diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2206,12 +2206,13 @@
     Value *UnderlyingPtrOp =
             PtrOp->stripAndAccumulateInBoundsConstantOffsets(DL,
                                                              BasePtrOffset);
-    if (auto *AI = dyn_cast<AllocaInst>(UnderlyingPtrOp)) {
+    bool CanBeNull, CanBeFreed;
+    uint64_t DerefBytes = UnderlyingPtrOp->getPointerDereferenceableBytes(
+        DL, CanBeNull, CanBeFreed);
+    if (!CanBeNull && !CanBeFreed && DerefBytes != 0) {
       if (GEP.accumulateConstantOffset(DL, BasePtrOffset) &&
           BasePtrOffset.isNonNegative()) {
-        APInt AllocSize(
-            IdxWidth,
-            DL.getTypeAllocSize(AI->getAllocatedType()).getKnownMinValue());
+        APInt AllocSize(IdxWidth, DerefBytes);
         if (BasePtrOffset.ule(AllocSize)) {
           return GetElementPtrInst::CreateInBounds(
               GEP.getSourceElementType(), PtrOp, Indices, GEP.getName());
diff --git a/llvm/test/Transforms/InstCombine/compare-unescaped.ll b/llvm/test/Transforms/InstCombine/compare-unescaped.ll
--- a/llvm/test/Transforms/InstCombine/compare-unescaped.ll
+++ b/llvm/test/Transforms/InstCombine/compare-unescaped.ll
@@ -382,8 +382,8 @@
 ; CHECK-LABEL: @two_nonnull_mallocs_hidden(
 ; CHECK-NEXT:    [[M:%.*]] = call nonnull dereferenceable(4) ptr @malloc(i64 4)
 ; CHECK-NEXT:    [[N:%.*]] = call nonnull dereferenceable(4) ptr @malloc(i64 4)
-; CHECK-NEXT:    [[GEP1:%.*]] = getelementptr i8, ptr [[M]], i64 1
-; CHECK-NEXT:    [[GEP2:%.*]] = getelementptr i8, ptr [[N]], i64 2
+; CHECK-NEXT:    [[GEP1:%.*]] = getelementptr inbounds i8, ptr [[M]], i64 1
+; CHECK-NEXT:    [[GEP2:%.*]] = getelementptr inbounds i8, ptr [[N]], i64 2
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp eq ptr [[GEP1]], [[GEP2]]
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
diff --git a/llvm/test/Transforms/InstCombine/inbounds-gep.ll b/llvm/test/Transforms/InstCombine/inbounds-gep.ll
--- a/llvm/test/Transforms/InstCombine/inbounds-gep.ll
+++ b/llvm/test/Transforms/InstCombine/inbounds-gep.ll
@@ -19,8 +19,8 @@
 define void @call2() {
 ; CHECK-LABEL: define void @call2() {
 ; CHECK-NEXT:    [[A:%.*]] = call dereferenceable(8) ptr @g()
-; CHECK-NEXT:    [[B:%.*]] = getelementptr i8, ptr [[A]], i64 4
-; CHECK-NEXT:    call void @use(ptr [[B]])
+; CHECK-NEXT:    [[B:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 4
+; CHECK-NEXT:    call void @use(ptr nonnull [[B]])
 ; CHECK-NEXT:    ret void
 ;
   %a = call dereferenceable(8) ptr @g()
@@ -70,8 +70,8 @@
 define void @arg2(ptr dereferenceable(8) %a) {
 ; CHECK-LABEL: define void @arg2
 ; CHECK-SAME: (ptr dereferenceable(8) [[A:%.*]]) {
-; CHECK-NEXT:    [[B:%.*]] = getelementptr i8, ptr [[A]], i64 4
-; CHECK-NEXT:    call void @use(ptr [[B]])
+; CHECK-NEXT:    [[B:%.*]] = getelementptr inbounds i8, ptr [[A]], i64 4
+; CHECK-NEXT:    call void @use(ptr nonnull [[B]])
 ; CHECK-NEXT:    ret void
 ;
   %b = getelementptr i8, ptr %a, i64 4
