[llvm] r290844 - [InstCombine] use combineMetadataForCSE instead of copying it; NFCI

[Davide Italiano via llvm-commits]

On Mon, Jan 2, 2017 at 3:25 PM, Sanjay Patel via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: spatel
> Date: Mon Jan  2 17:25:28 2017
> New Revision: 290844
>
> URL: http://llvm.org/viewvc/llvm-project?rev=290844&view=rev
> Log:
> [InstCombine] use combineMetadataForCSE instead of copying it; NFCI
>
> Modified:
>     llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
>
> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp?rev=290844&r1=290843&r2=290844&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp (original)
> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp Mon Jan  2 17:25:28 2017
> @@ -850,20 +850,10 @@ Instruction *InstCombiner::visitLoadInst
>    // separated by a few arithmetic operations.
>    BasicBlock::iterator BBI(LI);
>    bool IsLoadCSE = false;
> -  if (Value *AvailableVal =
> -      FindAvailableLoadedValue(&LI, LI.getParent(), BBI,
> -                               DefMaxInstsToScan, AA, &IsLoadCSE)) {
> -    if (IsLoadCSE) {
> -      LoadInst *NLI = cast<LoadInst>(AvailableVal);
> -      unsigned KnownIDs[] = {
> -          LLVMContext::MD_tbaa,            LLVMContext::MD_alias_scope,
> -          LLVMContext::MD_noalias,         LLVMContext::MD_range,
> -          LLVMContext::MD_invariant_load,  LLVMContext::MD_nonnull,
> -          LLVMContext::MD_invariant_group, LLVMContext::MD_align,
> -          LLVMContext::MD_dereferenceable,
> -          LLVMContext::MD_dereferenceable_or_null};
> -      combineMetadata(NLI, &LI, KnownIDs);
> -    };
> +  if (Value *AvailableVal = FindAvailableLoadedValue(
> +          &LI, LI.getParent(), BBI, DefMaxInstsToScan, AA, &IsLoadCSE)) {
> +    if (IsLoadCSE)
> +      combineMetadataForCSE(cast<LoadInst>(AvailableVal), &LI);
>

We have still a lot of places where we have fundamentally the same'ish
version of this code in the tree
(GVN/GVNHoist/SimplifyCFG/BBVectorize), is it possible to convert to
`combineMetadataForCSE` (or there's some caveat here I'm missing)?

-- 
Davide

"There are no solved problems; there are only problems that are more
or less solved" -- Henri Poincare