[llvm] r348602 - Reapply "[DemandedBits][BDCE] Support vectors of integers"

Nikita Popov via llvm-commits llvm-commits at lists.llvm.org
Fri Dec 7 07:38:14 PST 2018


Author: nikic
Date: Fri Dec  7 07:38:13 2018
New Revision: 348602

URL: http://llvm.org/viewvc/llvm-project?rev=348602&view=rev
Log:
Reapply "[DemandedBits][BDCE] Support vectors of integers"

DemandedBits and BDCE currently only support scalar integers. This
patch extends them to also handle vector integer operations. In this
case bits are not tracked for individual vector elements, instead a
bit is demanded if it is demanded for any of the elements. This matches
the behavior of computeKnownBits in ValueTracking and
SimplifyDemandedBits in InstCombine.

Unlike the previous iteration of this patch, getDemandedBits() can now
again be called on arbirary (sized) instructions, even if they don't
have integer or vector of integer type. (For vector types the size of the
returned mask will now be the scalar size in bits though.)

The added LoopVectorize test case shows a case which triggered an
assertion failure with the previous attempt, because getDemandedBits()
was called on a pointer-typed instruction.

Differential Revision: https://reviews.llvm.org/D55297

Added:
    llvm/trunk/test/Analysis/DemandedBits/vectors.ll
    llvm/trunk/test/Transforms/LoopVectorize/demanded-bits-of-pointer-instruction.ll
Modified:
    llvm/trunk/include/llvm/Analysis/DemandedBits.h
    llvm/trunk/lib/Analysis/DemandedBits.cpp
    llvm/trunk/lib/Transforms/Scalar/BDCE.cpp
    llvm/trunk/test/Transforms/BDCE/vectors.ll

Modified: llvm/trunk/include/llvm/Analysis/DemandedBits.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/DemandedBits.h?rev=348602&r1=348601&r2=348602&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/DemandedBits.h (original)
+++ llvm/trunk/include/llvm/Analysis/DemandedBits.h Fri Dec  7 07:38:13 2018
@@ -44,6 +44,14 @@ public:
     F(F), AC(AC), DT(DT) {}
 
   /// Return the bits demanded from instruction I.
+  ///
+  /// For vector instructions individual vector elements are not distinguished:
+  /// A bit is demanded if it is demanded for any of the vector elements. The
+  /// size of the return value corresponds to the type size in bits of the
+  /// scalar type.
+  ///
+  /// Instructions that do not have integer or vector of integer type are
+  /// accepted, but will always produce a mask with all bits set.
   APInt getDemandedBits(Instruction *I);
 
   /// Return true if, during analysis, I could not be reached.

Modified: llvm/trunk/lib/Analysis/DemandedBits.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/DemandedBits.cpp?rev=348602&r1=348601&r2=348602&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/DemandedBits.cpp (original)
+++ llvm/trunk/lib/Analysis/DemandedBits.cpp Fri Dec  7 07:38:13 2018
@@ -39,6 +39,7 @@
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/IR/PatternMatch.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/Use.h"
 #include "llvm/Pass.h"
@@ -50,6 +51,7 @@
 #include <cstdint>
 
 using namespace llvm;
+using namespace llvm::PatternMatch;
 
 #define DEBUG_TYPE "demanded-bits"
 
@@ -143,17 +145,17 @@ void DemandedBits::determineLiveOperandB
         }
         break;
       case Intrinsic::fshl:
-      case Intrinsic::fshr:
+      case Intrinsic::fshr: {
+        const APInt *SA;
         if (OperandNo == 2) {
           // Shift amount is modulo the bitwidth. For powers of two we have
           // SA % BW == SA & (BW - 1).
           if (isPowerOf2_32(BitWidth))
             AB = BitWidth - 1;
-        } else if (auto *SA = dyn_cast<ConstantInt>(II->getOperand(2))) {
-          // TODO: Support vectors.
+        } else if (match(II->getOperand(2), m_APInt(SA))) {
           // Normalize to funnel shift left. APInt shifts of BitWidth are well-
           // defined, so no need to special-case zero shifts here.
-          uint64_t ShiftAmt = SA->getValue().urem(BitWidth);
+          uint64_t ShiftAmt = SA->urem(BitWidth);
           if (II->getIntrinsicID() == Intrinsic::fshr)
             ShiftAmt = BitWidth - ShiftAmt;
 
