From 507834726d401eeabb6bbd354e069bbab32c4b22 Mon Sep 17 00:00:00 2001
From: Shawn Walker-Salas <shawn.walker@oracle.com>
Date: Tue, 21 Feb 2017 10:06:07 -0800
Subject: [PATCH] use -O0 when building release LLVM on sparc

The bits produced by gcc above -O0 when building rust's private copy of llvm on
sparc result in either versions of llvm-tblgen that consistently segfault or
produce otherwise unuseable code.  This does not affect cross-compiles for some
reason.  Investigation with gcc upstream is in progress.
---
 CMakeLists.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9819389141f7..90a3d10491a1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -698,6 +698,12 @@ if( MINGW )
   llvm_replace_compiler_option(CMAKE_CXX_FLAGS_RELEASE "-O3" "-O2")
 endif()
 
+if( "${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU" AND "${LLVM_NATIVE_ARCH}" MATCHES "Sparc" )
+  # gcc 4.x, 5.x (at least) generate bad code on sparc above -O0 when compiling
+  # llvm; notably llvm-tblgen consistently core dumps.
+  llvm_replace_compiler_option(CMAKE_CXX_FLAGS_RELEASE "-O3" "-O0")
+endif()
+
 # Put this before tblgen. Else we have a circular dependence.
 add_subdirectory(lib/Support)
 add_subdirectory(lib/TableGen)