[InstCombine] Move gep of phi fold into separate function

This makes sure that an early return during this fold doesn't end
up skipping later gep folds.

Author: nikic

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -2756,6 +2756,111 @@ static bool shouldCanonicalizeGEPToPtrAdd(GetElementPtrInst &GEP) {
          });
 }
 
+static Instruction *foldGEPOfPhi(GetElementPtrInst &GEP, PHINode *PN,
+                                 IRBuilderBase &Builder) {
+  auto *Op1 = dyn_cast<GetElementPtrInst>(PN->getOperand(0));
+  if (!Op1)
+    return nullptr;
+
+  // Don't fold a GEP into itself through a PHI node. This can only happen
+  // through the back-edge of a loop. Folding a GEP into itself means that
+  // the value of the previous iteration needs to be stored in the meantime,
+  // thus requiring an additional register variable to be live, but not
+  // actually achieving anything (the GEP still needs to be executed once per
+  // loop iteration).
+  if (Op1 == &GEP)
+    return nullptr;
+
+  int DI = -1;
+
+  for (auto I = PN->op_begin()+1, E = PN->op_end(); I !=E; ++I) {
+    auto *Op2 = dyn_cast<GetElementPtrInst>(*I);
+    if (!Op2 || Op1->getNumOperands() != Op2->getNumOperands() ||
+        Op1->getSourceElementType() != Op2->getSourceElementType())
+      return nullptr;
+
+    // As for Op1 above, don't try to fold a GEP into itself.
+    if (Op2 == &GEP)
+      return nullptr;
+
+    // Keep track of the type as we walk the GEP.
+    Type *CurTy = nullptr;
+
+    for (unsigned J = 0, F = Op1->getNumOperands(); J != F; ++J) {
+      if (Op1->getOperand(J)->getType() != Op2->getOperand(J)->getType())
+        return nullptr;
+
+      if (Op1->getOperand(J) != Op2->getOperand(J)) {
+        if (DI == -1) {
+          // We have not seen any differences yet in the GEPs feeding the
+          // PHI yet, so we record this one if it is allowed to be a
+          // variable.
+
+          // The first two arguments can vary for any GEP, the rest have to be
+          // static for struct slots
+          if (J > 1) {
+            assert(CurTy && "No current type?");
+            if (CurTy->isStructTy())
+              return nullptr;
+          }
+
+          DI = J;
+        } else {
+          // The GEP is different by more than one input. While this could be
+          // extended to support GEPs that vary by more than one variable it
+          // doesn't make sense since it greatly increases the complexity and
+          // would result in an R+R+R addressing mode which no backend
+          // directly supports and would need to be broken into several
+          // simpler instructions anyway.
+          return nullptr;
+        }
+      }
+
+      // Sink down a layer of the type for the next iteration.
+      if (J > 0) {
+        if (J == 1) {
+          CurTy = Op1->getSourceElementType();
+        } else {
+          CurTy =
+              GetElementPtrInst::getTypeAtIndex(CurTy, Op1->getOperand(J));
+        }
+      }
+    }
+  }
+
+  // If not all GEPs are identical we'll have to create a new PHI node.
+  // Check that the old PHI node has only one use so that it will get
+  // removed.
+  if (DI != -1 && !PN->hasOneUse())
+    return nullptr;
+
+  auto *NewGEP = cast<GetElementPtrInst>(Op1->clone());
+  if (DI == -1) {
+    // All the GEPs feeding the PHI are identical. Clone one down into our
+    // BB so that it can be merged with the current GEP.
+  } else {
+    // All the GEPs feeding the PHI differ at a single offset. Clone a GEP
+    // into the current block so it can be merged, and create a new PHI to
+    // set that index.
+    PHINode *NewPN;
+    {
+      IRBuilderBase::InsertPointGuard Guard(Builder);
+      Builder.SetInsertPoint(PN);
+      NewPN = Builder.CreatePHI(Op1->getOperand(DI)->getType(),
+                                PN->getNumOperands());
+    }
+
+    for (auto &I : PN->operands())
+      NewPN->addIncoming(cast<GEPOperator>(I)->getOperand(DI),
+                         PN->getIncomingBlock(I));
+
+    NewGEP->setOperand(DI, NewPN);
+  }
+
+  NewGEP->insertBefore(*GEP.getParent(), GEP.getParent()->getFirstInsertionPt());
+  return NewGEP;
+}
+
 Instruction *InstCombinerImpl::visitGetElementPtrInst(GetElementPtrInst &GEP) {
   Value *PtrOp = GEP.getOperand(0);
   SmallVector<Value *, 8> Indices(GEP.indices());
@@ -2846,107 +2951,8 @@ Instruction *InstCombinerImpl::visitGetElementPtrInst(GetElementPtrInst &GEP) {
 
