[llvm] r247707 - [CorrelatedValuePropagation] Infer nonnull attributes

[Mehdi Amini via llvm-commits]

Hi Igor,

It seems that this broke some clang tests, do you have an ETA on the fix?

Thanks,

— 
Mehdi

> On Sep 15, 2015, at 10:51 AM, Igor Laevsky via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> Author: igor.laevsky
> Date: Tue Sep 15 12:51:50 2015
> New Revision: 247707
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=247707&view=rev
> Log:
> [CorrelatedValuePropagation] Infer nonnull attributes
> 
> LazuValueInfo can prove that value is nonnull based on the context information. 
> Make use of this ability to infer nonnull attributes for the call arguments.
> 
> Differential Revision: http://reviews.llvm.org/D12836
> 
> 
> Modified:
>    llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
>    llvm/trunk/test/Transforms/CorrelatedValuePropagation/non-null.ll
> 
> Modified: llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp?rev=247707&r1=247706&r2=247707&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp (original)
> +++ llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp Tue Sep 15 12:51:50 2015
> @@ -44,6 +44,7 @@ namespace {
>     bool processMemAccess(Instruction *I);
>     bool processCmp(CmpInst *C);
>     bool processSwitch(SwitchInst *SI);
> +    bool processCallSite(CallSite CS);
> 
>   public:
>     static char ID;
> @@ -309,6 +310,32 @@ bool CorrelatedValuePropagation::process
>   return Changed;
> }
> 
> +/// processCallSite - Infer nonnull attributes for the arguments at the
> +/// specified callsite.
> +bool CorrelatedValuePropagation::processCallSite(CallSite CS) {
> +  bool Changed = false;
> +
> +  unsigned ArgNo = 0;
> +  for (Value *V : CS.args()) {
> +    PointerType *Type = dyn_cast<PointerType>(V->getType());
> +
> +    if (Type && !CS.paramHasAttr(ArgNo + 1, Attribute::NonNull) &&
> +        LVI->getPredicateAt(ICmpInst::ICMP_EQ, V,
> +                            ConstantPointerNull::get(Type),
> +                            CS.getInstruction()) == LazyValueInfo::False) {
> +      AttributeSet AS = CS.getAttributes();
> +      AS = AS.addAttribute(CS.getInstruction()->getContext(), ArgNo + 1,
> +                           Attribute::NonNull);
> +      CS.setAttributes(AS);
> +      Changed = true;
> +    }
> +    ArgNo++;
> +  }
> +  assert(ArgNo == CS.arg_size() && "sanity check");
> +
> +  return Changed;
> +}
> +
> bool CorrelatedValuePropagation::runOnFunction(Function &F) {
>   if (skipOptnoneFunction(F))
>     return false;
> @@ -336,6 +363,10 @@ bool CorrelatedValuePropagation::runOnFu
>       case Instruction::Store:
>         BBChanged |= processMemAccess(II);
>         break;
> +      case Instruction::Call:
> +      case Instruction::Invoke:
> +        BBChanged |= processCallSite(CallSite(II));
> +        break;
>       }
>     }
> 
> 
> Modified: llvm/trunk/test/Transforms/CorrelatedValuePropagation/non-null.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/CorrelatedValuePropagation/non-null.ll?rev=247707&r1=247706&r2=247707&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/CorrelatedValuePropagation/non-null.ll (original)
> +++ llvm/trunk/test/Transforms/CorrelatedValuePropagation/non-null.ll Tue Sep 15 12:51:50 2015
> @@ -101,3 +101,42 @@ bb:
> ; CHECK: KEEP2
>   ret void
> }
> +
> +declare void @test10_helper(i8* %arg1, i8* %arg2, i32 %non-pointer-arg)
> +define void @test10(i8* %arg1, i8* %arg2, i32 %non-pointer-arg) {
> +; CHECK-LABEL: @test10
> +entry:
> +  %is_null = icmp eq i8* %arg1, null
> +  br i1 %is_null, label %null, label %non_null
> +
> +non_null:
> +  call void @test10_helper(i8* %arg1, i8* %arg2, i32 %non-pointer-arg)
> +  ; CHECK: call void @test10_helper(i8* nonnull %arg1, i8* %arg2, i32 %non-pointer-arg)
> +  br label %null
> +
> +null:
> +  call void @test10_helper(i8* %arg1, i8* %arg2, i32 %non-pointer-arg)
> +  ; CHECK: call void @test10_helper(i8* %arg1, i8* %arg2, i32 %non-pointer-arg)
> +  ret void
> +}
> +
> +declare void @test11_helper(i8* %arg)
> +define void @test11(i8* %arg1, i8** %arg2) {
> +; CHECK-LABEL: @test11
> +entry:
> +  %is_null = icmp eq i8* %arg1, null
> +  br i1 %is_null, label %null, label %non_null
> +
> +non_null:
> +  br label %merge
> +
> +null:
> +  %another_arg = alloca i8
> +  br label %merge
> +
> +merge:
> +  %merged_arg = phi i8* [%another_arg, %null], [%arg1, %non_null]
> +  call void @test11_helper(i8* %merged_arg)
> +  ; CHECK: call void @test11_helper(i8* nonnull %merged_arg)
> +  ret void
> +}
> 
> 
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