[llvm] r353129 - [SamplePGO][NFC] Minor improvement to replace a temporary vector with a

[Wei Mi via llvm-commits]

Sorry, I only verified in release build and it didn't complain. Thanks
rtrieu to fix it.

On Mon, Feb 4, 2019 at 6:27 PM Richard Smith <richard at metafoo.co.uk> wrote:

> Hi,
>
> On Mon, 4 Feb 2019 at 16:57, Wei Mi via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> > Author: wmi
> > Date: Mon Feb  4 16:57:50 2019
> > New Revision: 353129
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=353129&view=rev
> > Log:
> > [SamplePGO][NFC] Minor improvement to replace a temporary vector with a
> > brace-enclosed init list.
> >
> > Differential Revision: https://reviews.llvm.org/D57726
> >
> > Modified:
> >     llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp
> >
> > Modified: llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp?rev=353129&r1=353128&r2=353129&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp (original)
> > +++ llvm/trunk/lib/Transforms/IPO/SampleProfile.cpp Mon Feb  4 16:57:50
> 2019
> > @@ -1327,9 +1327,8 @@ void SampleProfileLoader::propagateWeigh
> >                              SortedCallTargets, Sum,
> IPVK_IndirectCallTarget,
> >                              SortedCallTargets.size());
> >          } else if (!dyn_cast<IntrinsicInst>(&I)) {
> > -          SmallVector<uint32_t, 1> Weights;
> > -          Weights.push_back(BlockWeights[BB]);
> > -          I.setMetadata(LLVMContext::MD_prof,
> MDB.createBranchWeights(Weights));
> > +          I.setMetadata(LLVMContext::MD_prof,
> > +                        MDB.createBranchWeights({BlockWeights[BB]}));
>
> This breaks the build with:
>
> lib/Transforms/IPO/SampleProfile.cpp:1331:50: error:
> non-constant-expression cannot be narrowed from type 'unsigned long'
> to 'unsigned int' in initializer list [-Wc++11-narrowing]
>                         MDB.createBranchWeights({BlockWeights[BB]}));
>                                                  ^~~~~~~~~~~~~~~~
> lib/Transforms/IPO/SampleProfile.cpp:1331:50: note: insert an explicit
> cast to silence this issue
>                         MDB.createBranchWeights({BlockWeights[BB]}));
>                                                  ^~~~~~~~~~~~~~~~
>                                                  static_cast<unsigned
> int>( )
>
> This looks like it might be a real bug: BlockWeights allows 64-bit
> weights, whereas createBranchWeights only allows 32-bit weights, so
> there might be data loss here.
>
> >          }
> >        }
> >      }
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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