Revert two GEP-related InstCombine commits

This reverts commit r216523 and r216598; people have reported
regressions.

llvm-svn: 216698

1 files changed, 11 insertions, 40 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 2f80e8389d9..f01dca7fab8 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1508,48 +1508,19 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
         GetElementPtrInst::Create(Src->getOperand(0), Indices, GEP.getName());
   }
 
-  if (DL && GEP.getNumIndices() == 1) {
+  // Canonicalize (gep i8* X, -(ptrtoint Y)) to (sub (ptrtoint X), (ptrtoint Y))
+  // The GEP pattern is emitted by the SCEV expander for certain kinds of
+  // pointer arithmetic.
+  if (DL && GEP.getNumIndices() == 1 &&
+      match(GEP.getOperand(1), m_Neg(m_PtrToInt(m_Value())))) {
     unsigned AS = GEP.getPointerAddressSpace();
-    if (GEP.getOperand(1)->getType()->getScalarSizeInBits() ==
+    if (GEP.getType() == Builder->getInt8PtrTy(AS) &&
+        GEP.getOperand(1)->getType()->getScalarSizeInBits() ==
         DL->getPointerSizeInBits(AS)) {
-      Type *PtrTy = GEP.getPointerOperandType();
-      Type *Ty = PtrTy->getPointerElementType();
-      uint64_t TyAllocSize = DL->getTypeAllocSize(Ty);
-
-      uint64_t C;
-      Value *V = nullptr;
-      if (TyAllocSize == 1) {
-          V = GEP.getOperand(1);
-      } else if (match(GEP.getOperand(1),
-                       m_AShr(m_Value(V), m_ConstantInt(C)))) {
-        if (TyAllocSize != 1ULL << C)
-          V = nullptr;
-      } else if (match(GEP.getOperand(1),
-                       m_SDiv(m_Value(V), m_ConstantInt(C)))) {
-        if (TyAllocSize != C)
-          V = nullptr;
-      }
-
-      if (V) {
-        // Canonicalize (gep i8* X, -(ptrtoint Y))
-        // to (inttoptr (sub (ptrtoint X), (ptrtoint Y)))
-        // The GEP pattern is emitted by the SCEV expander for certain kinds of
-        // pointer arithmetic.
-        if (match(V, m_Neg(m_PtrToInt(m_Value())))) {
-          Operator *Index = cast<Operator>(V);
-          Value *PtrToInt = Builder->CreatePtrToInt(PtrOp, Index->getType());
-          Value *NewSub = Builder->CreateSub(PtrToInt, Index->getOperand(1));
-          return CastInst::Create(Instruction::IntToPtr, NewSub, GEP.getType());
-        }
-        // Canonicalize (gep i8* X, (ptrtoint Y)-(ptrtoint X))
-        // to (bitcast Y)
-        Value *Y;
-        if (match(V, m_Sub(m_PtrToInt(m_Value(Y)),
-                           m_PtrToInt(m_Specific(GEP.getOperand(0)))))) {
-          return CastInst::CreatePointerBitCastOrAddrSpaceCast(Y,
-                                                               GEP.getType());
-        }
-      }
+      Operator *Index = cast<Operator>(GEP.getOperand(1));
+      Value *PtrToInt = Builder->CreatePtrToInt(PtrOp, Index->getType());
+      Value *NewSub = Builder->CreateSub(PtrToInt, Index->getOperand(1));
+      return CastInst::Create(Instruction::IntToPtr, NewSub, GEP.getType());
     }
   }