From a91fd0998fcf39b8eb1920f358671cbe82b0ef1c Mon Sep 17 00:00:00 2001 From: Bjorn Steinbrink Date: Fri, 10 Jul 2015 06:55:44 +0000 Subject: [InstCombine] Properly combine metadata when replacing a load with another Not doing this can lead to misoptimizations down the line, e.g. because of range metadata on the replacing load excluding values that are valid for the load that is being replaced. llvm-svn: 241886 --- .../InstCombine/InstCombineLoadStoreAlloca.cpp | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp index e7a45330d95..224e3321926 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp @@ -749,10 +749,27 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) { // where there are several consecutive memory accesses to the same location, // separated by a few arithmetic operations. BasicBlock::iterator BBI = &LI; - if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,6)) + AAMDNodes AATags; + if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI, + 6, nullptr, &AATags)) { + if (LoadInst *NLI = dyn_cast(AvailableVal)) { + unsigned KnownIDs[] = { + LLVMContext::MD_tbaa, + LLVMContext::MD_alias_scope, + LLVMContext::MD_noalias, + LLVMContext::MD_range, + LLVMContext::MD_invariant_load, + LLVMContext::MD_nonnull, + }; + combineMetadata(NLI, &LI, KnownIDs); + if (AATags) + NLI->setAAMetadata(AATags); + }; + return ReplaceInstUsesWith( LI, Builder->CreateBitOrPointerCast(AvailableVal, LI.getType(), LI.getName() + ".cast")); + } // load(gep null, ...) -> unreachable if (GetElementPtrInst *GEPI = dyn_cast(Op)) { -- cgit v1.2.3