@@ -164,6 +166,7 @@ void DemandedBits::determineLiveOperandB
         }
         break;
       }
+      }
     break;
   case Instruction::Add:
   case Instruction::Sub:
@@ -174,8 +177,9 @@ void DemandedBits::determineLiveOperandB
     AB = APInt::getLowBitsSet(BitWidth, AOut.getActiveBits());
     break;
   case Instruction::Shl:
-    if (OperandNo == 0)
-      if (auto *ShiftAmtC = dyn_cast<ConstantInt>(UserI->getOperand(1))) {
+    if (OperandNo == 0) {
+      const APInt *ShiftAmtC;
+      if (match(UserI->getOperand(1), m_APInt(ShiftAmtC))) {
         uint64_t ShiftAmt = ShiftAmtC->getLimitedValue(BitWidth - 1);
         AB = AOut.lshr(ShiftAmt);
 
@@ -187,10 +191,12 @@ void DemandedBits::determineLiveOperandB
         else if (S->hasNoUnsignedWrap())
           AB |= APInt::getHighBitsSet(BitWidth, ShiftAmt);
       }
+    }
     break;
   case Instruction::LShr:
-    if (OperandNo == 0)
-      if (auto *ShiftAmtC = dyn_cast<ConstantInt>(UserI->getOperand(1))) {
+    if (OperandNo == 0) {
+      const APInt *ShiftAmtC;
+      if (match(UserI->getOperand(1), m_APInt(ShiftAmtC))) {
         uint64_t ShiftAmt = ShiftAmtC->getLimitedValue(BitWidth - 1);
         AB = AOut.shl(ShiftAmt);
 
@@ -199,10 +205,12 @@ void DemandedBits::determineLiveOperandB
         if (cast<LShrOperator>(UserI)->isExact())
           AB |= APInt::getLowBitsSet(BitWidth, ShiftAmt);
       }
+    }
     break;
   case Instruction::AShr:
-    if (OperandNo == 0)
-      if (auto *ShiftAmtC = dyn_cast<ConstantInt>(UserI->getOperand(1))) {
+    if (OperandNo == 0) {
+      const APInt *ShiftAmtC;
+      if (match(UserI->getOperand(1), m_APInt(ShiftAmtC))) {
         uint64_t ShiftAmt = ShiftAmtC->getLimitedValue(BitWidth - 1);
         AB = AOut.shl(ShiftAmt);
         // Because the high input bit is replicated into the
@@ -217,6 +225,7 @@ void DemandedBits::determineLiveOperandB
         if (cast<AShrOperator>(UserI)->isExact())
           AB |= APInt::getLowBitsSet(BitWidth, ShiftAmt);
       }
+    }
     break;
   case Instruction::And:
     AB = AOut;
@@ -274,6 +283,15 @@ void DemandedBits::determineLiveOperandB
     if (OperandNo != 0)
       AB = AOut;
     break;
+  case Instruction::ExtractElement:
+    if (OperandNo == 0)
+      AB = AOut;
+    break;
+  case Instruction::InsertElement:
+  case Instruction::ShuffleVector:
+    if (OperandNo == 0 || OperandNo == 1)
+      AB = AOut;
+    break;
   }
 }
 
@@ -309,8 +327,9 @@ void DemandedBits::performAnalysis() {
     // bits and add the instruction to the work list. For other instructions
     // add their operands to the work list (for integer values operands, mark
     // all bits as live).
-    if (IntegerType *IT = dyn_cast<IntegerType>(I.getType())) {
-      if (AliveBits.try_emplace(&I, IT->getBitWidth(), 0).second)
+    Type *T = I.getType();
+    if (T->isIntOrIntVectorTy()) {
+      if (AliveBits.try_emplace(&I, T->getScalarSizeInBits(), 0).second)
         Worklist.push_back(&I);
 
       continue;
@@ -319,8 +338,9 @@ void DemandedBits::performAnalysis() {
     // Non-integer-typed instructions...
     for (Use &OI : I.operands()) {
       if (Instruction *J = dyn_cast<Instruction>(OI)) {
-        if (IntegerType *IT = dyn_cast<IntegerType>(J->getType()))
-          AliveBits[J] = APInt::getAllOnesValue(IT->getBitWidth());
+        Type *T = J->getType();
+        if (T->isIntOrIntVectorTy())
+          AliveBits[J] = APInt::getAllOnesValue(T->getScalarSizeInBits());
         Worklist.push_back(J);
       }
     }
@@ -336,13 +356,13 @@ void DemandedBits::performAnalysis() {
 
