[llvm] r338073 - [SCEV] Don't expand Wrap predicate using inttoptr in ni addrspaces

Thu Jul 26 17:16:27 PDT 2018

Out of curiosity, is there a reason not to always prefer the GEP form 
for any pointer type, not just NI ones?  Seems like they should be 
equally optimizeable.

On 07/26/2018 02:55 PM, Keno Fischer via llvm-commits wrote:
> Author: kfischer
> Date: Thu Jul 26 14:55:06 2018
> New Revision: 338073
>
> URL: http://llvm.org/viewvc/llvm-project?rev=338073&view=rev
> Log:
> [SCEV] Don't expand Wrap predicate using inttoptr in ni addrspaces
>
> Summary:
> In non-integral address spaces, we're not allowed to introduce inttoptr/ptrtoint
> intrinsics. Instead, we need to expand any pointer arithmetic as geps on the
> base pointer. Luckily this is a common task for SCEV, so all we have to do here
> is hook up the corresponding helper function and add test case.
>
> Fixes PR38290
>
> Reviewers: sanjoy
> Differential Revision: https://reviews.llvm.org/D49832
>
> Added:
>      llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-ni.ll
> Modified:
>      llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
>      llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll
>
> Modified: llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp?rev=338073&r1=338072&r2=338073&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp (original)
> +++ llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp Thu Jul 26 14:55:06 2018
> @@ -2159,8 +2159,9 @@ Value *SCEVExpander::generateOverflowChe
>     const SCEV *Step = AR->getStepRecurrence(SE);
>     const SCEV *Start = AR->getStart();
>   
> +  Type *ARTy = AR->getType();
>     unsigned SrcBits = SE.getTypeSizeInBits(ExitCount->getType());
> -  unsigned DstBits = SE.getTypeSizeInBits(AR->getType());
> +  unsigned DstBits = SE.getTypeSizeInBits(ARTy);
>   
>     // The expression {Start,+,Step} has nusw/nssw if
>     //   Step < 0, Start - |Step| * Backedge <= Start
> @@ -2172,11 +2173,12 @@ Value *SCEVExpander::generateOverflowChe
>     Value *TripCountVal = expandCodeFor(ExitCount, CountTy, Loc);
>   
>     IntegerType *Ty =
> -      IntegerType::get(Loc->getContext(), SE.getTypeSizeInBits(AR->getType()));
> +      IntegerType::get(Loc->getContext(), SE.getTypeSizeInBits(ARTy));
> +  Type *ARExpandTy = DL.isNonIntegralPointerType(ARTy) ? ARTy : Ty;
>   
>     Value *StepValue = expandCodeFor(Step, Ty, Loc);
>     Value *NegStepValue = expandCodeFor(SE.getNegativeSCEV(Step), Ty, Loc);
> -  Value *StartValue = expandCodeFor(Start, Ty, Loc);
> +  Value *StartValue = expandCodeFor(Start, ARExpandTy, Loc);
>   
>     ConstantInt *Zero =
>         ConstantInt::get(Loc->getContext(), APInt::getNullValue(DstBits));
> @@ -2199,8 +2201,18 @@ Value *SCEVExpander::generateOverflowChe
>     // Compute:
>     //   Start + |Step| * Backedge < Start
>     //   Start - |Step| * Backedge > Start
> -  Value *Add = Builder.CreateAdd(StartValue, MulV);
> -  Value *Sub = Builder.CreateSub(StartValue, MulV);
> +  Value *Add = nullptr, *Sub = nullptr;
> +  if (PointerType *ARPtrTy = dyn_cast<PointerType>(ARExpandTy)) {
> +    const SCEV *MulS = SE.getSCEV(MulV);
> +    const SCEV *NegMulS = SE.getNegativeSCEV(MulS);
> +    Add = Builder.CreateBitCast(expandAddToGEP(MulS, ARPtrTy, Ty, StartValue),
> +                                ARPtrTy);
> +    Sub = Builder.CreateBitCast(
> +        expandAddToGEP(NegMulS, ARPtrTy, Ty, StartValue), ARPtrTy);
> +  } else {
> +    Add = Builder.CreateAdd(StartValue, MulV);
> +    Sub = Builder.CreateSub(StartValue, MulV);
> +  }
>   
>     Value *EndCompareGT = Builder.CreateICmp(
>         Signed ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT, Sub, StartValue);
>
> Added: llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-ni.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-ni.ll?rev=338073&view=auto
> ==============================================================================
> --- llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-ni.ll (added)
> +++ llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-ni.ll Thu Jul 26 14:55:06 2018
> @@ -0,0 +1,54 @@
> +; RUN: opt -loop-versioning -S < %s | FileCheck %s -check-prefix=LV
> +
> +; NB: addrspaces 10-13 are non-integral
> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:10:11:12:13"
> +
> +; This matches the test case from PR38290
> +; Check that we expand the SCEV predicate check using GEP, rather
> +; than ptrtoint.
> +
> +%jl_value_t = type opaque
> +%jl_array_t = type { i8 addrspace(13)*, i64, i16, i16, i32 }
> +
> +declare i64 @julia_steprange_last_4949()
> +
> +define void @"japi1_align!_9477"(%jl_value_t addrspace(10)** %arg) {
> +; LV-LAVEL: L26.lver.check
> +; LV: [[OFMul:%[^ ]*]]  = call { i64, i1 } @llvm.umul.with.overflow.i64(i64 4, i64 [[Step:%[^ ]*]])
> +; LV-NEXT: [[OFMulResult:%[^ ]*]] = extractvalue { i64, i1 } [[OFMul]], 0
> +; LV-NEXT: [[OFMulOverflow:%[^ ]*]] = extractvalue { i64, i1 } [[OFMul]], 1
> +; LV-NEXT: [[PosGEP:%[^ ]*]] = getelementptr i32, i32 addrspace(13)* [[Base:%[^ ]*]], i64 [[Step]]
> +; LV-NEXT: [[NegGEP:%[^ ]*]] = getelementptr i32, i32 addrspace(13)* [[Base]], i64 [[NegStep:%[^ ]*]]
> +; LV-NEXT: icmp ugt i32 addrspace(13)* [[NegGEP]], [[Base]]
> +; LV-NEXT: icmp ult i32 addrspace(13)* [[PosGEP]], [[Base]]
> +; LV-NOT: inttoptr
> +; LV-NOT: ptrtoint
> +top:
> +  %tmp = load %jl_value_t addrspace(10)*, %jl_value_t addrspace(10)** %arg, align 8
> +  %tmp1 = load i32, i32* inttoptr (i64 12 to i32*), align 4
> +  %tmp2 = sub i32 0, %tmp1
> +  %tmp3 = call i64 @julia_steprange_last_4949()
> +  %tmp4 = addrspacecast %jl_value_t addrspace(10)* %tmp to %jl_value_t addrspace(11)*
> +  %tmp5 = bitcast %jl_value_t addrspace(11)* %tmp4 to %jl_value_t addrspace(10)* addrspace(11)*
> +  %tmp6 = load %jl_value_t addrspace(10)*, %jl_value_t addrspace(10)* addrspace(11)* %tmp5, align 8
> +  %tmp7 = addrspacecast %jl_value_t addrspace(10)* %tmp6 to %jl_value_t addrspace(11)*
> +  %tmp8 = bitcast %jl_value_t addrspace(11)* %tmp7 to i32 addrspace(13)* addrspace(11)*
> +  %tmp9 = load i32 addrspace(13)*, i32 addrspace(13)* addrspace(11)* %tmp8, align 8
> +  %tmp10 = sext i32 %tmp2 to i64
> +  br label %L26
> +
> +L26:
> +  %value_phi3 = phi i64 [ 0, %top ], [ %tmp11, %L26 ]
> +  %tmp11 = add i64 %value_phi3, -1
> +  %tmp12 = getelementptr inbounds i32, i32 addrspace(13)* %tmp9, i64 %tmp11
> +  %tmp13 = load i32, i32 addrspace(13)* %tmp12, align 4
> +  %tmp14 = add i64 %tmp11, %tmp10
> +  %tmp15 = getelementptr inbounds i32, i32 addrspace(13)* %tmp9, i64 %tmp14
> +  store i32 %tmp13, i32 addrspace(13)* %tmp15, align 4
> +  %tmp16 = icmp eq i64 %value_phi3, %tmp3
> +  br i1 %tmp16, label %L45, label %L26
> +
> +L45:
> +  ret void
> +}
> +
>
> Modified: llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll?rev=338073&r1=338072&r2=338073&view=diff
> ==============================================================================
> --- llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll (original)
> +++ llvm/trunk/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll Thu Jul 26 14:55:06 2018
> @@ -58,10 +58,10 @@ target datalayout = "e-m:o-i64:64-f80:12
>   ; LV-NEXT: [[OFMul1:%[^ ]*]] = call { i64, i1 } @llvm.umul.with.overflow.i64(i64 4, i64 [[BE]])
>   ; LV-NEXT: [[OFMulResult1:%[^ ]*]] = extractvalue { i64, i1 } [[OFMul1]], 0
>   ; LV-NEXT: [[OFMulOverflow1:%[^ ]*]] = extractvalue { i64, i1 } [[OFMul1]], 1
> -; LV-NEXT: [[AddEnd1:%[^ ]*]] = add i64 %a2, [[OFMulResult1]]
> -; LV-NEXT: [[SubEnd1:%[^ ]*]] = sub i64 %a2, [[OFMulResult1]]
> -; LV-NEXT: [[CmpNeg1:%[^ ]*]] = icmp ugt i64 [[SubEnd1]], %a2
> -; LV-NEXT: [[CmpPos1:%[^ ]*]] = icmp ult i64 [[AddEnd1]], %a2
> +; LV-NEXT: [[AddEnd1:%[^ ]*]] = add i64 [[A0:%[^ ]*]], [[OFMulResult1]]
> +; LV-NEXT: [[SubEnd1:%[^ ]*]] = sub i64 [[A0]], [[OFMulResult1]]
> +; LV-NEXT: [[CmpNeg1:%[^ ]*]] = icmp ugt i64 [[SubEnd1]], [[A0]]
> +; LV-NEXT: [[CmpPos1:%[^ ]*]] = icmp ult i64 [[AddEnd1]], [[A0]]
>   ; LV-NEXT: [[Cmp:%[^ ]*]] = select i1 false, i1 [[CmpNeg1]], i1 [[CmpPos1]]
>   ; LV-NEXT: [[PredCheck1:%[^ ]*]] = or i1 [[Cmp]], [[OFMulOverflow1]]
>   
> @@ -233,10 +233,10 @@ for.end:
>   ; LV: [[OFMul1:%[^ ]*]] = call { i64, i1 } @llvm.umul.with.overflow.i64(i64 4, i64 [[BE:%[^ ]*]])
>   ; LV-NEXT: [[OFMulResult1:%[^ ]*]] = extractvalue { i64, i1 } [[OFMul1]], 0
>   ; LV-NEXT: [[OFMulOverflow1:%[^ ]*]] = extractvalue { i64, i1 } [[OFMul1]], 1
> -; LV-NEXT: [[AddEnd1:%[^ ]*]] = add i64 %a2, [[OFMulResult1]]
> -; LV-NEXT: [[SubEnd1:%[^ ]*]] = sub i64 %a2, [[OFMulResult1]]
> -; LV-NEXT: [[CmpNeg1:%[^ ]*]] = icmp ugt i64 [[SubEnd1]], %a2
> -; LV-NEXT: [[CmpPos1:%[^ ]*]] = icmp ult i64 [[AddEnd1]], %a2
> +; LV-NEXT: [[AddEnd1:%[^ ]*]] = add i64 [[A0:%[^ ]*]], [[OFMulResult1]]
> +; LV-NEXT: [[SubEnd1:%[^ ]*]] = sub i64 [[A0]], [[OFMulResult1]]
> +; LV-NEXT: [[CmpNeg1:%[^ ]*]] = icmp ugt i64 [[SubEnd1]], [[A0]]
> +; LV-NEXT: [[CmpPos1:%[^ ]*]] = icmp ult i64 [[AddEnd1]], [[A0]]
>   ; LV-NEXT: [[Cmp:%[^ ]*]] = select i1 false, i1 [[CmpNeg1]], i1 [[CmpPos1]]
>   ; LV-NEXT: [[PredCheck1:%[^ ]*]] = or i1 [[Cmp]], [[OFMulOverflow1]]
>   
>
>
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