diff --git a/cmake/tools/SetupLLVM.cmake b/cmake/tools/SetupLLVM.cmake
index c695a4175e..d1b462701a 100644
--- a/cmake/tools/SetupLLVM.cmake
+++ b/cmake/tools/SetupLLVM.cmake
@@ -1,4 +1,3 @@
-
 set(DEFAULT_ENABLE_LLVM ON)
 
 # if target is bun-zig, set ENABLE_LLVM to OFF
@@ -12,7 +11,13 @@ if(NOT ENABLE_LLVM)
   return()
 endif()
 
-set(DEFAULT_LLVM_VERSION "21.1.8")
+# LLVM 21 is required for Windows ARM64 (first version with ARM64 Windows builds)
+# Other platforms use LLVM 19.1.7
+if(WIN32 AND CMAKE_SYSTEM_PROCESSOR MATCHES "ARM64|aarch64|AARCH64")
+  set(DEFAULT_LLVM_VERSION "21.1.8")
+else()
+  set(DEFAULT_LLVM_VERSION "19.1.7")
+endif()
 
 optionx(LLVM_VERSION STRING "The version of LLVM to use" DEFAULT ${DEFAULT_LLVM_VERSION})
 
@@ -72,12 +77,14 @@ macro(find_llvm_command variable command)
     )
   endif()
 
+  math(EXPR LLVM_VERSION_NEXT_MAJOR "${LLVM_VERSION_MAJOR} + 1")
+
   find_command(
     VARIABLE ${variable}
     VERSION_VARIABLE LLVM_VERSION
     COMMAND ${commands}
     PATHS ${LLVM_PATHS}
-    VERSION "${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}"
+    VERSION ">=${LLVM_VERSION_MAJOR}.1.0 <${LLVM_VERSION_NEXT_MAJOR}.0.0"
   )
   list(APPEND CMAKE_ARGS -D${variable}=${${variable}})
 endmacro()
diff --git a/src/bun.js/bindings/EncodingTables.h b/src/bun.js/bindings/EncodingTables.h
index ca3d1d7e7a..a7b7dec52a 100644
--- a/src/bun.js/bindings/EncodingTables.h
+++ b/src/bun.js/bindings/EncodingTables.h
@@ -55,10 +55,6 @@ template<typename CollectionType, typename KeyType> static auto findInSortedPair
 inline void checkEncodingTableInvariants() {}
 #endif
 
-// LLVM 21+ -Wcharacter-conversion flags intentional char32_t/char16_t comparisons
-// used for Unicode code point range checks in findFirstInSortedPairs.
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wcharacter-conversion"
 struct CompareFirst {
     template<typename TypeA, typename TypeB> bool operator()(const TypeA& a, const TypeB& b)
     {
@@ -136,6 +132,5 @@ template<typename CollectionType, typename KeyType> static auto findInSortedPair
     }
     return std::ranges::equal_range(collection, makeFirstAdapter(key), CompareFirst {});
 }
-#pragma clang diagnostic pop
 
 }