     LLVM_DEBUG(dbgs() << "DemandedBits: Visiting: " << *UserI);
     APInt AOut;
-    if (UserI->getType()->isIntegerTy()) {
+    if (UserI->getType()->isIntOrIntVectorTy()) {
       AOut = AliveBits[UserI];
       LLVM_DEBUG(dbgs() << " Alive Out: " << AOut);
     }
     LLVM_DEBUG(dbgs() << "\n");
 
-    if (!UserI->getType()->isIntegerTy())
+    if (!UserI->getType()->isIntOrIntVectorTy())
       Visited.insert(UserI);
 
     KnownBits Known, Known2;
@@ -351,10 +371,11 @@ void DemandedBits::performAnalysis() {
     // operand is added to the work-list.
     for (Use &OI : UserI->operands()) {
       if (Instruction *I = dyn_cast<Instruction>(OI)) {
-        if (IntegerType *IT = dyn_cast<IntegerType>(I->getType())) {
-          unsigned BitWidth = IT->getBitWidth();
+        Type *T = I->getType();
+        if (T->isIntOrIntVectorTy()) {
+          unsigned BitWidth = T->getScalarSizeInBits();
           APInt AB = APInt::getAllOnesValue(BitWidth);
-          if (UserI->getType()->isIntegerTy() && !AOut &&
+          if (UserI->getType()->isIntOrIntVectorTy() && !AOut &&
               !isAlwaysLive(UserI)) {
             AB = APInt(BitWidth, 0);
           } else {
@@ -389,11 +410,13 @@ void DemandedBits::performAnalysis() {
 APInt DemandedBits::getDemandedBits(Instruction *I) {
   performAnalysis();
 
-  const DataLayout &DL = I->getModule()->getDataLayout();
   auto Found = AliveBits.find(I);
   if (Found != AliveBits.end())
     return Found->second;
-  return APInt::getAllOnesValue(DL.getTypeSizeInBits(I->getType()));
+
+  const DataLayout &DL = I->getModule()->getDataLayout();
+  return APInt::getAllOnesValue(
+      DL.getTypeSizeInBits(I->getType()->getScalarType()));
 }
 
 bool DemandedBits::isInstructionDead(Instruction *I) {

Modified: llvm/trunk/lib/Transforms/Scalar/BDCE.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/BDCE.cpp?rev=348602&r1=348601&r2=348602&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/BDCE.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/BDCE.cpp Fri Dec  7 07:38:13 2018
@@ -38,7 +38,8 @@ STATISTIC(NumSimplified, "Number of inst
 /// instruction may need to be cleared of assumptions that can no longer be
 /// guaranteed correct.
 static void clearAssumptionsOfUsers(Instruction *I, DemandedBits &DB) {
-  assert(I->getType()->isIntegerTy() && "Trivializing a non-integer value?");
+  assert(I->getType()->isIntOrIntVectorTy() &&
+         "Trivializing a non-integer value?");
 
   // Initialize the worklist with eligible direct users.
   SmallVector<Instruction *, 16> WorkList;
@@ -46,13 +47,13 @@ static void clearAssumptionsOfUsers(Inst
     // If all bits of a user are demanded, then we know that nothing below that
     // in the def-use chain needs to be changed.
     auto *J = dyn_cast<Instruction>(JU);
-    if (J && J->getType()->isSized() &&
+    if (J && J->getType()->isIntOrIntVectorTy() &&
         !DB.getDemandedBits(J).isAllOnesValue())
       WorkList.push_back(J);
 
-    // Note that we need to check for unsized types above before asking for
+    // Note that we need to check for non-int types above before asking for
     // demanded bits. Normally, the only way to reach an instruction with an
-    // unsized type is via an instruction that has side effects (or otherwise
+    // non-int type is via an instruction that has side effects (or otherwise
     // will demand its input bits). However, if we have a readnone function
     // that returns an unsized type (e.g., void), we must avoid asking for the
     // demanded bits of the function call's return value. A void-returning
@@ -78,7 +79,7 @@ static void clearAssumptionsOfUsers(Inst
       // If all bits of a user are demanded, then we know that nothing below
       // that in the def-use chain needs to be changed.
       auto *K = dyn_cast<Instruction>(KU);
-      if (K && !Visited.count(K) && K->getType()->isSized() &&
+      if (K && !Visited.count(K) && K->getType()->isIntOrIntVectorTy() &&
           !DB.getDemandedBits(K).isAllOnesValue())
         WorkList.push_back(K);
     }
@@ -95,7 +96,7 @@ static bool bitTrackingDCE(Function &F,
     if (I.mayHaveSideEffects() && I.use_empty())
       continue;
 
