diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -12,6 +12,7 @@
 include(CheckCXXCompilerFlag)
 include(CheckSymbolExists)
 include(CMakeDependentOption)
+include(LLVMProcessSources)
 
 if(CMAKE_LINKER MATCHES "lld-link" OR (MSVC AND (LLVM_USE_LINKER STREQUAL "lld" OR LLVM_ENABLE_LLD)))
   set(LINKER_IS_LLD_LINK TRUE)
@@ -296,6 +297,14 @@
          NOT Uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
     add_flag_or_print_warning("-fno-shrink-wrap" FNO_SHRINK_WRAP)
   endif()
+  # When g++ builds with -O3 -fPIC on Solaris/sparcv9, executables created
+  # with the system linker SEGV.
+  if(CMAKE_COMPILER_IS_GNUCXX AND
+     ${CMAKE_SYSTEM_NAME} STREQUAL "SunOS" AND
+     LLVM_NATIVE_ARCH STREQUAL "Sparc" AND
+     NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
+     llvm_replace_compiler_option(CMAKE_CXX_FLAGS_RELEASE "-O3" "-O")
+  endif()
 endif()
 
 if(NOT WIN32 AND NOT CYGWIN AND NOT (${CMAKE_SYSTEM_NAME} MATCHES "AIX" AND CMAKE_CXX_COMPILER_ID STREQUAL "GNU"))