   // Check to see if the inputs to the PHI node are getelementptr instructions.
   if (auto *PN = dyn_cast<PHINode>(PtrOp)) {
-    auto *Op1 = dyn_cast<GetElementPtrInst>(PN->getOperand(0));
-    if (!Op1)
-      return nullptr;
-
-    // Don't fold a GEP into itself through a PHI node. This can only happen
-    // through the back-edge of a loop. Folding a GEP into itself means that
-    // the value of the previous iteration needs to be stored in the meantime,
-    // thus requiring an additional register variable to be live, but not
-    // actually achieving anything (the GEP still needs to be executed once per
-    // loop iteration).
-    if (Op1 == &GEP)
-      return nullptr;
-
-    int DI = -1;
-
-    for (auto I = PN->op_begin()+1, E = PN->op_end(); I !=E; ++I) {
-      auto *Op2 = dyn_cast<GetElementPtrInst>(*I);
-      if (!Op2 || Op1->getNumOperands() != Op2->getNumOperands() ||
-          Op1->getSourceElementType() != Op2->getSourceElementType())
-        return nullptr;
-
-      // As for Op1 above, don't try to fold a GEP into itself.
-      if (Op2 == &GEP)
-        return nullptr;
-
-      // Keep track of the type as we walk the GEP.
-      Type *CurTy = nullptr;
-
-      for (unsigned J = 0, F = Op1->getNumOperands(); J != F; ++J) {
-        if (Op1->getOperand(J)->getType() != Op2->getOperand(J)->getType())
-          return nullptr;
-
-        if (Op1->getOperand(J) != Op2->getOperand(J)) {
-          if (DI == -1) {
-            // We have not seen any differences yet in the GEPs feeding the
-            // PHI yet, so we record this one if it is allowed to be a
-            // variable.
-
-            // The first two arguments can vary for any GEP, the rest have to be
-            // static for struct slots
-            if (J > 1) {
-              assert(CurTy && "No current type?");
-              if (CurTy->isStructTy())
-                return nullptr;
-            }
-
-            DI = J;
-          } else {
-            // The GEP is different by more than one input. While this could be
-            // extended to support GEPs that vary by more than one variable it
-            // doesn't make sense since it greatly increases the complexity and
-            // would result in an R+R+R addressing mode which no backend
-            // directly supports and would need to be broken into several
-            // simpler instructions anyway.
-            return nullptr;
-          }
-        }
-
-        // Sink down a layer of the type for the next iteration.
-        if (J > 0) {
-          if (J == 1) {
-            CurTy = Op1->getSourceElementType();
-          } else {
-            CurTy =
-                GetElementPtrInst::getTypeAtIndex(CurTy, Op1->getOperand(J));
-          }
-        }
-      }
-    }
-
-    // If not all GEPs are identical we'll have to create a new PHI node.
-    // Check that the old PHI node has only one use so that it will get
-    // removed.
-    if (DI != -1 && !PN->hasOneUse())
-      return nullptr;
-
-    auto *NewGEP = cast<GetElementPtrInst>(Op1->clone());
-    if (DI == -1) {
-      // All the GEPs feeding the PHI are identical. Clone one down into our
-      // BB so that it can be merged with the current GEP.
-    } else {
-      // All the GEPs feeding the PHI differ at a single offset. Clone a GEP
-      // into the current block so it can be merged, and create a new PHI to
-      // set that index.
-      PHINode *NewPN;
-      {
-        IRBuilderBase::InsertPointGuard Guard(Builder);
-        Builder.SetInsertPoint(PN);
-        NewPN = Builder.CreatePHI(Op1->getOperand(DI)->getType(),
-                                  PN->getNumOperands());
-      }
-
-      for (auto &I : PN->operands())
-        NewPN->addIncoming(cast<GEPOperator>(I)->getOperand(DI),
-                           PN->getIncomingBlock(I));
-
-      NewGEP->setOperand(DI, NewPN);
-    }
-
-    NewGEP->insertBefore(*GEP.getParent(), GEP.getParent()->getFirstInsertionPt());
-    return replaceOperand(GEP, 0, NewGEP);
+    if (Value *NewPtrOp = foldGEPOfPhi(GEP, PN, Builder))
+      return replaceOperand(GEP, 0, NewPtrOp);
   }
 
