[llvm] Reland "[Transforms] LoopIdiomRecognize recognize strlen and wcslen (#108985)" (PR #131412)

[Henry Jiang via llvm-commits]

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@@ -126,6 +127,27 @@ static cl::opt<bool, true>
                       cl::location(DisableLIRP::Memcpy), cl::init(false),
                       cl::ReallyHidden);
 
+bool DisableLIRP::Strlen;
+static cl::opt<bool, true>
+    DisableLIRPStrlen("disable-loop-idiom-strlen",
+                      cl::desc("Proceed with loop idiom recognize pass, but do "
+                               "not convert loop(s) to strlen."),
+                      cl::location(DisableLIRP::Strlen), cl::init(false),
+                      cl::ReallyHidden);
+
+/// Some target libraries have a significant call overhead for `wcslen`,
+/// which can degrade performance when the input string is not long enough
+/// to justify the cost. To avoid unnecessary performance penalties,
+/// we disable it by default.
+bool DisableLIRP::Wcslen;
+static cl::opt<bool, true> EnableLIRPWcslen(
+    "enable-loop-idiom-wcslen",
+    cl::desc("Proceed with loop idiom recognize pass, "
+             "enable conversion of loop(s) to wcslen."),
+    cl::location(DisableLIRP::Wcslen), cl::init(true),
+    cl::callback([](const bool &) { DisableLIRP::Wcslen = false; }),
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mustartt wrote:

yes I inverted the conditions how the flag is `-disable-loop-idiom-wcslen`

https://github.com/llvm/llvm-project/pull/131412