Remove unused ShouldFoldAtomicFences flag.

I think it's almost impossible to fold atomic fences profitably under
LLVM/C++11 semantics. As a result, this is now unused and just
cluttering up the target interface.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179940 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 7 deletions

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 94370ae4ee..b7ba0b8188 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -528,13 +528,6 @@ void X86TargetLowering::resetOperationActions() {
 
   setOperationAction(ISD::ATOMIC_FENCE  , MVT::Other, Custom);
 
-  // On X86 and X86-64, atomic operations are lowered to locked instructions.
-  // Locked instructions, in turn, have implicit fence semantics (all memory
-  // operations are flushed before issuing the locked instruction, and they
-  // are not buffered), so we can fold away the common pattern of
-  // fence-atomic-fence.
-  setShouldFoldAtomicFences(true);
-
   // Expand certain atomics
   for (unsigned i = 0; i != array_lengthof(IntVTs); ++i) {
     MVT VT = IntVTs[i];