-    if (I.getType()->isIntegerTy() &&
+    if (I.getType()->isIntOrIntVectorTy() &&
         !DB.getDemandedBits(&I).getBoolValue()) {
       // For live instructions that have all dead bits, first make them dead by
       // replacing all uses with something else. Then, if they don't need to

Added: llvm/trunk/test/Analysis/DemandedBits/vectors.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/DemandedBits/vectors.ll?rev=348602&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/DemandedBits/vectors.ll (added)
+++ llvm/trunk/test/Analysis/DemandedBits/vectors.ll Fri Dec  7 07:38:13 2018
@@ -0,0 +1,136 @@
+; RUN: opt -S -demanded-bits -analyze < %s | FileCheck %s
+; RUN: opt -S -disable-output -passes="print<demanded-bits>" < %s 2>&1 | FileCheck %s
+
+; CHECK-DAG: DemandedBits: 0xff00 for   %x = or <2 x i32> %a, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xff00 for   %y = or <2 x i32> %b, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xff00 for   %z = or <2 x i32> %x, %y
+; CHECK-DAG: DemandedBits: 0xff for   %u = lshr <2 x i32> %z, <i32 8, i32 8>
+; CHECK-DAG: DemandedBits: 0xff for   %r = trunc <2 x i32> %u to <2 x i8>
+define <2 x i8> @test_basic(<2 x i32> %a, <2 x i32> %b) {
+  %x = or <2 x i32> %a, zeroinitializer
+  %y = or <2 x i32> %b, zeroinitializer
+  %z = or <2 x i32> %x, %y
+  %u = lshr <2 x i32> %z, <i32 8, i32 8>
+  %r = trunc <2 x i32> %u to <2 x i8>
+  ret <2 x i8> %r
+}
+
+; Vector-specific instructions
+
+; CHECK-DAG: DemandedBits: 0xff for   %x = or <2 x i32> %a, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xf0 for   %z = extractelement <2 x i32> %x, i32 1
+; CHECK-DAG: DemandedBits: 0xf for   %y = extractelement <2 x i32> %x, i32 0
+; CHECK-DAG: DemandedBits: 0xffffffff for   %u = and i32 %y, 15
+; CHECK-DAG: DemandedBits: 0xffffffff for   %v = and i32 %z, 240
+; CHECK-DAG: DemandedBits: 0xffffffff for   %r = or i32 %u, %v
+define i32 @test_extractelement(<2 x i32> %a) {
+  %x = or <2 x i32> %a, zeroinitializer
+  %y = extractelement <2 x i32> %x, i32 0
+  %z = extractelement <2 x i32> %x, i32 1
+  %u = and i32 %y, 15
+  %v = and i32 %z, 240
+  %r = or i32 %u, %v
+  ret i32 %r
+}
+
+; CHECK-DAG: DemandedBits: 0xff for   %x = or i32 %a, 0
+; CHECK-DAG: DemandedBits: 0xff for   %y = or i32 %b, 0
+; CHECK-DAG: DemandedBits: 0xff for   %z = insertelement <2 x i32> undef, i32 %x, i32 0
+; CHECK-DAG: DemandedBits: 0xff for   %u = insertelement <2 x i32> %z, i32 %y, i32 1
+; CHECK-DAG: DemandedBits: 0xffffffff for   %r = and <2 x i32> %u, <i32 255, i32 127>
+define <2 x i32> @test_insertelement(i32 %a, i32 %b) {
+  %x = or i32 %a, 0
+  %y = or i32 %b, 0
+  %z = insertelement <2 x i32> undef, i32 %x, i32 0
+  %u = insertelement <2 x i32> %z, i32 %y, i32 1
+  %r = and <2 x i32> %u, <i32 255, i32 127>
+  ret <2 x i32> %r
+}
+
+; CHECK-DAG: DemandedBits: 0xff for   %x = or <2 x i32> %a, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xff for   %y = or <2 x i32> %b, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xff for   %z = shufflevector <2 x i32> %x, <2 x i32> %y, <3 x i32> <i32 0, i32 3, i32 1>
+; CHECK-DAG: DemandedBits: 0xffffffff for   %r = and <3 x i32> %z, <i32 255, i32 127, i32 0>
+define <3 x i32> @test_shufflevector(<2 x i32> %a, <2 x i32> %b) {
+  %x = or <2 x i32> %a, zeroinitializer
+  %y = or <2 x i32> %b, zeroinitializer
+  %z = shufflevector <2 x i32> %x, <2 x i32> %y, <3 x i32> <i32 0, i32 3, i32 1>
+  %r = and <3 x i32> %z, <i32 255, i32 127, i32 0>
+  ret <3 x i32> %r
+}
+
