diff --git a/src/clangsa/GCChecker.cpp b/src/clangsa/GCChecker.cpp
index 9caff014c7703a..ecaeb460ebf914 100644
--- a/src/clangsa/GCChecker.cpp
+++ b/src/clangsa/GCChecker.cpp
@@ -767,7 +767,7 @@ bool GCChecker::isFDAnnotatedNotSafepoint(const clang::FunctionDecl *FD, const S
   SourceLocation Loc = FD->getLocation();
   StringRef Name = SM.getFilename(Loc);
   Name = llvm::sys::path::filename(Name);
-  if (Name.startswith("llvm-"))
+  if (Name.starts_with("llvm-"))
       return true;
   return false;
 }
@@ -911,9 +911,9 @@ bool GCChecker::isSafepoint(const CallEvent &Call, CheckerContext &C) const {
       if (FD->getBuiltinID() != 0 || FD->isTrivial())
         isCalleeSafepoint = false;
       else if (FD->getDeclName().isIdentifier() &&
-               (FD->getName().startswith("uv_") ||
-                FD->getName().startswith("unw_") ||
-                FD->getName().startswith("_U")) &&
+               (FD->getName().starts_with("uv_") ||
+                FD->getName().starts_with("unw_") ||
+                FD->getName().starts_with("_U")) &&
                FD->getName() != "uv_run")
         isCalleeSafepoint = false;
       else
@@ -1050,13 +1050,13 @@ bool GCChecker::processAllocationOfResult(const CallEvent &Call,
         // global roots.
         StringRef FDName =
             FD->getDeclName().isIdentifier() ? FD->getName() : "";
-        if (FDName.startswith("jl_box_") || FDName.startswith("ijl_box_")) {
+        if (FDName.starts_with("jl_box_") || FDName.starts_with("ijl_box_")) {
           SVal Arg = Call.getArgSVal(0);
           if (auto CI = Arg.getAs<nonloc::ConcreteInt>()) {
             const llvm::APSInt &Value = CI->getValue();
             bool GloballyRooted = false;
             const int64_t NBOX_C = 1024;
-            if (FDName.startswith("jl_box_u") || FDName.startswith("ijl_box_u")) {
+            if (FDName.starts_with("jl_box_u") || FDName.starts_with("ijl_box_u")) {
               if (Value < NBOX_C) {
                 GloballyRooted = true;
               }
diff --git a/src/codegen.cpp b/src/codegen.cpp
index ebc5d136939733..9bb80eaf8f0516 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -2179,7 +2179,7 @@ static GlobalVariable *get_pointer_to_constant(jl_codegen_params_t &emission_con
             gv = get_gv(gvname);
         }
     }
-    assert(gv->getName().startswith(name.str()));
+    assert(gv->getName().starts_with(name.str()));
     assert(val == gv->getInitializer());
     return gv;
 }
@@ -8866,7 +8866,7 @@ static jl_llvm_functions_t
                 !jl_is_submodule(mod, jl_core_module));
     };
     auto in_tracked_path = [] (StringRef file) { // falls within an explicitly set file or directory
-        return jl_options.tracked_path != NULL && file.startswith(jl_options.tracked_path);
+        return jl_options.tracked_path != NULL && file.starts_with(jl_options.tracked_path);
     };
     bool mod_is_user_mod = in_user_mod(ctx.module);
     bool mod_is_tracked = in_tracked_path(ctx.file);
@@ -9661,7 +9661,7 @@ static jl_llvm_functions_t
                     // make sure that anything we attempt to call has some inlining info, just in case optimization messed up
                     // (except if we know that it is an intrinsic used in our prologue, which should never have its own debug subprogram)
                     Function *F = call->getCalledFunction();
-                    if (!in_prologue || !F || !(F->isIntrinsic() || F->getName().startswith("julia.") || &I == restTuple)) {
+                    if (!in_prologue || !F || !(F->isIntrinsic() || F->getName().starts_with("julia.") || &I == restTuple)) {
                         I.setDebugLoc(topdebugloc);
                     }
                 }
diff --git a/src/coverage.cpp b/src/coverage.cpp
index c061276e66fd90..685370198ff13e 100644
--- a/src/coverage.cpp
+++ b/src/coverage.cpp
@@ -207,7 +207,7 @@ extern "C" JL_DLLEXPORT void jl_write_coverage_data(const char *output)
 {
     if (output) {
         StringRef output_pattern(output);
-        if (output_pattern.endswith(".info"))
+        if (output_pattern.ends_with(".info"))
             write_lcov_data(coverageData, jl_format_filename(output_pattern.str().c_str()));
     }
     else {
diff --git a/src/jitlayers.cpp b/src/jitlayers.cpp
index b60a0857dbf093..4b507f60359ac9 100644
--- a/src/jitlayers.cpp
+++ b/src/jitlayers.cpp
@@ -609,7 +609,7 @@ static Expected<orc::ThreadSafeModule> validateExternRelocations(orc::ThreadSafe
         auto F = dyn_cast<Function>(&GO);
         if (!F)
             return false;
-        return F->isIntrinsic() || F->getName().startswith("julia.");
+        return F->isIntrinsic() || F->getName().starts_with("julia.");
     };
     // validate the relocations for M (only for RuntimeDyld, JITLink performs its own symbol validation)
     auto Err = TSM.withModuleDo([isIntrinsicFunction](Module &M) JL_NOTSAFEPOINT {
