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release/20.x: [LAA] Consider accessed addrspace when mapping underlying obj to access. (#129087) #129317

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release/20.x: [LAA] Consider accessed addrspace when mapping underlying obj to access. (#129087) #129317

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12 changes: 8 additions & 4 deletions llvm/lib/Analysis/LoopAccessAnalysis.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1283,8 +1283,10 @@ void AccessAnalysis::processMemAccesses() {

bool SetHasWrite = false;

// Map of pointers to last access encountered.
typedef DenseMap<const Value*, MemAccessInfo> UnderlyingObjToAccessMap;
// Map of (pointer to underlying objects, accessed address space) to last
// access encountered.
typedef DenseMap<std::pair<const Value *, unsigned>, MemAccessInfo>
UnderlyingObjToAccessMap;
UnderlyingObjToAccessMap ObjToLastAccess;

// Set of access to check after all writes have been processed.
Expand Down Expand Up @@ -1364,12 +1366,14 @@ void AccessAnalysis::processMemAccesses() {
UnderlyingObj->getType()->getPointerAddressSpace()))
continue;

unsigned AccessAS = cast<PointerType>(Ptr->getType())->getAddressSpace();
UnderlyingObjToAccessMap::iterator Prev =
ObjToLastAccess.find(UnderlyingObj);
ObjToLastAccess.find({UnderlyingObj,AccessAS
});
if (Prev != ObjToLastAccess.end())
DepCands.unionSets(Access, Prev->second);

ObjToLastAccess[UnderlyingObj] = Access;
ObjToLastAccess[{UnderlyingObj, AccessAS}] = Access;
LLVM_DEBUG(dbgs() << " " << *UnderlyingObj << "\n");
}
}
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39 changes: 39 additions & 0 deletions llvm/test/Analysis/LoopAccessAnalysis/underlying-object-different-address-spaces.ll
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@@ -0,0 +1,39 @@
; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
; RUN: opt -passes='print<access-info>' -disable-output %s 2>&1 | FileCheck %s

target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"

; Test case for https://github.com/llvm/llvm-project/issues/124759. The same
; underlying object is access through pointers with different address spaces.
define void @same_underlying_object_different_address_spaces(ptr %dst1.as1, ptr %dst2.as1) {
; CHECK-LABEL: 'same_underlying_object_different_address_spaces'
; CHECK-NEXT: loop:
; CHECK-NEXT: Report: cannot identify array bounds
; CHECK-NEXT: Dependences:
; CHECK-NEXT: Run-time memory checks:
; CHECK-NEXT: Grouped accesses:
; CHECK-EMPTY:
; CHECK-NEXT: Non vectorizable stores to invariant address were not found in loop.
; CHECK-NEXT: SCEV assumptions:
; CHECK-EMPTY:
; CHECK-NEXT: Expressions re-written:
;
entry:
%alloc = alloca i8, i64 0, align 128
%as3 = addrspacecast ptr %alloc to ptr addrspace(3)
%as4 = addrspacecast ptr %alloc to ptr addrspace(4)
br label %loop

loop:
%iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
store i32 0, ptr addrspace(4) %as4, align 4
store i32 0, ptr %dst1.as1, align 4
%l = load i64, ptr addrspace(3) %as3, align 4
store i64 %l, ptr %dst2.as1, align 4
%iv.next = add i64 %iv, 1
%c = icmp eq i64 %iv.next, 100
br i1 %c, label %loop, label %exit

exit:
ret void
}