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[LLVM16][SinkCommonOffsetFromGEP] Detect type mismatch when grouping GEPs
On opaque pointers we could end up with such group: %C = getelementptr inbounds %class.MC_Vector, %class.MC_Vector* %.privateBuffer, i64 0, i32 1 %C2 = getelementptr inbounds %class.MC_Vector, %class.MC_Vector* %.privateBuffer, i64 0, i32 1 %A = getelementptr inbounds %class.MC_Particle, %class.MC_Particle* %.privateBuffer, i64 0, i32 4 %A2 = getelementptr inbounds %class.MC_Particle, %class.MC_Particle* %.privateBuffer, i64 0, i32 4 The problem is that we have type mismatch here, and later, when such group is being processed it tries to access indices that aren't available in given type e.g 8th index of 3 element struct. Such problematic group should be splitted into two different groups and it solves that problem. %C = getelementptr inbounds %class.MC_Vector, %class.MC_Vector* %.privateBuffer, i64 0, i32 1 %C2 = getelementptr inbounds %class.MC_Vector, %class.MC_Vector* %.privateBuffer, i64 0, i32 1 %A = getelementptr inbounds %class.MC_Particle, %class.MC_Particle* %.privateBuffer, i64 0, i32 4 %A2 = getelementptr inbounds %class.MC_Particle, %class.MC_Particle* %.privateBuffer, i64 0, i32 4 This PR adds check which should result in creation of new group instead of the merge with existing group that'd result in mismatched types.
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‎IGC/Compiler/CISACodeGen/SinkCommonOffsetFromGEP.cpp‎

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/*========================== begin_copyright_notice ============================
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3-
Copyright (C) 2022 Intel Corporation
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Copyright (C) 2022-2025 Intel Corporation
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SPDX-License-Identifier: MIT
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@@ -241,6 +241,20 @@ bool DivergentPointersGroups::isBelongedToGroup(const CommonBaseGroup &Group, co
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if (CurGroupFactor[BB].second != Indices)
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return false;
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}
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// Check if types are consistent across all group factors
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for (auto &GF : Group.GroupFactor) {
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auto groupPtrOperandTy = GF.second.first.first;
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if (!groupPtrOperandTy)
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continue;
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for (const auto &Entry : DP.Geps) {
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GetElementPtrInst *GEP = Entry.second.GEP;
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if (GEP->getSourceElementType() != groupPtrOperandTy)
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return false;
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}
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}
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return true;
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}
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‎IGC/Compiler/tests/SinkCommonOffsetFromGEP/GroupsTypeMismatchDetection.ll‎