+; Shifts with splat shift amounts
+
+; CHECK-DAG: DemandedBits: 0xf for   %x = or <2 x i32> %a, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xf0 for   %y = shl <2 x i32> %x, <i32 4, i32 4>
+; CHECK-DAG: DemandedBits: 0xffffffff for   %r = and <2 x i32> %y, <i32 240, i32 240>
+define <2 x i32> @test_shl(<2 x i32> %a) {
+  %x = or <2 x i32> %a, zeroinitializer
+  %y = shl <2 x i32> %x, <i32 4, i32 4>
+  %r = and <2 x i32> %y, <i32 240, i32 240>
+  ret <2 x i32> %r
+}
+
+; CHECK-DAG: DemandedBits: 0xf00 for   %x = or <2 x i32> %a, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xf0 for   %y = ashr <2 x i32> %x, <i32 4, i32 4>
+; CHECK-DAG: DemandedBits: 0xffffffff for   %r = and <2 x i32> %y, <i32 240, i32 240>
+define <2 x i32> @test_ashr(<2 x i32> %a) {
+  %x = or <2 x i32> %a, zeroinitializer
+  %y = ashr <2 x i32> %x, <i32 4, i32 4>
+  %r = and <2 x i32> %y, <i32 240, i32 240>
+  ret <2 x i32> %r
+}
+
+; CHECK-DAG: DemandedBits: 0xf00 for   %x = or <2 x i32> %a, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xf0 for   %y = lshr <2 x i32> %x, <i32 4, i32 4>
+; CHECK-DAG: DemandedBits: 0xffffffff for   %r = and <2 x i32> %y, <i32 240, i32 240>
+define <2 x i32> @test_lshr(<2 x i32> %a) {
+  %x = or <2 x i32> %a, zeroinitializer
+  %y = lshr <2 x i32> %x, <i32 4, i32 4>
+  %r = and <2 x i32> %y, <i32 240, i32 240>
+  ret <2 x i32> %r
+}
+
+declare <2 x i32> @llvm.fshl.i32(<2 x i32>, <2 x i32>, <2 x i32>)
+declare <2 x i32> @llvm.fshr.i32(<2 x i32>, <2 x i32>, <2 x i32>)
+
+; CHECK-DAG: DemandedBits: 0xf for   %x = or <2 x i32> %a, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xf0000000 for   %y = or <2 x i32> %b, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xff for   %z = call <2 x i32> @llvm.fshl.v2i32(<2 x i32> %x, <2 x i32> %y, <2 x i32> <i32 4, i32 4>)
+; CHECK-DAG: DemandedBits: 0xffffffff for   %r = and <2 x i32> %z, <i32 255, i32 255>
+define <2 x i32> @test_fshl(<2 x i32> %a, <2 x i32> %b) {
+  %x = or <2 x i32> %a, zeroinitializer
+  %y = or <2 x i32> %b, zeroinitializer
+  %z = call <2 x i32> @llvm.fshl.i32(<2 x i32> %x, <2 x i32> %y, <2 x i32> <i32 4, i32 4>)
+  %r = and <2 x i32> %z, <i32 255, i32 255>
+  ret <2 x i32> %r
+}
+
+; CHECK-DAG: DemandedBits: 0xf for   %x = or <2 x i32> %a, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xf0000000 for   %y = or <2 x i32> %b, zeroinitializer
+; CHECK-DAG: DemandedBits: 0xff for   %z = call <2 x i32> @llvm.fshr.v2i32(<2 x i32> %x, <2 x i32> %y, <2 x i32> <i32 28, i32 28>)
+; CHECK-DAG: DemandedBits: 0xffffffff for   %r = and <2 x i32> %z, <i32 255, i32 255>
+define <2 x i32> @test_fshr(<2 x i32> %a, <2 x i32> %b) {
+  %x = or <2 x i32> %a, zeroinitializer
+  %y = or <2 x i32> %b, zeroinitializer
+  %z = call <2 x i32> @llvm.fshr.i32(<2 x i32> %x, <2 x i32> %y, <2 x i32> <i32 28, i32 28>)
+  %r = and <2 x i32> %z, <i32 255, i32 255>
+  ret <2 x i32> %r
+}
+
+; FP / Int conversion. These have different input / output types.
+
+; CHECK-DAG: DemandedBits: 0xffffffff for   %x = or <2 x i32> %a, zeroinitializer
+define <2 x float> @test_uitofp(<2 x i32> %a) {
+  %x = or <2 x i32> %a, zeroinitializer
+  %r = uitofp <2 x i32> %x to <2 x float>
+  ret <2 x float> %r
+}
+
+; CHECK-DAG: DemandedBits: 0xffffffff for   %y = fptoui <2 x float> %x to <2 x i32>
+define <2 x i32> @test_fptoui(<2 x float> %a) {
+  %x = fadd <2 x float> %a, <float 1.0, float 1.0>
+  %y = fptoui <2 x float> %x to <2 x i32>
+  %r = and <2 x i32> %y, <i32 255, i32 255>
+  ret <2 x i32> %y
+}

