[X86] Disable FixupSetCC for CodeGenOpt::None

It is an optimization pass, and should not run at -O0. Especially since Fast RA
will not do the required register coalescing anyway, so it's a loss even from
the optimization standpoint.

This also works around (but doesn't quite fix) PR28489.

llvm-svn: 275099
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index f9d2d0a..445adbd 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -304,10 +304,10 @@
 }
 
 void X86PassConfig::addPreRegAlloc() {
-  addPass(createX86FixupSetCC());
-
-  if (getOptLevel() != CodeGenOpt::None)
-    addPass(createX86OptimizeLEAs());
+  if (getOptLevel() != CodeGenOpt::None) {
+    addPass(createX86FixupSetCC());    
+    addPass(createX86OptimizeLEAs());    
+  }
 
   addPass(createX86CallFrameOptimization());
   addPass(createX86WinAllocaExpander());