From: Oscar Fuentes <ofv@wanadoo.es>
Date: Fri, 7 Jan 2011 20:31:03 +0000 (+0000)
Subject: Don't use -O3 on Mingw, as people report it as unreliable. Use -O2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=53bf3ee82ba9fb6e6008b9752d4f8f4e71a4bfe4;p=oota-llvm.git

Don't use -O3 on Mingw, as people report it as unreliable. Use -O2
instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123028 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3f48b58f438..5e27c6f82e4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -317,6 +317,12 @@ if( MINGW )
   set(CMAKE_C_STANDARD_LIBRARIES "${CMAKE_C_STANDARD_LIBRARIES}${LLVM_SYSTEM_LIBS}")
 endif()
 
+if( MINGW )
+  # People report that -O3 is unreliable on MinGW. The traditional
+  # build also uses -O2 for that reason:
+  llvm_replace_compiler_option(CMAKE_CXX_FLAGS_RELEASE "-O3" "-O2")
+endif()
+
 add_subdirectory(lib/Support)
 
 # Everything else depends on Support:
diff --git a/cmake/modules/LLVMProcessSources.cmake b/cmake/modules/LLVMProcessSources.cmake
index 5f59eac4511..98b61296db4 100644
--- a/cmake/modules/LLVMProcessSources.cmake
+++ b/cmake/modules/LLVMProcessSources.cmake
@@ -1,5 +1,15 @@
 include(AddFileDependencies)
 
+macro(llvm_replace_compiler_option var old new)
+  # Replaces a compiler option or switch `old' in `var' by `new'.
+  # If `old' is not in `var', appends `new' to `var'.
+  # Example: llvm_replace_compiler_option(CMAKE_CXX_FLAGS_RELEASE "-O3" "-O2")
+  if( "${${var}}" MATCHES "(^| )${old}($| )" )
+    string( REGEX REPLACE "(^| )${old}($| )" " ${new}  " ${var} "${${var}}" )
+  else()
+    set( ${var} "${${var}} ${new}" )
+  endif()
+endmacro(llvm_replace_compiler_option)
 
 macro(add_td_sources srcs)
   file(GLOB tds *.td)