reapply the patch reverted in r116033:

"Reimplement (part of) the or -> add optimization.  Matching 'or' into 'add'"

With a critical fix: the add pseudos clobber EFLAGS.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116039 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 14 deletions

diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index c1e15e4..3f420f5 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -544,20 +544,6 @@ def trunc_su : PatFrag<(ops node:$src), (trunc node:$src), [{
   return N->hasOneUse();
 }]>;
 
-// Treat an 'or' node is as an 'add' if the or'ed bits are known to be zero.
-def or_is_add : PatFrag<(ops node:$lhs, node:$rhs), (or node:$lhs, node:$rhs),[{
-  if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N->getOperand(1)))
-    return CurDAG->MaskedValueIsZero(N->getOperand(0), CN->getAPIntValue());
-
-  unsigned BitWidth = N->getValueType(0).getScalarType().getSizeInBits();
-  APInt Mask = APInt::getAllOnesValue(BitWidth);
-  APInt KnownZero0, KnownOne0;
-  CurDAG->ComputeMaskedBits(N->getOperand(0), Mask, KnownZero0, KnownOne0, 0);
-  APInt KnownZero1, KnownOne1;
-  CurDAG->ComputeMaskedBits(N->getOperand(1), Mask, KnownZero1, KnownOne1, 0);
-  return (~KnownZero0 & ~KnownZero1) == 0;
-}]>;
-
 //===----------------------------------------------------------------------===//
 // Instruction list.
 //