-Revert parts of 84326 and 84411. Distinquishing between fixed and non-fixed

stack slots and giving them different PseudoSourceValue's did not fix the
problem of post-alloc scheduling miscompiling llvm itself.
- Apply Dan's conservative workaround by assuming any non fixed stack slots can
alias other memory locations. This means a load from spill slot #1 cannot 
move above a store of spill slot #2. 
- Enable post-alloc scheduling for x86 at optimization leverl Default and above.

llvm-svn: 84424

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Target/X86/X86Subtarget.h b/llvm/lib/Target/X86/X86Subtarget.h
index 16a2f1023c9..e9392f5b36f 100644
--- a/llvm/lib/Target/X86/X86Subtarget.h
+++ b/llvm/lib/Target/X86/X86Subtarget.h
@@ -220,7 +220,7 @@ public:
   /// at 'More' optimization level.
   bool enablePostRAScheduler(CodeGenOpt::Level OptLevel) const {
     // FIXME: This causes llvm to miscompile itself on i386. :-(
-    return false/*OptLevel >= CodeGenOpt::Default*/;
+    return OptLevel >= CodeGenOpt::Default;
   }
 };