   if (auto *Src = dyn_cast<GEPOperator>(PtrOp))

llvm/test/Analysis/ValueTracking/phi-known-bits.ll

@@ -436,7 +436,7 @@ define i1 @recursiveGEP_withPtrSub1(ptr %val1) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[VAL1:%.*]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -467,7 +467,7 @@ define i1 @recursiveGEP_withPtrSub1_PhiOperandsCommuted(ptr %val1) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[VAL1:%.*]], [[ENTRY:%.*]] ], [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -498,7 +498,7 @@ define i1 @recursiveGEP_withPtrSub1_SubOperandsCommuted(ptr %val1) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[VAL1:%.*]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -561,7 +561,7 @@ define i1 @recursiveGEP_withPtrSub3(ptr %val1) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[TEST_VAL1]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -594,7 +594,7 @@ define i1 @recursiveGEP_withPtrSub1_notKnownNonEqual1(ptr %val1, i64 %val2) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[VAL1:%.*]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -629,7 +629,7 @@ define i1 @recursiveGEP_withPtrSub1_notKnownNonEqual2(ptr %val1) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[TEST_VAL1]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -697,7 +697,7 @@ define i1 @recursiveGEP_withPtrSub_maybeZero(ptr %val1) {
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[VAL1:%.*]], [[ENTRY:%.*]] ]
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[A_PN_I]], align 2
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
 ; CHECK:       while.end.i:
@@ -867,7 +867,7 @@ define i1 @recursiveGEP_withPtrSub_noninboundSameDefStartAndB(ptr %val1) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[TEST]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -903,7 +903,7 @@ define i1 @recursiveGEP_withPtrSub_noninboundSameStartAndB(ptr %val1) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[TEST]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -1004,7 +1004,7 @@ define i1 @recursiveGEP_orcmp(ptr %val1, i64 %val2) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[VAL1:%.*]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -1036,7 +1036,7 @@ define i1 @recursiveGEP_orcmp_orOperandsCommuted(ptr %val1, i64 %val2) {
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[VAL1:%.*]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]
@@ -1069,7 +1069,7 @@ define i1 @recursiveGEP_orcmpMultiUse(ptr %val1, i64 %val2, ptr %dv1, ptr %dv2)
 ; CHECK-NEXT:    br label [[WHILE_COND_I:%.*]]
 ; CHECK:       while.cond.i:
 ; CHECK-NEXT:    [[A_PN_I:%.*]] = phi ptr [ [[TEST_0_I:%.*]], [[WHILE_COND_I]] ], [ [[VAL1:%.*]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds i8, ptr [[A_PN_I]], i64 1
+; CHECK-NEXT:    [[TEST_0_I]] = getelementptr inbounds nuw i8, ptr [[A_PN_I]], i64 1
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[TEST_0_I]], align 2
 ; CHECK-NEXT:    [[CMP3_NOT_I:%.*]] = icmp eq i8 [[TMP0]], 0
 ; CHECK-NEXT:    br i1 [[CMP3_NOT_I]], label [[WHILE_END_I:%.*]], label [[WHILE_COND_I]]

