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Improve the NullCheckElimination pass #14
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r? @pcwalton |
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| enum CmpPred { | ||
| CmpEq, | ||
| CmpNe, |
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I didn't know that trailing commas were legal in C++ like this. Huh.
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Looks good modulo a few nits. |
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or rather, one nit. |
Teach the NullCheckElimination pass about recurrences involving inbounds GEPs. This allows the pass to optimize null checks from most uses of single slice and vector iterators. This still isn't sufficient to eliminate null checks from uses of multiple iterators with zip().
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I rebased to mention that the passes responsible for the canonicalization are InstCombine / InstSimplify. Regarding your second nit, just in case GitHub loses it in the rebase I had this comment: I don't actually rely on this assumption in the |
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Sorry this fell under the radar! Merged as https://github.com/rust-lang/llvm/tree/rust-llvm-2014-07-20. In the future feel free to ping me about merging these. |
alexcrichton
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Aug 2, 2018
This reverts commit r337504 while I investigate a TSan bot failure that seems related: http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-autoconf/builds/26526 #8 0x000055581f2895d8 (/b/sanitizer-x86_64-linux-autoconf/build/tsan_debug_build/bin/clang-7+0x1eb45d8) #9 0x000055581f294323 llvm::ConstantAggrKeyType<llvm::ConstantArray>::create(llvm::ArrayType*) const /b/sanitizer-x86_64-linux-autoconf/build/llvm/lib/IR/ConstantsContext.h:409:0 #10 0x000055581f294323 llvm::ConstantUniqueMap<llvm::ConstantArray>::create(llvm::ArrayType*, llvm::ConstantAggrKeyType<llvm::ConstantArray>, std::pair<unsigned int, std::pair<llvm::ArrayType*, llvm::ConstantAggrKeyType<llvm::ConstantArray> > >&) /b/sanitizer-x86_64-linux-autoconf/build/llvm/lib/IR/ConstantsContext.h:635:0 #11 0x000055581f294323 llvm::ConstantUniqueMap<llvm::ConstantArray>::getOrCreate(llvm::ArrayType*, llvm::ConstantAggrKeyType<llvm::ConstantArray>) /b/sanitizer-x86_64-linux-autoconf/build/llvm/lib/IR/ConstantsContext.h:654:0 #12 0x000055581f2944cb llvm::ConstantArray::get(llvm::ArrayType*, llvm::ArrayRef<llvm::Constant*>) /b/sanitizer-x86_64-linux-autoconf/build/llvm/lib/IR/Constants.cpp:964:0 #13 0x000055581fa27e19 llvm::SmallVectorBase::size() const /b/sanitizer-x86_64-linux-autoconf/build/llvm/include/llvm/ADT/SmallVector.h:53:0 #14 0x000055581fa27e19 llvm::SmallVectorImpl<llvm::Constant*>::resize(unsigned long) /b/sanitizer-x86_64-linux-autoconf/build/llvm/include/llvm/ADT/SmallVector.h:347:0 #15 0x000055581fa27e19 (anonymous namespace)::EmitArrayConstant(clang::CodeGen::CodeGenModule&, clang::ConstantArrayType const*, llvm::Type*, unsigned int, llvm::SmallVectorImpl<llvm::Constant*>&, llvm::Constant*) /b/sanitizer-x86_64-linux-autoconf/build/llvm/tools/clang/lib/CodeGen/CGExprConstant.cpp:669:0 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337511 91177308-0d34-0410-b5e6-96231b3b80d8
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Teach the NullCheckElimination pass about recurrences involving inbounds
GEPs. This allows the pass to optimize null checks from most uses of
single slice and vector iterators.
This still isn't sufficient to eliminate null checks from uses of
multiple iterators with zip().
I also had my editor set to convert 8 spaces to a tab from a previous
project, so I'm undoing that here.