[LAA] Re-check bit-width of pointers after stripping.

[hliao]

Summary

• As the pointer stripping now tracks through addrspacecast, prepare to handle the bit-width difference from the result pointer.

[hliao]

a similar case to https://reviews.llvm.org/D64768

[jdoerfert]

LGTM.

llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp

if (PtrA == PtrB)
     return false;
 
   // Make sure that A and B have the same type if required.
   if (CheckType && PtrA->getType() != PtrB->getType())
     return false;
 
   unsigned IdxWidth = DL.getIndexSizeInBits(ASA);
   Type *Ty = cast<PointerType>(PtrA->getType())->getElementType();
-  APInt Size(IdxWidth, DL.getTypeStoreSize(Ty));
 
   APInt OffsetA(IdxWidth, 0), OffsetB(IdxWidth, 0);
   PtrA = PtrA->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetA);
   PtrB = PtrB->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetB);
 
+  // Retrieve the address space again as pointer stripping now tracks through
+  // `addrspacecast`.
+  ASA = cast<PointerType>(PtrA->getType())->getAddressSpace();
+  ASB = cast<PointerType>(PtrB->getType())->getAddressSpace();
+  // Check that the address spaces match and that the pointers are valid.
+  if (ASA != ASB)
+    return false;
+
+  IdxWidth = DL.getIndexSizeInBits(ASA);
+  OffsetA = OffsetA.sextOrTrunc(IdxWidth);
+  OffsetB = OffsetB.sextOrTrunc(IdxWidth);
+
+  APInt Size(IdxWidth, DL.getTypeStoreSize(Ty));
+
   //  OffsetDelta = OffsetB - OffsetA;
   const SCEV *OffsetSCEVA = SE.getConstant(OffsetA);
   const SCEV *OffsetSCEVB = SE.getConstant(OffsetB);
   const SCEV *OffsetDeltaSCEV = SE.getMinusSCEV(OffsetSCEVB, OffsetSCEVA);
   const SCEVConstant *OffsetDeltaC = dyn_cast<SCEVConstant>(OffsetDeltaSCEV);
   const APInt &OffsetDelta = OffsetDeltaC->getAPInt();
   // Check if they are based on the same pointer. That makes the offsets
   // sufficient.

llvm/trunk/test/Transforms/SLPVectorizer/AMDGPU/address-space-ptr-sze-gep-index-assert.ll

bb:
 
   %sub0 = sub i32 %load.flat.0, %load.lds.0
   %sub1 = sub i32 %load.flat.1, %load.lds.1
 
   store i32 %sub0, i32* undef
   store i32 %sub1, i32* undef
   ret void
 }
+
+; CHECK-LABEL: slp_crash_on_addrspacecast
+; CHECK: ret void
+define void @slp_crash_on_addrspacecast() {
+entry:
+  %0 = getelementptr inbounds i64, i64 addrspace(3)* undef, i32 undef
+  %p0 = addrspacecast i64 addrspace(3)* %0 to i64*
+  store i64 undef, i64* %p0, align 8
+  %1 = getelementptr inbounds i64, i64 addrspace(3)* undef, i32 undef
+  %p1 = addrspacecast i64 addrspace(3)* %1 to i64*
+  store i64 undef, i64* %p1, align 8
+  ret void
+}