@@ -1209,7 +1209,7 @@ namespace {
                 {
                     if (*jl_ExecutionEngine->get_dump_llvm_opt_stream()) {
                         for (auto &F : M.functions()) {
-                            if (F.isDeclaration() || F.getName().startswith("jfptr_")) {
+                            if (F.isDeclaration() || F.getName().starts_with("jfptr_")) {
                                 continue;
                             }
                             // Each function is printed as a YAML object with several attributes
@@ -1262,7 +1262,7 @@ namespace {
                         // Print LLVM function statistics _after_ optimization
                         ios_printf(stream, "  after: \n");
                         for (auto &F : M.functions()) {
-                            if (F.isDeclaration() || F.getName().startswith("jfptr_")) {
+                            if (F.isDeclaration() || F.getName().starts_with("jfptr_")) {
                                 continue;
                             }
                             Stat(F).dump(stream);
@@ -1449,7 +1449,7 @@ struct JuliaOJIT::DLSymOptimizer {
     void operator()(Module &M) {
         for (auto &GV : M.globals()) {
             auto Name = GV.getName();
-            if (Name.startswith("jlplt") && Name.endswith("got")) {
+            if (Name.starts_with("jlplt") && Name.ends_with("got")) {
                 auto fname = GV.getAttribute("julia.fname").getValueAsString().str();
                 void *addr;
                 if (GV.hasAttribute("julia.libname")) {
@@ -1702,7 +1702,7 @@ JuliaOJIT::JuliaOJIT()
                   DL.getGlobalPrefix(),
                   [&](const orc::SymbolStringPtr &S) {
                         const char *const atomic_prefix = "__atomic_";
-                        return (*S).startswith(atomic_prefix);
+                        return (*S).starts_with(atomic_prefix);
                   })));
         }
     }
diff --git a/src/llvm-cpufeatures.cpp b/src/llvm-cpufeatures.cpp
index 2539c5cd2e37ca..05d62adc57926f 100644
--- a/src/llvm-cpufeatures.cpp
+++ b/src/llvm-cpufeatures.cpp
@@ -94,7 +94,7 @@ bool lowerCPUFeatures(Module &M) JL_NOTSAFEPOINT
     for (auto &F: M.functions()) {
         auto FN = F.getName();
 
-        if (FN.startswith("julia.cpu.have_fma.")) {
+        if (FN.starts_with("julia.cpu.have_fma.")) {
             for (Use &U: F.uses()) {
                 User *RU = U.getUser();
                 CallInst *I = cast<CallInst>(RU);
diff --git a/src/llvm-multiversioning.cpp b/src/llvm-multiversioning.cpp
index 65fbcd3e0861cf..dc5427c2520947 100644
--- a/src/llvm-multiversioning.cpp
+++ b/src/llvm-multiversioning.cpp
@@ -100,11 +100,11 @@ static uint32_t collect_func_info(Function &F, const Triple &TT, bool &has_vecca
                 }
                 if (auto callee = call->getCalledFunction()) {
                     auto name = callee->getName();
-                    if (name.startswith("llvm.muladd.") || name.startswith("llvm.fma.")) {
+                    if (name.starts_with("llvm.muladd.") || name.starts_with("llvm.fma.")) {
                         flag |= JL_TARGET_CLONE_MATH;
                     }
-                    else if (name.startswith("julia.cpu.")) {
-                        if (name.startswith("julia.cpu.have_fma.")) {
+                    else if (name.starts_with("julia.cpu.")) {
+                        if (name.starts_with("julia.cpu.have_fma.")) {
                             // for some platforms we know they always do (or don't) support
                             // FMA. in those cases we don't need to clone the function.
                             // always_have_fma returns an optional<bool>
diff --git a/src/llvm-simdloop.cpp b/src/llvm-simdloop.cpp
index f29802b438e1e9..07afa8c930deb4 100644
--- a/src/llvm-simdloop.cpp
+++ b/src/llvm-simdloop.cpp
@@ -177,7 +177,7 @@ static bool processLoop(Loop &L, OptimizationRemarkEmitter &ORE, ScalarEvolution
         const MDString *S = dyn_cast<MDString>(Op);
         if (S) {
             LLVM_DEBUG(dbgs() << "LSL: found " << S->getString() << "\n");
-            if (S->getString().startswith("julia")) {
+            if (S->getString().starts_with("julia")) {
                 if (S->getString().equals("julia.simdloop"))
                     simd = true;
                 if (S->getString().equals("julia.ivdep"))
diff --git a/src/processor_arm.cpp b/src/processor_arm.cpp
index 1852188c718a9e..47e774418518d3 100644
--- a/src/processor_arm.cpp
+++ b/src/processor_arm.cpp
@@ -830,7 +830,7 @@ template<typename T, typename F>
 static inline bool try_read_procfs_line(llvm::StringRef line, const char *prefix, T &out,
                                         bool &flag, F &&reset)
 {
-    if (!line.startswith(prefix))
+    if (!line.starts_with(prefix))
         return false;
     if (flag)
         reset();