Revert "GVN-hoist: enable by default" & "Make GVN Hoisting obey optnone/bisect."

This reverts commits r277685 & r277688. r277685 broke compiler-rt
compilation http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA_build/23335
and r277685 is a followup from it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277690 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/IPO/PassManagerBuilder.cpp

@@ -138,8 +138,8 @@ static cl::opt<int> PreInlineThreshold(
              "(default = 75)"));
 
 static cl::opt<bool> EnableGVNHoist(
-    "enable-gvn-hoist", cl::init(true), cl::Hidden,
-    cl::desc("Enable the GVN hoisting pass (default = on)"));
+    "enable-gvn-hoist", cl::init(false), cl::Hidden,
+    cl::desc("Enable the experimental GVN Hoisting pass"));
 
 PassManagerBuilder::PassManagerBuilder() {
     OptLevel = 2;

test/Feature/optnone-opt.ll

@@ -41,7 +41,6 @@ attributes #0 = { optnone noinline }
 ; OPT-O1-DAG: Skipping pass 'Combine redundant instructions'
 ; OPT-O1-DAG: Skipping pass 'Dead Store Elimination'
 ; OPT-O1-DAG: Skipping pass 'Early CSE'
-; OPT-O1-DAG: Skipping pass 'Early GVN Hoisting of Expressions'
 ; OPT-O1-DAG: Skipping pass 'Jump Threading'
 ; OPT-O1-DAG: Skipping pass 'MemCpy Optimization'
 ; OPT-O1-DAG: Skipping pass 'Reassociate expressions'