diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -456,9 +456,18 @@
 option(LLVM_ENABLE_LIBCXX "Use libc++ if available." OFF)
 option(LLVM_STATIC_LINK_CXX_STDLIB "Statically link the standard library." OFF)
 option(LLVM_ENABLE_LLD "Use lld as C and C++ linker." OFF)
-option(LLVM_ENABLE_PEDANTIC "Compile with pedantic enabled." ON)
 option(LLVM_ENABLE_WERROR "Fail and stop if a warning is triggered." OFF)
 
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+  # -pedantic may warn on extensions from newer standards that are widely ported
+  # to older language modes. They are usually of lower value and cannot be
+  # suppressed by pragma ( https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90843),
+  # so we just disable -pedantic by default.
+  option(LLVM_ENABLE_PEDANTIC "Compile with pedantic enabled" OFF)
+else()
+  option(LLVM_ENABLE_PEDANTIC "Compile with pedantic enabled" ON)
+endif()
+
 option(LLVM_ENABLE_DUMP "Enable dump functions even when assertions are disabled" OFF)
 
 if( NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG" )