diff options
author | Vedant Kumar <vsk@apple.com> | 2017-10-03 01:27:26 +0000 |
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committer | Vedant Kumar <vsk@apple.com> | 2017-10-03 01:27:26 +0000 |
commit | 3f7b4f37be57e8120a8f6621c13cbb373a6cb2fc (patch) | |
tree | f7e6d44de7f46c895720650b540d21632e882449 /lib/CodeGen/CGExpr.cpp | |
parent | 9ce2dd4d7e6c33ff7f49556f5b70f246ea204756 (diff) |
[ubsan] Skip alignment checks which are folded away
Don't emit alignment checks which the IR constant folder throws away.
I've tested this out on X86FastISel.cpp. While this doesn't decrease
end-to-end compile-time significantly, it results in 122 fewer type
checks (1% reduction) overall, without adding any real complexity.
Differential Revision: https://reviews.llvm.org/D37544
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@314752 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/CGExpr.cpp')
-rw-r--r-- | lib/CodeGen/CGExpr.cpp | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp index e87c4a9e2e..cd2e8e14bc 100644 --- a/lib/CodeGen/CGExpr.cpp +++ b/lib/CodeGen/CGExpr.cpp @@ -618,6 +618,7 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc, auto PtrToAlloca = dyn_cast<llvm::AllocaInst>(Ptr->stripPointerCastsNoFollowAliases()); + llvm::Value *True = llvm::ConstantInt::getTrue(getLLVMContext()); llvm::Value *IsNonNull = nullptr; bool IsGuaranteedNonNull = SkippedChecks.has(SanitizerKind::Null) || PtrToAlloca; @@ -629,8 +630,7 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc, // The IR builder can constant-fold the null check if the pointer points to // a constant. - IsGuaranteedNonNull = - IsNonNull == llvm::ConstantInt::getTrue(getLLVMContext()); + IsGuaranteedNonNull = IsNonNull == True; // Skip the null check if the pointer is known to be non-null. if (!IsGuaranteedNonNull) { @@ -684,7 +684,8 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc, PtrAsInt, llvm::ConstantInt::get(IntPtrTy, AlignVal - 1)); llvm::Value *Aligned = Builder.CreateICmpEQ(Align, llvm::ConstantInt::get(IntPtrTy, 0)); - Checks.push_back(std::make_pair(Aligned, SanitizerKind::Alignment)); + if (Aligned != True) + Checks.push_back(std::make_pair(Aligned, SanitizerKind::Alignment)); } } |