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

[Piotr Zegar via cfe-commits]

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@@ -0,0 +1,27 @@
+// RUN: %check_clang_tidy %s readability-ConditionalToStdMinMax %t
+
+void foo() {
+  int value1,value2;
+
+  // CHECK-MESSAGES: :[[@LINE+1]]:3: warning: use std::max instead of < [readability-ConditionalToStdMinMax]
+  if (value1 < value2)
+    value1 = value2; // CHECK-FIXES: value1 = std::max(value1, value2);
+
+  // CHECK-MESSAGES: :[[@LINE+1]]:3: warning: use std::min instead of < [readability-ConditionalToStdMinMax]
+  if (value1 < value2)
+    value2 = value1; // CHECK-FIXES: value2 = std::min(value1, value2);
+
+  // CHECK-MESSAGES: :[[@LINE+1]]:3: warning: use std::min instead of > [readability-ConditionalToStdMinMax]
+  if (value2 > value1)
+    value2 = value1; // CHECK-FIXES: value2 = std::min(value2, value1);
+
+  // CHECK-MESSAGES: :[[@LINE+1]]:3: warning: use std::max instead of > [readability-ConditionalToStdMinMax]
+  if (value2 > value1)
+    value1 = value2; // CHECK-FIXES: value1 = std::max(value2, value1);
+
+  // No suggestion needed here
+  if (value1 == value2)
+    value1 = value2;
+
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PiotrZSL wrote:

Add test when value1 is int, but value2 is short, std::min/max may not work properly in such case and template argument may need to be passed explicitly.

https://github.com/llvm/llvm-project/pull/77816