Modified: llvm/trunk/test/Transforms/BDCE/vectors.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/BDCE/vectors.ll?rev=348602&r1=348601&r2=348602&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/BDCE/vectors.ll (original)
+++ llvm/trunk/test/Transforms/BDCE/vectors.ll Fri Dec  7 07:38:13 2018
@@ -7,12 +7,9 @@
 
 define <2 x i32> @test_basic(<2 x i32> %a, <2 x i32> %b) {
 ; CHECK-LABEL: @test_basic(
-; CHECK-NEXT:    [[A2:%.*]] = add <2 x i32> [[A:%.*]], <i32 1, i32 1>
-; CHECK-NEXT:    [[A3:%.*]] = and <2 x i32> [[A2]], <i32 4, i32 4>
 ; CHECK-NEXT:    [[B2:%.*]] = add <2 x i32> [[B:%.*]], <i32 1, i32 1>
 ; CHECK-NEXT:    [[B3:%.*]] = and <2 x i32> [[B2]], <i32 8, i32 8>
-; CHECK-NEXT:    [[C:%.*]] = or <2 x i32> [[A3]], [[B3]]
-; CHECK-NEXT:    [[D:%.*]] = ashr <2 x i32> [[C]], <i32 3, i32 3>
+; CHECK-NEXT:    [[D:%.*]] = ashr <2 x i32> [[B3]], <i32 3, i32 3>
 ; CHECK-NEXT:    ret <2 x i32> [[D]]
 ;
 ; CHECK-IO-LABEL: @test_basic(
@@ -36,12 +33,9 @@ define <2 x i32> @test_basic(<2 x i32> %
 ; Going vector -> scalar
 define i32 @test_extractelement(<2 x i32> %a, <2 x i32> %b) {
 ; CHECK-LABEL: @test_extractelement(
-; CHECK-NEXT:    [[A2:%.*]] = add <2 x i32> [[A:%.*]], <i32 1, i32 1>
-; CHECK-NEXT:    [[A3:%.*]] = and <2 x i32> [[A2]], <i32 4, i32 4>
 ; CHECK-NEXT:    [[B2:%.*]] = add <2 x i32> [[B:%.*]], <i32 1, i32 1>
 ; CHECK-NEXT:    [[B3:%.*]] = and <2 x i32> [[B2]], <i32 8, i32 8>
-; CHECK-NEXT:    [[C:%.*]] = or <2 x i32> [[A3]], [[B3]]
-; CHECK-NEXT:    [[D:%.*]] = extractelement <2 x i32> [[C]], i32 0
+; CHECK-NEXT:    [[D:%.*]] = extractelement <2 x i32> [[B3]], i32 0
 ; CHECK-NEXT:    [[E:%.*]] = ashr i32 [[D]], 3
 ; CHECK-NEXT:    ret i32 [[E]]
 ;
@@ -68,14 +62,10 @@ define i32 @test_extractelement(<2 x i32
 ; Going scalar -> vector
 define <2 x i32> @test_insertelement(i32 %a, i32 %b) {
 ; CHECK-LABEL: @test_insertelement(
-; CHECK-NEXT:    [[X:%.*]] = insertelement <2 x i32> undef, i32 [[A:%.*]], i32 0
-; CHECK-NEXT:    [[X2:%.*]] = insertelement <2 x i32> [[X]], i32 [[B:%.*]], i32 1
-; CHECK-NEXT:    [[X3:%.*]] = and <2 x i32> [[X2]], <i32 4, i32 4>
-; CHECK-NEXT:    [[Y:%.*]] = insertelement <2 x i32> undef, i32 [[B]], i32 0
-; CHECK-NEXT:    [[Y2:%.*]] = insertelement <2 x i32> [[Y]], i32 [[A]], i32 1
