[InstSimplify] Move fold into InstSimplify

Author: dtcxzyw

llvm/lib/Analysis/InstructionSimplify.cpp

@@ -5042,6 +5042,14 @@ static Value *simplifyGEPInst(Type *SrcTy, Value *Ptr,
   if (Q.isUndefValue(Ptr))
     return UndefValue::get(GEPTy);
 
+  // getelementptr inbounds null, idx -> null
+  if (NW.isInBounds() && Q.IIQ.UseInstrInfo && Q.CxtI) {
+    if (auto *BaseC = dyn_cast<Constant>(Ptr))
+      if (BaseC->isNullValue() &&
+          !NullPointerIsDefined(Q.CxtI->getFunction(), AS))
+        return Constant::getNullValue(GEPTy);
+  }
+
   bool IsScalableVec =
       SrcTy->isScalableTy() || any_of(Indices, [](const Value *V) {
         return isa<ScalableVectorType>(V->getType());

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -2911,13 +2911,6 @@ Instruction *InstCombinerImpl::visitGetElementPtrInst(GetElementPtrInst &GEP) {
                           SQ.getWithInstruction(&GEP)))
     return replaceInstUsesWith(GEP, V);
 
-  // getelementptr inbounds null, idx -> null
-  if (auto *BaseC = dyn_cast<Constant>(PtrOp))
-    if (GEP.isInBounds() && BaseC->isNullValue() &&
-        !NullPointerIsDefined(GEP.getFunction(),
-                              GEPType->getPointerAddressSpace()))
-      return replaceInstUsesWith(GEP, Constant::getNullValue(GEPType));
-
   // For vector geps, use the generic demanded vector support.
   // Skip if GEP return type is scalable. The number of elements is unknown at
   // compile-time.

llvm/test/Analysis/MemoryDependenceAnalysis/InvariantLoad.ll

@@ -135,7 +135,7 @@ alive:
 
 ; This is reduced test case catching regression in the first version of the
 ; fix for invariant loads (https://reviews.llvm.org/D64405).
-define void @test4() {
+define void @test4() null_pointer_is_valid {
 ; CHECK-LABEL: @test4(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[TMP0:%.*]] = load float, ptr inttoptr (i64 8 to ptr), align 4

llvm/test/Analysis/ValueTracking/gep-negative-issue.ll

@@ -5,7 +5,7 @@ target triple = "x86_64-unknown-linux-gnu"
 %ArrayImpl = type { i64, ptr addrspace(100), [1 x i64], [1 x i64], [1 x i64], i64, i64, ptr addrspace(100), ptr addrspace(100), i8, i64 }
 %_array = type { i64, ptr addrspace(100), i8 }
 
-define void @test(i64 %n_chpl) {
+define void @test(i64 %n_chpl) null_pointer_is_valid {
 entry:
   ; First section is some code
   %0 = getelementptr inbounds %_array, ptr null, i32 0, i32 1

llvm/test/CodeGen/AMDGPU/chain-hi-to-lo.ll

@@ -402,7 +402,7 @@ bb:
   ret <2 x half> %result
 }
 
-define <2 x half> @chain_hi_to_lo_flat() {
+define <2 x half> @chain_hi_to_lo_flat() null_pointer_is_valid {
 ; GCN-LABEL: chain_hi_to_lo_flat:
 ; GCN:       ; %bb.0: ; %bb
 ; GCN-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)

llvm/test/CodeGen/AMDGPU/memcpy-crash-issue63986.ll

@@ -3,7 +3,7 @@
 
 %"struct.__llvm_libc::rpc::Buffer" = type { [8 x i64] }
 
-define void @issue63986(i64 %0, i64 %idxprom) {
+define void @issue63986(i64 %0, i64 %idxprom) null_pointer_is_valid {
 ; CHECK-LABEL: issue63986:
 ; CHECK:       ; %bb.0: ; %entry
 ; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)

llvm/test/Transforms/GVN/constexpr-vector-constainsundef-crash-inseltpoison.ll

@@ -5,7 +5,7 @@
 ; https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=24278
 
 ; Make sure we do not crash when dealing with a vector constant expression.
-define <4 x ptr> @test(ptr %ptr) {
+define <4 x ptr> @test(ptr %ptr) null_pointer_is_valid {
 ; CHECK-LABEL: @test(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[L3:%.*]] = load i64, ptr [[PTR:%.*]], align 4

llvm/test/Transforms/GVN/constexpr-vector-constainsundef-crash.ll

@@ -5,7 +5,7 @@
 ; https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=24278
 
 ; Make sure we do not crash when dealing with a vector constant expression.
-define <4 x ptr> @test(ptr %ptr) {
+define <4 x ptr> @test(ptr %ptr) null_pointer_is_valid {
 ; CHECK-LABEL: @test(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[L3:%.*]] = load i64, ptr [[PTR:%.*]], align 4

llvm/test/Transforms/InstCombine/getelementptr.ll

@@ -1326,40 +1326,6 @@ define ptr @PR45084_extra_use(i1 %cond, ptr %p) {
   ret ptr %sel
 }
 
