[llvm] [llvm] Use StringRef::drop_back (NFC) (PR #139471)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-hexagon

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/139471.diff


3 Files Affected:

- (modified) llvm/include/llvm/IR/Constants.h (+1-1) 
- (modified) llvm/lib/Support/CommandLine.cpp (+1-1) 
- (modified) llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp (+2-3) 


``````````diff
diff --git a/llvm/include/llvm/IR/Constants.h b/llvm/include/llvm/IR/Constants.h
index 76efa9bd63522..7137c699cc992 100644
--- a/llvm/include/llvm/IR/Constants.h
+++ b/llvm/include/llvm/IR/Constants.h
@@ -672,7 +672,7 @@ class ConstantDataSequential : public ConstantData {
   StringRef getAsCString() const {
     assert(isCString() && "Isn't a C string");
     StringRef Str = getAsString();
-    return Str.substr(0, Str.size() - 1);
+    return Str.drop_back();
   }
 
   /// Return the raw, underlying, bytes of this data. Note that this is an
diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index f1dd39ce133a8..a407be929af85 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -726,7 +726,7 @@ static Option *getOptionPred(StringRef Name, size_t &Length,
   // characters in it (so that the next iteration will not be the empty
   // string.
   while (OMI == OptionsMap.end() && Name.size() > 1) {
-    Name = Name.substr(0, Name.size() - 1); // Chop off the last character.
+    Name = Name.drop_back();
     OMI = OptionsMap.find(Name);
     if (OMI != OptionsMap.end() && !Pred(OMI->getValue()))
       OMI = OptionsMap.end();
diff --git a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp
index 7f8315529e675..91051cd4e2d51 100644
--- a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp
+++ b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp
@@ -644,9 +644,8 @@ MCSubtargetInfo *Hexagon_MC::createHexagonMCSubtargetInfo(const Triple &TT,
 void Hexagon_MC::addArchSubtarget(MCSubtargetInfo const *STI, StringRef FS) {
   assert(STI != nullptr);
   if (STI->getCPU().contains("t")) {
-    auto ArchSTI = createHexagonMCSubtargetInfo(
-        STI->getTargetTriple(),
-        STI->getCPU().substr(0, STI->getCPU().size() - 1), FS);
+    auto ArchSTI = createHexagonMCSubtargetInfo(STI->getTargetTriple(),
+                                                STI->getCPU().drop_back(), FS);
     std::lock_guard<std::mutex> Lock(ArchSubtargetMutex);
     ArchSubtarget[std::string(STI->getCPU())] =
         std::unique_ptr<MCSubtargetInfo const>(ArchSTI);

``````````

</details>


https://github.com/llvm/llvm-project/pull/139471