[llvm] r216698 - Revert two GEP-related InstCombine commits

[David Majnemer]

Author: majnemer
Date: Thu Aug 28 19:06:43 2014
New Revision: 216698

URL: http://llvm.org/viewvc/llvm-project?rev=216698&view=rev
Log:
Revert two GEP-related InstCombine commits

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

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
    llvm/trunk/test/Transforms/InstCombine/getelementptr.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp?rev=216698&r1=216697&r2=216698&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp Thu Aug 28 19:06:43 2014
@@ -1508,48 +1508,19 @@ Instruction *InstCombiner::visitGetEleme
         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());
     }
   }
 

Modified: llvm/trunk/test/Transforms/InstCombine/getelementptr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/getelementptr.ll?rev=216698&r1=216697&r2=216698&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/getelementptr.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/getelementptr.ll Thu Aug 28 19:06:43 2014
@@ -6,7 +6,6 @@ target datalayout = "e-p:64:64-p1:16:16-
 %pair = type { i32, i32 }
 %struct.B = type { double }
 %struct.A = type { %struct.B, i32, i32 }
-%struct.C = type { [7 x i8] }
 
 
 @Global = constant [10 x i8] c"helloworld"
@@ -814,63 +813,6 @@ define i16 @test41([3 x i32] addrspace(1
 ; CHECK-NEXT: ret i16 8
 }
 
-define i8* @test42(i8* %c1, i8* %c2) {
-  %ptrtoint = ptrtoint i8* %c1 to i64
-  %sub = sub i64 0, %ptrtoint
-  %gep = getelementptr inbounds i8* %c2, i64 %sub
-  ret i8* %gep
-
-; CHECK-LABEL: @test42(
-; CHECK-NEXT:  [[PTRTOINT1:%.*]] = ptrtoint i8* %c1 to i64
-; CHECK-NEXT:  [[PTRTOINT2:%.*]] = ptrtoint i8* %c2 to i64
-; CHECK-NEXT:  [[SUB:%.*]] = sub i64 [[PTRTOINT2]], [[PTRTOINT1]]
-; CHECK-NEXT:  [[INTTOPTR:%.*]] = inttoptr i64 [[SUB]] to i8*
-; CHECK-NEXT:  ret i8* [[INTTOPTR]]
-}
-
-define i16* @test43(i16* %c1, i16* %c2) {
-  %ptrtoint = ptrtoint i16* %c1 to i64
-  %sub = sub i64 0, %ptrtoint
-  %shr = ashr i64 %sub, 1
-  %gep = getelementptr inbounds i16* %c2, i64 %shr
-  ret i16* %gep
-
-; CHECK-LABEL: @test43(
-; CHECK-NEXT:  [[PTRTOINT1:%.*]] = ptrtoint i16* %c1 to i64
-; CHECK-NEXT:  [[PTRTOINT2:%.*]] = ptrtoint i16* %c2 to i64
-; CHECK-NEXT:  [[SUB:%.*]] = sub i64 [[PTRTOINT2]], [[PTRTOINT1]]
-; CHECK-NEXT:  [[INTTOPTR:%.*]] = inttoptr i64 [[SUB]] to i16*
-; CHECK-NEXT:  ret i16* [[INTTOPTR]]
-}
-
-define %struct.C* @test44(%struct.C* %c1, %struct.C* %c2) {
-  %ptrtoint = ptrtoint %struct.C* %c1 to i64
-  %sub = sub i64 0, %ptrtoint
-  %shr = sdiv i64 %sub, 7
-  %gep = getelementptr inbounds %struct.C* %c2, i64 %shr
-  ret %struct.C* %gep
-
-; CHECK-LABEL: @test44(
-; CHECK-NEXT:  [[PTRTOINT1:%.*]] = ptrtoint %struct.C* %c1 to i64
-; CHECK-NEXT:  [[PTRTOINT2:%.*]] = ptrtoint %struct.C* %c2 to i64
-; CHECK-NEXT:  [[SUB:%.*]] = sub i64 [[PTRTOINT2]], [[PTRTOINT1]]
-; CHECK-NEXT:  [[INTTOPTR:%.*]] = inttoptr i64 [[SUB]] to %struct.C*
-; CHECK-NEXT:  ret %struct.C* [[INTTOPTR]]
-}
-
-define %struct.C* @test45(%struct.C* %c1, %struct.C** %c2) {
-  %ptrtoint1 = ptrtoint %struct.C* %c1 to i64
-  %ptrtoint2 = ptrtoint %struct.C** %c2 to i64
-  %sub = sub i64 %ptrtoint2, %ptrtoint1 ; C2 - C1
-  %shr = sdiv i64 %sub, 7
-  %gep = getelementptr inbounds %struct.C* %c1, i64 %shr ; C1 + (C2 - C1)
-  ret %struct.C* %gep
-
-; CHECK-LABEL: @test45(
-; CHECK-NEXT:  [[BITCAST:%.*]] = bitcast %struct.C** %c2 to %struct.C*
-; CHECK-NEXT:  ret %struct.C* [[BITCAST]]
-}
-
 define i32 addrspace(1)* @ascast_0_gep(i32* %p) nounwind {
 ; CHECK-LABEL: @ascast_0_gep(
 ; CHECK-NOT: getelementptr