[Attributor][FIX] Use right address space to avoid assertion

[jdoerfert]

Summary

When we strip and accumulate constant offsets we need to pick the right
address space such that the offset APInt has the right bit width.

[JonChesterfield]

LG, thanks. I haven't followed the opaque / typeless work, presumably there's some new API one is expected to call for them.

[JonChesterfield]

Ping. If you land this, I can the land D112227 and confirm that it gets through the amdgpu buildbot.

[arsenm]

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

1227–1232

This is only using the type to get the address space, there's nothing bad going on here

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

auto UsePred = [&](const Use &U, bool &Follow) -> bool {
         // improve on that anymore.
         if (PtrOI.Offset == OffsetAndSize::Unknown) {
           UsrOI = PtrOI;
           Follow = true;
           return true;
         }
 
         // Check if the PHI operand is not dependent on the PHI itself.
-        APInt Offset(DL.getIndexTypeSizeInBits(AssociatedValue.getType()), 0);
+        // TODO: This is not great as we look at the pointer type. However, it
+        // is unclear where the Offset size comes from with typeless pointers.
+        APInt Offset(
+            DL.getIndexSizeInBits(CurPtr->getType()->getPointerAddressSpace()),
+            0);
         if (&AssociatedValue == CurPtr->stripAndAccumulateConstantOffsets(
                                     DL, Offset, /* AllowNonInbounds */ true)) {
           if (Offset != PtrOI.Offset) {
             LLVM_DEBUG(dbgs()
                        << "[AAPointerInfo] PHI operand pointer offset mismatch "
                        << *CurPtr << " in " << *Usr << "\n");
             return false;
           }
           return HandlePassthroughUser(Usr, PtrOI, Follow);

llvm/test/Transforms/OpenMP/attributor_pointer_offset_crash.ll

+; RUN: opt < %s -S -passes=openmp-opt
+
+; Verify the address space cast doesn't cause a crash
+
+target datalayout = "e-p:64:64-p1:64:64-p2:32:32-p3:32:32-p4:64:64-p5:32:32-p6:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64-S32-A5-G1-ni:7"
+
+%"struct.(anonymous namespace)::TeamStateTy" = type { %"struct.(anonymous namespace)::ICVStateTy", i32, i8* }
+%"struct.(anonymous namespace)::ICVStateTy" = type { i32, i32, i32, i32, i32, i32 }
+%"struct.(anonymous namespace)::ThreadStateTy" = type { %"struct.(anonymous namespace)::ICVStateTy", %"struct.(anonymous namespace)::ThreadStateTy"* }
+
+@_ZN12_GLOBAL__N_19TeamStateE = internal addrspace(3) global %"struct.(anonymous namespace)::TeamStateTy" undef, align 8
+
+define internal i8* @__kmpc_alloc_shared() {
+lor.lhs.false.i.i:
+  br i1 false, label %_ZN4_OMP5state8lookup32ENS0_9ValueKindEb.exit.i, label %if.then.i44.i.i
+
+if.then.i44.i.i:                                  ; preds = %lor.lhs.false.i.i
+  br label %_ZN4_OMP5state8lookup32ENS0_9ValueKindEb.exit.i
+
+_ZN4_OMP5state8lookup32ENS0_9ValueKindEb.exit.i:  ; preds = %if.then.i44.i.i, %lor.lhs.false.i.i
+  %.pn.i45.i.i = phi i8* [ null, %if.then.i44.i.i ], [ addrspacecast (i8 addrspace(3)* bitcast (%"struct.(anonymous namespace)::TeamStateTy" addrspace(3)* @_ZN12_GLOBAL__N_19TeamStateE to i8 addrspace(3)*) to i8*), %lor.lhs.false.i.i ]
+  %retval.0.in.i.i.i = getelementptr inbounds i8, i8* %.pn.i45.i.i, i64 4
+  %retval.0.i46.i.i = bitcast i8* %retval.0.in.i.i.i to i32*
+  %0 = load i32, i32* %retval.0.i46.i.i, align 4
+  ret i8* null
+}
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 7, !"openmp", i32 50}
+!1 = !{i32 7, !"openmp-device", i32 50}