diff --git a/llvm/test/Transforms/PhaseOrdering/X86/vec-load-combine.ll b/llvm/test/Transforms/PhaseOrdering/X86/vec-load-combine.ll
--- a/llvm/test/Transforms/PhaseOrdering/X86/vec-load-combine.ll
+++ b/llvm/test/Transforms/PhaseOrdering/X86/vec-load-combine.ll
@@ -48,7 +48,7 @@
 ; SSE-LABEL: @ConvertVectors_ByVal(
 ; SSE-NEXT:  entry:
 ; SSE-NEXT:    [[TMP0:%.*]] = load <4 x float>, ptr [[V:%.*]], align 16
-; SSE-NEXT:    [[TMP1:%.*]] = getelementptr i8, ptr [[V]], i64 8
+; SSE-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[V]], i64 8
 ; SSE-NEXT:    [[V_VAL421:%.*]] = load i64, ptr [[TMP1]], align 8
 ; SSE-NEXT:    [[TMP2:%.*]] = trunc i64 [[V_VAL421]] to i32
 ; SSE-NEXT:    [[TMP3:%.*]] = bitcast i32 [[TMP2]] to float
@@ -59,7 +59,7 @@
 ; AVX-LABEL: @ConvertVectors_ByVal(
 ; AVX-NEXT:  entry:
 ; AVX-NEXT:    [[TMP0:%.*]] = load <4 x float>, ptr [[V:%.*]], align 16
-; AVX-NEXT:    [[TMP1:%.*]] = getelementptr i8, ptr [[V]], i64 8
+; AVX-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[V]], i64 8
 ; AVX-NEXT:    [[V_VAL421:%.*]] = load i64, ptr [[TMP1]], align 8
 ; AVX-NEXT:    [[TMP2:%.*]] = trunc i64 [[V_VAL421]] to i32
 ; AVX-NEXT:    [[TMP3:%.*]] = bitcast i32 [[TMP2]] to float
diff --git a/llvm/test/Transforms/PhaseOrdering/bitcast-store-branch.ll b/llvm/test/Transforms/PhaseOrdering/bitcast-store-branch.ll
--- a/llvm/test/Transforms/PhaseOrdering/bitcast-store-branch.ll
+++ b/llvm/test/Transforms/PhaseOrdering/bitcast-store-branch.ll
@@ -14,7 +14,7 @@
 ; CHECK-LABEL: define nonnull ptr @parent
 ; CHECK-SAME: (ptr readonly returned align 8 dereferenceable(72) [[F:%.*]], half [[VAL1:%.*]], i16 [[VAL2:%.*]], i32 [[VAL3:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] align 2 {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr i8, ptr [[F]], i64 64
+; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[F]], i64 64
 ; CHECK-NEXT:    [[F_VAL:%.*]] = load ptr, ptr [[TMP0]], align 8
 ; CHECK-NEXT:    [[CMP_NOT_NOT_I:%.*]] = icmp eq i32 [[VAL3]], 0
 ; CHECK-NEXT:    [[TMP1:%.*]] = bitcast half [[VAL1]] to i16
diff --git a/llvm/test/Transforms/PhaseOrdering/dce-after-argument-promotion-loads.ll b/llvm/test/Transforms/PhaseOrdering/dce-after-argument-promotion-loads.ll
--- a/llvm/test/Transforms/PhaseOrdering/dce-after-argument-promotion-loads.ll
+++ b/llvm/test/Transforms/PhaseOrdering/dce-after-argument-promotion-loads.ll
@@ -16,7 +16,7 @@
 ; CHECK-LABEL: define nonnull ptr @parent
 ; CHECK-SAME: (ptr readonly returned align 8 dereferenceable(72) [[F:%.*]], i16 [[VAL1:%.*]], i16 [[VAL2:%.*]], i32 [[VAL3:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] align 2 {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr i8, ptr [[F]], i64 64
+; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[F]], i64 64
 ; CHECK-NEXT:    [[F_VAL:%.*]] = load ptr, ptr [[TMP0]], align 8
 ; CHECK-NEXT:    [[CMP_NOT_NOT_I:%.*]] = icmp eq i32 [[VAL3]], 0
 ; CHECK-NEXT:    [[SPEC_SELECT_I:%.*]] = select i1 [[CMP_NOT_NOT_I]], i16 [[VAL1]], i16 [[VAL2]]