- Remove the buggy -X/C -> X/-C transform. This isn't valid when X isn't a

  constant. If X is a constant, then this is folded elsewhere.

- Added a note to Target/README.txt to indicate that we'd like to implement
  this when we're able.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60399 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 12 deletions

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 7ad75d2..34c5fb3 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -2929,18 +2929,6 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
     // sdiv X, -1 == -X
     if (RHS->isAllOnesValue())
       return BinaryOperator::CreateNeg(Op0);
-
-    // -X/C -> X/-C, if and only if negation doesn't overflow.
-    if (Value *LHSNeg = dyn_castNegVal(Op0)) {
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(LHSNeg)) {
-        Constant *RHSNeg = ConstantExpr::getNeg(RHS);
-        if (RHS != RHSNeg) {    // Check that there is no overflow.
-          Constant *CINeg = ConstantExpr::getNeg(CI);
-          if (CI != CINeg)      // Check that there is no overflow.
-            return BinaryOperator::CreateSDiv(LHSNeg, RHSNeg);
-        }
-      }
-    }
   }
 
   // If the sign bits of both operands are zero (i.e. we can prove they are