From 77eeac3d9e9418ac0aea131d20ac84b656977814 Mon Sep 17 00:00:00 2001 From: Manoj Gupta Date: Mon, 9 Jul 2018 22:27:23 +0000 Subject: llvm: Add support for "-fno-delete-null-pointer-checks" Summary: Support for this option is needed for building Linux kernel. This is a very frequently requested feature by kernel developers. More details : https://lkml.org/lkml/2018/4/4/601 GCC option description for -fdelete-null-pointer-checks: This Assume that programs cannot safely dereference null pointers, and that no code or data element resides at address zero. -fno-delete-null-pointer-checks is the inverse of this implying that null pointer dereferencing is not undefined. This feature is implemented in LLVM IR in this CL as the function attribute "null-pointer-is-valid"="true" in IR (Under review at D47894). The CL updates several passes that assumed null pointer dereferencing is undefined to not optimize when the "null-pointer-is-valid"="true" attribute is present. Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv Reviewed By: efriedma, george.burgess.iv Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits Differential Revision: https://reviews.llvm.org/D47895 llvm-svn: 336613 --- llvm/lib/Analysis/ConstantFolding.cpp | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'llvm/lib/Analysis/ConstantFolding.cpp') diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp index 38e018f6db0..a49007ee499 100644 --- a/llvm/lib/Analysis/ConstantFolding.cpp +++ b/llvm/lib/Analysis/ConstantFolding.cpp @@ -1589,7 +1589,8 @@ double getValueAsDouble(ConstantFP *Op) { Constant *ConstantFoldScalarCall(StringRef Name, unsigned IntrinsicID, Type *Ty, ArrayRef Operands, - const TargetLibraryInfo *TLI) { + const TargetLibraryInfo *TLI, + ImmutableCallSite CS) { if (Operands.size() == 1) { if (isa(Operands[0])) { // cosine(arg) is between -1 and 1. cosine(invalid arg) is NaN @@ -1603,7 +1604,8 @@ Constant *ConstantFoldScalarCall(StringRef Name, unsigned IntrinsicID, Type *Ty, } if (isa(Operands[0]) && - Operands[0]->getType()->getPointerAddressSpace() == 0) { + !NullPointerIsDefined( + CS.getCaller(), Operands[0]->getType()->getPointerAddressSpace())) { // launder(null) == null == strip(null) iff in addrspace 0 if (IntrinsicID == Intrinsic::launder_invariant_group || IntrinsicID == Intrinsic::strip_invariant_group) @@ -2007,7 +2009,8 @@ Constant *ConstantFoldScalarCall(StringRef Name, unsigned IntrinsicID, Type *Ty, Constant *ConstantFoldVectorCall(StringRef Name, unsigned IntrinsicID, VectorType *VTy, ArrayRef Operands, const DataLayout &DL, - const TargetLibraryInfo *TLI) { + const TargetLibraryInfo *TLI, + ImmutableCallSite CS) { SmallVector Result(VTy->getNumElements()); SmallVector Lane(Operands.size()); Type *Ty = VTy->getElementType(); @@ -2070,7 +2073,7 @@ Constant *ConstantFoldVectorCall(StringRef Name, unsigned IntrinsicID, } // Use the regular scalar folding to simplify this column. - Constant *Folded = ConstantFoldScalarCall(Name, IntrinsicID, Ty, Lane, TLI); + Constant *Folded = ConstantFoldScalarCall(Name, IntrinsicID, Ty, Lane, TLI, CS); if (!Folded) return nullptr; Result[I] = Folded; @@ -2095,9 +2098,9 @@ llvm::ConstantFoldCall(ImmutableCallSite CS, Function *F, if (auto *VTy = dyn_cast(Ty)) return ConstantFoldVectorCall(Name, F->getIntrinsicID(), VTy, Operands, - F->getParent()->getDataLayout(), TLI); + F->getParent()->getDataLayout(), TLI, CS); - return ConstantFoldScalarCall(Name, F->getIntrinsicID(), Ty, Operands, TLI); + return ConstantFoldScalarCall(Name, F->getIntrinsicID(), Ty, Operands, TLI, CS); } bool llvm::isMathLibCallNoop(CallSite CS, const TargetLibraryInfo *TLI) { -- cgit v1.2.3