Back out r160101 and instead implement a dag combine to recover from instcombine transformation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160387 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 7 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 0a62242436..125c74a89a 100644
--- a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -40,13 +40,6 @@ static bool ShrinkDemandedConstant(Instruction *I, unsigned OpNo,
 
   // This instruction is producing bits that are not demanded. Shrink the RHS.
   Demanded &= OpC->getValue();
-  if (I->getOpcode() == Instruction::Add) {
-    // However, if the instruction is an add then the constant may be negated
-    // when the opcode is changed to sub. Check if the transformation is really
-    // shrinking the constant.
-    if (Demanded.abs().getActiveBits() > OpC->getValue().abs().getActiveBits())
-      return false;
-  }
   I->setOperand(OpNo, ConstantInt::get(OpC->getType(), Demanded));
   return true;
 }