+; CHECK-NEXT:    [[Y:%.*]] = insertelement <2 x i32> undef, i32 [[B:%.*]], i32 0
+; CHECK-NEXT:    [[Y2:%.*]] = insertelement <2 x i32> [[Y]], i32 [[A:%.*]], i32 1
 ; CHECK-NEXT:    [[Y3:%.*]] = and <2 x i32> [[Y2]], <i32 8, i32 8>
-; CHECK-NEXT:    [[Z:%.*]] = or <2 x i32> [[X3]], [[Y3]]
-; CHECK-NEXT:    [[U:%.*]] = ashr <2 x i32> [[Z]], <i32 3, i32 3>
+; CHECK-NEXT:    [[U:%.*]] = ashr <2 x i32> [[Y3]], <i32 3, i32 3>
 ; CHECK-NEXT:    ret <2 x i32> [[U]]
 ;
 ; CHECK-IO-LABEL: @test_insertelement(
@@ -132,10 +122,8 @@ define <2 x i32> @test_conversion(<2 x i
 ; Assumption invalidation (adapted from invalidate-assumptions.ll)
 define <2 x i1> @test_assumption_invalidation(<2 x i1> %b, <2 x i8> %x) {
 ; CHECK-LABEL: @test_assumption_invalidation(
-; CHECK-NEXT:    [[SETBIT:%.*]] = or <2 x i8> [[X:%.*]], <i8 64, i8 64>
 ; CHECK-NEXT:    [[LITTLE_NUMBER:%.*]] = zext <2 x i1> [[B:%.*]] to <2 x i8>
-; CHECK-NEXT:    [[BIG_NUMBER:%.*]] = shl <2 x i8> [[SETBIT]], <i8 1, i8 1>
-; CHECK-NEXT:    [[SUB:%.*]] = sub nuw <2 x i8> [[BIG_NUMBER]], [[LITTLE_NUMBER]]
+; CHECK-NEXT:    [[SUB:%.*]] = sub <2 x i8> zeroinitializer, [[LITTLE_NUMBER]]
 ; CHECK-NEXT:    [[TRUNC:%.*]] = trunc <2 x i8> [[SUB]] to <2 x i1>
 ; CHECK-NEXT:    ret <2 x i1> [[TRUNC]]
 ;

Added: llvm/trunk/test/Transforms/LoopVectorize/demanded-bits-of-pointer-instruction.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/demanded-bits-of-pointer-instruction.ll?rev=348602&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/demanded-bits-of-pointer-instruction.ll (added)
+++ llvm/trunk/test/Transforms/LoopVectorize/demanded-bits-of-pointer-instruction.ll Fri Dec  7 07:38:13 2018
@@ -0,0 +1,20 @@
+; RUN: opt < %s -loop-vectorize -S | FileCheck %s
+
+; getDemandedBits() is called on the pointer-typed GEP instruction here.
+; Only make sure we do not crash.
+
+; CHECK: @test
+define void @test(i8* %ptr, i8* %ptr_end) {
+start:
+  br label %loop
+
+loop:
+  %ptr2 = phi i8* [ %ptr3, %loop ], [ %ptr, %start ]
+  %x = sext i8 undef to i64
+  %ptr3 = getelementptr inbounds i8, i8* %ptr2, i64 1
+  %cmp = icmp ult i8* %ptr3, %ptr_end
+  br i1 %cmp, label %loop, label %end
+
+end:
+  ret void
+}




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