Rewrite ``asm("":::"memory")`` to ``fence seq_cst``

This is often used as a compiler barrier and should "just work" in user code.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=2345
R=eliben@chromium.org
TEST=  (cd ./pnacl/build/llvm_x86_64 && ninja check-all)

Review URL: https://codereview.chromium.org/21178002

1 files changed, 1 insertions, 0 deletions

diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index a9c19a33dc..5682a55909 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -626,6 +626,7 @@ int main(int argc, char **argv) {
   initializeReplacePtrsWithIntsPass(Registry);
   initializeResolveAliasesPass(Registry);
   initializeResolvePNaClIntrinsicsPass(Registry);
+  initializeRewriteAsmDirectivesPass(Registry);
   initializeRewriteAtomicsPass(Registry);
   initializeRewriteLLVMIntrinsicsPass(Registry);
   initializeRewritePNaClLibraryCallsPass(Registry);