Addressed comments

Author: npanchen

llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp

@@ -2631,14 +2631,16 @@ Instruction *InstCombinerImpl::visitSub(BinaryOperator &I) {
                                                /* IsNUW */ false))
       return replaceInstUsesWith(I, Res);
 
-  if (match(Op0, m_ZExt(m_PtrToInt(m_Value(LHSOp)))) &&
+  if (match(Op0, m_ZExt(m_PtrToIntSameSize(DL, m_Value(LHSOp)))) &&
       match(Op1, m_ZExtOrSelf(m_PtrToInt(m_Value(RHSOp))))) {
     if (auto *GEP = dyn_cast<GEPOperator>(LHSOp)) {
       if (GEP->getPointerOperand() == RHSOp) {
         if (GEP->hasNoUnsignedWrap() || GEP->hasNoUnsignedSignedWrap()) {
           Value *Offset = EmitGEPOffset(GEP);
           Value *Res = GEP->hasNoUnsignedWrap()
-                           ? Builder.CreateZExt(Offset, I.getType())
+                           ? Builder.CreateZExt(
+                                 Offset, I.getType(), "",
+                                 /*IsNonNeg=*/GEP->hasNoUnsignedSignedWrap())
                            : Builder.CreateSExt(Offset, I.getType());
           return replaceInstUsesWith(I, Res);
         }

llvm/test/Transforms/InstCombine/sub-gep.ll

@@ -340,6 +340,18 @@ define i64 @zext_ptrtoint_sub_ptrtoint_as2_nuw(i32 %offset) {
   ret i64 %D
 }
 
+define i64 @zext_ptrtoint_sub_ptrtoint_as2_nusw_nuw(i32 %offset) {
+; CHECK-LABEL: @zext_ptrtoint_sub_ptrtoint_as2_nusw_nuw(
+; CHECK-NEXT:  %A.idx = shl nuw nsw i32 %offset, 1
+; CHECK-NEXT:  %D = zext nneg i32 %A.idx to i64
+; CHECK-NEXT:  ret i64 %D
+  %A = getelementptr nusw nuw bfloat, ptr addrspace(2) @Arr_as2, i32 %offset
+  %B = ptrtoint ptr addrspace(2) %A to i32
+  %C = zext i32 %B to i64
+  %D = sub i64 %C, ptrtoint (ptr addrspace(2) @Arr_as2 to i64)
+  ret i64 %D
+}
+
 define i64 @zext_ptrtoint_sub_zext_ptrtoint_as2(i32 %offset) {
 ; CHECK-LABEL: @zext_ptrtoint_sub_zext_ptrtoint_as2(
 ; CHECK-NEXT:  %A.idx = shl nsw i32 %offset, 1
@@ -366,6 +378,21 @@ define i64 @zext_ptrtoint_sub_zext_ptrtoint_as2_nuw(i32 %offset) {
   ret i64 %E
 }
 
+define i64 @negative_zext_ptrtoint_sub_ptrtoint_as2_nuw(i32 %offset) {
+  ; CHECK-LABEL: @negative_zext_ptrtoint_sub_ptrtoint_as2_nuw(
+  ; CHECK-NEXT:  %A = getelementptr nuw bfloat, ptr addrspace(2) @Arr_as2, i32 %offset
+  ; CHECK-NEXT:  %1 = ptrtoint ptr addrspace(2) %A to i32
+  ; CHECK-NEXT:  %B.mask = and i32 %1, 65534
+  ; CHECK-NEXT:  %C = zext nneg i32 %B.mask to i64
+  ; CHECK-NEXT:  %D = sub nsw i64 %C, ptrtoint (ptr addrspace(2) @Arr_as2 to i64)
+  ; CHECK-NEXT:  ret i64 %D
+  %A = getelementptr nuw bfloat, ptr addrspace(2) @Arr_as2, i32 %offset
+  %B = ptrtoint ptr addrspace(2) %A to i16
+  %C = zext i16 %B to i64
+  %D = sub i64 %C, ptrtoint (ptr addrspace(2) @Arr_as2 to i64)
+  ret i64 %D
+}
+
 define i64 @ptrtoint_sub_zext_ptrtoint_as2(i32 %offset) {
 ; CHECK-LABEL: @ptrtoint_sub_zext_ptrtoint_as2(
 ; CHECK-NEXT:  %A = getelementptr inbounds bfloat, ptr addrspace(2) @Arr_as2, i32 %offset