-define ptr @gep_null_inbounds(i64 %idx) {
-; CHECK-LABEL: @gep_null_inbounds(
-; CHECK-NEXT:    ret ptr null
-;
-  %gep = getelementptr inbounds i8, ptr null, i64 %idx
-  ret ptr %gep
-}
-
-define ptr @gep_null_not_inbounds(i64 %idx) {
-; CHECK-LABEL: @gep_null_not_inbounds(
-; CHECK-NEXT:    [[GEP:%.*]] = getelementptr i8, ptr null, i64 [[IDX:%.*]]
-; CHECK-NEXT:    ret ptr [[GEP]]
-;
-  %gep = getelementptr i8, ptr null, i64 %idx
-  ret ptr %gep
-}
-
-define ptr @gep_null_defined(i64 %idx) null_pointer_is_valid {
-; CHECK-LABEL: @gep_null_defined(
-; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i8, ptr null, i64 [[IDX:%.*]]
-; CHECK-NEXT:    ret ptr [[GEP]]
-;
-  %gep = getelementptr inbounds i8, ptr null, i64 %idx
-  ret ptr %gep
-}
-
-define ptr @gep_null_inbounds_different_type(i64 %idx1, i64 %idx2) {
-; CHECK-LABEL: @gep_null_inbounds_different_type(
-; CHECK-NEXT:    ret ptr null
-;
-  %gep = getelementptr inbounds [0 x i8], ptr null, i64 %idx1, i64 %idx2
-  ret ptr %gep
-}
-
 define ptr @D98588(ptr %c1, i64 %offset) {
 ; CHECK-LABEL: @D98588(
 ; CHECK-NEXT:    [[C2_NEXT_IDX:%.*]] = shl nsw i64 [[OFFSET:%.*]], 3
@@ -2017,38 +1983,4 @@ define ptr @gep_merge_nusw_const(ptr %p, i64 %idx, i64 %idx2) {
   ret ptr %gep
 }
 
-define <2 x ptr> @gep_inbounds_null_vec(i64 %idx) {
-; CHECK-LABEL: @gep_inbounds_null_vec(
-; CHECK-NEXT:    ret <2 x ptr> zeroinitializer
-;
-  %p = getelementptr inbounds i8, <2 x ptr> zeroinitializer, i64 %idx
-  ret <2 x ptr> %p
-}
-
-define <2 x ptr> @gep_inbounds_null_vec_broadcast(<2 x i64> %idx) {
-; CHECK-LABEL: @gep_inbounds_null_vec_broadcast(
-; CHECK-NEXT:    ret <2 x ptr> zeroinitializer
-;
-  %p = getelementptr inbounds i8, ptr null, <2 x i64> %idx
-  ret <2 x ptr> %p
-}
-
-define ptr @gep_noinbounds_null(i64 %idx) {
-; CHECK-LABEL: @gep_noinbounds_null(
-; CHECK-NEXT:    [[P:%.*]] = getelementptr i8, ptr null, i64 [[IDX:%.*]]
-; CHECK-NEXT:    ret ptr [[P]]
-;
-  %p = getelementptr i8, ptr null, i64 %idx
-  ret ptr %p
-}
-
-define ptr @gep_inbounds_null_null_is_valid(i64 %idx) null_pointer_is_valid {
-; CHECK-LABEL: @gep_inbounds_null_null_is_valid(
-; CHECK-NEXT:    [[P:%.*]] = getelementptr inbounds i8, ptr null, i64 [[IDX:%.*]]
-; CHECK-NEXT:    ret ptr [[P]]
-;
-  %p = getelementptr inbounds i8, ptr null, i64 %idx
-  ret ptr %p
-}
-
 !0 = !{!"branch_weights", i32 2, i32 10}

llvm/test/Transforms/InstSimplify/ConstProp/cast-vector.ll

@@ -5,7 +5,7 @@
 ; "offsetof-like expression" case).
 ; This used to hit an assert due to not supporting vectors in
 ; llvm::ConstantFoldCastInstruction when handling ptrtoint.
-define <2 x i16> @test1() {
+define <2 x i16> @test1() null_pointer_is_valid {
 ; CHECK-LABEL: @test1(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    ret <2 x i16> <i16 ptrtoint (ptr getelementptr inbounds ([10 x i32], ptr null, i64 0, i64 5) to i16), i16 ptrtoint (ptr getelementptr inbounds ([10 x i32], ptr null, i64 0, i64 7) to i16)>
@@ -20,7 +20,7 @@ entry:
 ; "sizeof-like expression" case).
 ; This used to hit an assert due to not supporting vectors in
 ; llvm::ConstantFoldCastInstruction when handling ptrtoint.
-define <2 x i16> @test2() {
+define <2 x i16> @test2() null_pointer_is_valid {
 ; CHECK-LABEL: @test2(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    ret <2 x i16> <i16 ptrtoint (ptr getelementptr (i32, ptr null, i64 5) to i16), i16 ptrtoint (ptr getelementptr (i32, ptr null, i64 7) to i16)>