llvm/test/Transforms/InstCombine/gepphigep.ll

@@ -144,15 +144,15 @@ define ptr @test4(i32 %value, ptr %buffer) {
 ; CHECK:       loop.body:
 ; CHECK-NEXT:    [[BUFFER_PN:%.*]] = phi ptr [ [[BUFFER:%.*]], [[LOOP_HEADER]] ], [ [[LOOPPTR:%.*]], [[LOOP_BODY]] ]
 ; CHECK-NEXT:    [[NEWVAL:%.*]] = phi i32 [ [[VALUE]], [[LOOP_HEADER]] ], [ [[SHR:%.*]], [[LOOP_BODY]] ]
-; CHECK-NEXT:    [[LOOPPTR]] = getelementptr inbounds i8, ptr [[BUFFER_PN]], i64 1
+; CHECK-NEXT:    [[LOOPPTR]] = getelementptr inbounds nuw i8, ptr [[BUFFER_PN]], i64 1
 ; CHECK-NEXT:    [[SHR]] = lshr i32 [[NEWVAL]], 7
 ; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt i32 [[NEWVAL]], 16383
 ; CHECK-NEXT:    br i1 [[CMP2]], label [[LOOP_BODY]], label [[LOOP_EXIT:%.*]]
 ; CHECK:       loop.exit:
 ; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    [[TMP0:%.*]] = phi ptr [ [[LOOPPTR]], [[LOOP_EXIT]] ], [ [[BUFFER]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[INCPTR3:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i64 2
+; CHECK-NEXT:    [[INCPTR3:%.*]] = getelementptr inbounds nuw i8, ptr [[TMP0]], i64 2
 ; CHECK-NEXT:    ret ptr [[INCPTR3]]
 ;
 entry:
@@ -203,10 +203,10 @@ define void @test5(ptr %idx, ptr %in) #0 {
 ; CHECK-NEXT:    [[LNOT:%.*]] = icmp eq i8 [[AND]], 0
 ; CHECK-NEXT:    br i1 [[LNOT]], label [[WHILE_BODY]], label [[WHILE_COND_33:%.*]]
 ; CHECK:       while.body:
-; CHECK-NEXT:    [[INCDEC_PTR32]] = getelementptr inbounds i8, ptr [[PTR]], i64 1
+; CHECK-NEXT:    [[INCDEC_PTR32]] = getelementptr inbounds nuw i8, ptr [[PTR]], i64 1
 ; CHECK-NEXT:    br label [[WHILE_COND]]
 ; CHECK:       while.cond.33:
-; CHECK-NEXT:    [[INCDEC_PTR34:%.*]] = getelementptr inbounds i8, ptr [[PTR]], i64 1
+; CHECK-NEXT:    [[INCDEC_PTR34:%.*]] = getelementptr inbounds nuw i8, ptr [[PTR]], i64 1
 ; CHECK-NEXT:    br label [[WHILE_COND_57:%.*]]
 ; CHECK:       while.cond.57:
 ; CHECK-NEXT:    [[TMP3:%.*]] = load i8, ptr [[INCDEC_PTR34]], align 1

llvm/test/Transforms/InstCombine/indexed-gep-compares.ll

@@ -136,7 +136,7 @@ define ptr @test3_no_inbounds1(ptr %A, i32 %Offset) {
 ; CHECK:       bb:
 ; CHECK-NEXT:    [[RHS:%.*]] = phi ptr [ [[RHS_NEXT:%.*]], [[BB]] ], [ [[TMP]], [[ENTRY:%.*]] ]
 ; CHECK-NEXT:    [[LHS:%.*]] = getelementptr inbounds nuw i8, ptr [[A]], i32 400
-; CHECK-NEXT:    [[RHS_NEXT]] = getelementptr inbounds i8, ptr [[RHS]], i32 4
+; CHECK-NEXT:    [[RHS_NEXT]] = getelementptr inbounds nuw i8, ptr [[RHS]], i32 4
 ; CHECK-NEXT:    [[COND:%.*]] = icmp ult ptr [[LHS]], [[RHS]]
 ; CHECK-NEXT:    br i1 [[COND]], label [[BB2:%.*]], label [[BB]]
 ; CHECK:       bb2:
@@ -194,7 +194,7 @@ define ptr @test3_no_inbounds3(ptr %A, i32 %Offset) {
 ; CHECK:       bb:
 ; CHECK-NEXT:    [[RHS:%.*]] = phi ptr [ [[RHS_NEXT:%.*]], [[BB]] ], [ [[TMP]], [[ENTRY:%.*]] ]
 ; CHECK-NEXT:    [[LHS:%.*]] = getelementptr i8, ptr [[A]], i32 400
-; CHECK-NEXT:    [[RHS_NEXT]] = getelementptr inbounds i8, ptr [[RHS]], i32 4
+; CHECK-NEXT:    [[RHS_NEXT]] = getelementptr inbounds nuw i8, ptr [[RHS]], i32 4
 ; CHECK-NEXT:    [[COND:%.*]] = icmp ult ptr [[LHS]], [[RHS]]
 ; CHECK-NEXT:    br i1 [[COND]], label [[BB2:%.*]], label [[BB]]
 ; CHECK:       bb2: