[llvm] r302209 - Update VP prof metadata during inlining.

Philip Reames via llvm-commits llvm-commits at lists.llvm.org
Fri May 5 18:05:14 PDT 2017


Sorry, I think I'm coming into something late here.  What exactly is VP 
metadata?  I have not seen this before and it does not appear to be 
documented in the LangRef.  The latter is a major problem which needs 
fixed ASAP.

Can you give a pointer where the review thread this was introduced in?

Philip

On 05/04/2017 05:47 PM, Dehao Chen via llvm-commits wrote:
> Author: dehao
> Date: Thu May  4 19:47:34 2017
> New Revision: 302209
>
> URL: http://llvm.org/viewvc/llvm-project?rev=302209&view=rev
> Log:
> Update VP prof metadata during inlining.
>
> Summary: r298270 added profile update logic for branch_weights. This patch implements profile update logic for VP prof metadata too.
>
> Reviewers: eraman, tejohnson, davidxl
>
> Reviewed By: eraman
>
> Subscribers: llvm-commits
>
> Differential Revision: https://reviews.llvm.org/D32773
>
> Modified:
>      llvm/trunk/lib/IR/Instruction.cpp
>      llvm/trunk/test/Transforms/Inline/prof-update.ll
>
> Modified: llvm/trunk/lib/IR/Instruction.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Instruction.cpp?rev=302209&r1=302208&r2=302209&view=diff
> ==============================================================================
> --- llvm/trunk/lib/IR/Instruction.cpp (original)
> +++ llvm/trunk/lib/IR/Instruction.cpp Thu May  4 19:47:34 2017
> @@ -625,20 +625,41 @@ void Instruction::updateProfWeight(uint6
>       return;
>   
>     auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
> -  if (!ProfDataName || !ProfDataName->getString().equals("branch_weights"))
> +  if (!ProfDataName || (!ProfDataName->getString().equals("branch_weights") &&
> +                        !ProfDataName->getString().equals("VP")))
>       return;
>   
> -  SmallVector<uint32_t, 4> Weights;
> -  for (unsigned i = 1; i < ProfileData->getNumOperands(); i++) {
> -    // Using APInt::div may be expensive, but most cases should fit in 64 bits.
> -    APInt Val(128, mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i))
> -                       ->getValue()
> -                       .getZExtValue());
> -    Val *= APInt(128, S);
> -    Weights.push_back(Val.udiv(APInt(128, T)).getLimitedValue());
> -  }
>     MDBuilder MDB(getContext());
> -  setMetadata(LLVMContext::MD_prof, MDB.createBranchWeights(Weights));
> +  SmallVector<Metadata *, 3> Vals;
> +  Vals.push_back(ProfileData->getOperand(0));
> +  APInt APS(128, S), APT(128, T);
> +  if (ProfDataName->getString().equals("branch_weights"))
> +    for (unsigned i = 1; i < ProfileData->getNumOperands(); i++) {
> +      // Using APInt::div may be expensive, but most cases should fit 64 bits.
> +      APInt Val(128,
> +                mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i))
> +                    ->getValue()
> +                    .getZExtValue());
> +      Val *= APS;
> +      Vals.push_back(MDB.createConstant(
> +          ConstantInt::get(Type::getInt64Ty(getContext()),
> +                           Val.udiv(APT).getLimitedValue())));
> +    }
> +  else if (ProfDataName->getString().equals("VP"))
> +    for (unsigned i = 1; i < ProfileData->getNumOperands(); i += 2) {
> +      // The first value is the key of the value profile, which will not change.
> +      Vals.push_back(ProfileData->getOperand(i));
> +      // Using APInt::div may be expensive, but most cases should fit 64 bits.
> +      APInt Val(128,
> +                mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i + 1))
> +                    ->getValue()
> +                    .getZExtValue());
> +      Val *= APS;
> +      Vals.push_back(MDB.createConstant(
> +          ConstantInt::get(Type::getInt64Ty(getContext()),
> +                           Val.udiv(APT).getLimitedValue())));
> +    }
> +  setMetadata(LLVMContext::MD_prof, MDNode::get(getContext(), Vals));
>   }
>   
>   void Instruction::setProfWeight(uint64_t W) {
>
> Modified: llvm/trunk/test/Transforms/Inline/prof-update.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/prof-update.ll?rev=302209&r1=302208&r2=302209&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/Inline/prof-update.ll (original)
> +++ llvm/trunk/test/Transforms/Inline/prof-update.ll Thu May  4 19:47:34 2017
> @@ -3,6 +3,7 @@
>   
>   declare void @ext();
>   declare void @ext1();
> + at func = global void ()* null
>   
>   ; CHECK: define void @callee(i32 %n) !prof ![[ENTRY_COUNT:[0-9]*]]
>   define void  @callee(i32 %n) !prof !1 {
> @@ -17,12 +18,16 @@ cond_false:
>   ; ext is cloned and updated.
>   ; CHECK: call void @ext(), !prof ![[COUNT_CALLEE:[0-9]*]]
>     call void @ext(), !prof !2
> +  %f = load void ()*, void ()** @func
> +; CHECK: call void %f(), !prof ![[COUNT_IND_CALLEE:[0-9]*]]
> +  call void %f(), !prof !4
>     ret void
>   }
>   
>   ; CHECK: define void @caller()
>   define void @caller() {
>   ; CHECK: call void @ext(), !prof ![[COUNT_CALLER:[0-9]*]]
> +; CHECK: call void %f.i(), !prof ![[COUNT_IND_CALLER:[0-9]*]]
>     call void @callee(i32 15), !prof !3
>     ret void
>   }
> @@ -32,8 +37,11 @@ define void @caller() {
>   !1 = !{!"function_entry_count", i64 1000}
>   !2 = !{!"branch_weights", i64 2000}
>   !3 = !{!"branch_weights", i64 400}
> +!4 = !{!"VP", i32 0, i64 140, i64 111, i64 80, i64 222, i64 40, i64 333, i64 20}
>   attributes #0 = { alwaysinline }
>   ; CHECK: ![[ENTRY_COUNT]] = !{!"function_entry_count", i64 600}
>   ; CHECK: ![[COUNT_CALLEE1]] = !{!"branch_weights", i64 2000}
> -; CHECK: ![[COUNT_CALLEE]] = !{!"branch_weights", i32 1200}
> -; CHECK: ![[COUNT_CALLER]] = !{!"branch_weights", i32 800}
> +; CHECK: ![[COUNT_CALLEE]] = !{!"branch_weights", i64 1200}
> +; CHECK: ![[COUNT_IND_CALLEE]] = !{!"VP", i32 0, i64 84, i64 111, i64 48, i64 222, i64 24, i64 333, i64 12}
> +; CHECK: ![[COUNT_CALLER]] = !{!"branch_weights", i64 800}
> +; CHECK: ![[COUNT_IND_CALLER]] = !{!"VP", i32 0, i64 56, i64 111, i64 32, i64 222, i64 16, i64 333, i64 8}
>
>
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