
+  // No suggestion needed here
+  if(value1<value2){
+    value2 = value1; 
+    int res = value1 + value2;
+  }
+
+  // No suggestion needed here
+  MY_IF_MACRO(value1 < value2, value1 = value2;)
+
+  // No suggestion needed here
+  if(value1<value2){
+    value1 = value2;
+  }
+  else if(value1>value2){
+    value2 = value1;
+  }
+
+  // CHECK-MESSAGES: :[[@LINE+3]]:5: warning: use `std::max` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max(value1, value3);
+  if(value1 == value2){
+    if(value1<value3)
+      value1 = value3;
+  }
+
+  // CHECK-MESSAGES: :[[@LINE+5]]:7: warning: use `std::max` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value1 = std::max<int>(value1, value4);
+  if(value1 == value2){
+    if(value2 == value3){
+      value3+=1;
+      if(value1<value4){
+        value1 = value4;
+      }
+    }
+    else if(value3>value2){
+      value2 = value3;
+    }
+  }
+  
+  // CHECK-MESSAGES: :[[@LINE+4]]:3: warning: use `std::min` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value6 = std::min<unsigned int>(value5, value6);
+  unsigned int value5;
+  unsigned char value6;
+  if(value5<value6){
+    value6 = value5;
+  }
+
+  //No suggestion needed here
+  if(value7<value6){
+    value6 = value7;
+  }
+
+  //CHECK-MESSAGES: :[[@LINE+3]]:3: warning: use `std::min` instead of `<` [readability-use-std-min-max]
+  //CHECK-FIXES: value1 = std::min(value8, value1);
+  const int value8 = 5;
+  if(value8<value1)
+    value1 = value8;
+  
+  //CHECK-MESSAGES: :[[@LINE+3]]:3: warning: use `std::min` instead of `<` [readability-use-std-min-max]
+  //CHECK-FIXES: value1 = std::min(value9, value1);
+  volatile int value9 = 6;
+  if(value9<value1)
+    value1 = value9;
+}
+
+using my_size = unsigned long long;
+
+template<typename T>
+struct MyVector
+{
+    using size_type = my_size;
+    size_type size() const;
+};
+
+void testVectorSizeType() {
+  MyVector<int> v;
+  unsigned int value;
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `>` [readability-use-std-min-max]
+  // CHECK-FIXES: value = std::max<my_size>(v.size(), value);
+  if (v.size() > value)
+    value = v.size();
+
+  // CHECK-MESSAGES: :[[@LINE+2]]:3: warning: use `std::max` instead of `<` [readability-use-std-min-max]
+  // CHECK-FIXES: value = std::max<my_size>(value, v.size());
+  if (value < v.size())
+    value = v.size();
+}