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;=========================== begin_copyright_notice ============================
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;
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; Copyright (C) 2025 Intel Corporation
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;
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; SPDX-License-Identifier: MIT
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;
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;============================ end_copyright_notice =============================
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; RUN: igc_opt --opaque-pointers %s -S -o - -igc-sink-gep-constant | FileCheck %s
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; On opaque pointers we could end up with such group:
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;
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; %C = getelementptr inbounds %class.MC_Vector, %class.MC_Vector* %.privateBuffer, i64 0, i32 1
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; %C2 = getelementptr inbounds %class.MC_Vector, %class.MC_Vector* %.privateBuffer, i64 0, i32 1
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; %A = getelementptr inbounds %class.MC_Particle, %class.MC_Particle* %.privateBuffer, i64 0, i32 4
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; %A2 = getelementptr inbounds %class.MC_Particle, %class.MC_Particle* %.privateBuffer, i64 0, i32 4
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;
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; The problem is that we have type mismatch here, and later, when such group is being processed it tries
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; to access indices that aren't available in given type e.g 8th index of 3 element struct.
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; Such problematic group should be splitted into two different groups and it solves that problem.
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;
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; %C = getelementptr inbounds %class.MC_Vector, %class.MC_Vector* %.privateBuffer, i64 0, i32 1
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; %C2 = getelementptr inbounds %class.MC_Vector, %class.MC_Vector* %.privateBuffer, i64 0, i32 1
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;
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; %A = getelementptr inbounds %class.MC_Particle, %class.MC_Particle* %.privateBuffer, i64 0, i32 4
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; %A2 = getelementptr inbounds %class.MC_Particle, %class.MC_Particle* %.privateBuffer, i64 0, i32 4
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;
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v16:16:16-v24:32:32-v32:32:32-v48:64:64-v64:64:64-v96:128:128-v128:128:128-v192:256:256-v256:256:256-v512:512:512-v1024:1024:1024-n8:16:32"
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target triple = "spir64-unknown-unknown"
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%class.MC_Particle = type { %class.MC_Vector, %class.MC_Vector, %class.MC_Vector, i64, i64 }
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%class.MC_Vector = type { double, double }
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; CHECK: if.cond:
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; [[GEP0:%.*]] = getelementptr %class.MC_Vector, ptr %.privateBuffer, i64 0
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; [[GEP1:%.*]] = getelementptr %class.MC_Particle, ptr %.privateBuffer, i64 0
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; [[GEP2:%.*]] = getelementptr %class.MC_Particle, ptr %.privateBuffer, i64 0, i32 1
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; CHECK: else.cond:
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; [[GEP3:%.*]] = getelementptr %class.MC_Vector, ptr %.privateBuffer, i64 0
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; [[GEP4:%.*]] = getelementptr %class.MC_Particle, ptr %.privateBuffer, i64 0
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; [[GEP5:%.*]] = getelementptr %class.MC_Particle, ptr %.privateBuffer, i64 0, i32 1
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; [[PHI1:%.*]] = phi ptr [ [[GEP0]], %if.cond ], [ [[GEP3]], %else.cond ]
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; [[PHI2:%.*]] = phi ptr [ [[GEP1]], %if.cond ], [ [[GEP4]], %else.cond ]
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; [[PHI3:%.*]] = phi ptr [ [[GEP2]], %if.cond ], [ [[GEP5]], %else.cond ]
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; CHECK-NOT: error
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define void @f0(ptr %.privateBuffer, i1 %cond) {
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entry:
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br i1 %cond, label %if.cond, label %else.cond
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if.cond:
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%A = getelementptr inbounds %class.MC_Particle, ptr %.privateBuffer, i64 0, i32 4
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%B = getelementptr inbounds %class.MC_Particle, ptr %.privateBuffer, i64 0, i32 1, i32 1
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%C = getelementptr inbounds %class.MC_Vector, ptr %.privateBuffer, i64 0, i32 1
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br label %exit
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else.cond:
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%A2 = getelementptr inbounds %class.MC_Particle, ptr %.privateBuffer, i64 0, i32 4
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%B2 = getelementptr inbounds %class.MC_Particle, ptr %.privateBuffer, i64 0, i32 1, i32 1
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%C2 = getelementptr inbounds %class.MC_Vector, ptr %.privateBuffer, i64 0, i32 1
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br label %exit
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exit:
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%PhiA1 = phi i64* [ %A, %if.cond ], [ %A2, %else.cond ]
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%PhiA2 = phi i64* [ %A, %if.cond ], [ %A2, %else.cond ]
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%PhiB1 = phi i64* [ %B, %if.cond ], [ %B2, %else.cond ]
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%PhiB2 = phi i64* [ %B, %if.cond ], [ %B2, %else.cond ]
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%PhiC1 = phi i64* [ %C, %if.cond ], [ %C2, %else.cond ]
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%PhiC2 = phi i64* [ %C, %if.cond ], [ %C2, %else.cond ]
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%LoadC1 = load i64, i64* %PhiC1, align 4
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%LoadC2 = load i64, i64* %PhiC2, align 4
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%LoadA1 = load i64, i64* %PhiA1, align 4
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%LoadA2 = load i64, i64* %PhiA2, align 4
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%LoadB1 = load i64, i64* %PhiB1, align 4
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%LoadB2 = load i64, i64* %PhiB2, align 4
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ret void
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}

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