From ecc1d153b795b9d66529d848225e65c3b6e0b6fb Mon Sep 17 00:00:00 2001 From: Chen Li Date: Mon, 14 Sep 2015 18:10:43 +0000 Subject: [PATCH] [InstCombineCalls] Use isKnownNonNullAt() to check nullness of passing arguments at callsite Summary: This patch replaces isKnownNonNull() with isKnownNonNullAt() when checking nullness of passing arguments at callsite. In this way it can handle cases where the argument does not have nonnull attribute but has a dominating null check from the CFG. It also adds assertions in isKnownNonNull() and isKnownNonNullFromDominatingCondition() to make sure the value checked is pointer type (as defined in LLVM document). These assertions might trip failures in things which are not covered under llvm/test, but fixes should be pretty obvious. Reviewers: reames Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D12779 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247587 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ValueTracking.cpp | 4 ++++ .../InstCombine/InstCombineCalls.cpp | 4 ++-- .../InstCombine/call_nonnull_arg.ll | 20 +++++++++++++++++++ 3 files changed, 26 insertions(+), 2 deletions(-) create mode 100644 test/Transforms/InstCombine/call_nonnull_arg.ll diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 7000210e1fa..21015507d28 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -3220,6 +3220,8 @@ bool llvm::mayBeMemoryDependent(const Instruction &I) { /// Return true if we know that the specified value is never null. bool llvm::isKnownNonNull(const Value *V, const TargetLibraryInfo *TLI) { + assert(V->getType()->isPointerTy() && "V must be pointer type"); + // Alloca never returns null, malloc might. if (isa(V)) return true; @@ -3252,6 +3254,8 @@ bool llvm::isKnownNonNull(const Value *V, const TargetLibraryInfo *TLI) { static bool isKnownNonNullFromDominatingCondition(const Value *V, const Instruction *CtxI, const DominatorTree *DT) { + assert(V->getType()->isPointerTy() && "V must be pointer type"); + unsigned NumUsesExplored = 0; for (auto U : V->users()) { // Avoid massive lists diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp index c5f92a536b7..ad606b03138 100644 --- a/lib/Transforms/InstCombine/InstCombineCalls.cpp +++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp @@ -1583,8 +1583,8 @@ Instruction *InstCombiner::visitCallSite(CallSite CS) { // checks on their arguments. unsigned ArgNo = 0; for (Value *V : CS.args()) { - if (!CS.paramHasAttr(ArgNo+1, Attribute::NonNull) && - isKnownNonNull(V)) { + if (V->getType()->isPointerTy() && !CS.paramHasAttr(ArgNo+1, Attribute::NonNull) && + isKnownNonNullAt(V, CS.getInstruction(), DT, TLI)) { AttributeSet AS = CS.getAttributes(); AS = AS.addAttribute(CS.getInstruction()->getContext(), ArgNo+1, Attribute::NonNull); diff --git a/test/Transforms/InstCombine/call_nonnull_arg.ll b/test/Transforms/InstCombine/call_nonnull_arg.ll new file mode 100644 index 00000000000..b10411f622b --- /dev/null +++ b/test/Transforms/InstCombine/call_nonnull_arg.ll @@ -0,0 +1,20 @@ +; RUN: opt < %s -instcombine -S | FileCheck %s + +; InstCombine should mark null-checked argument as nonnull at callsite +declare void @dummy(i32*, i32) + +define void @test(i32* %a, i32 %b) { +; CHECK-LABEL: @test +; CHECK: call void @dummy(i32* nonnull %a, i32 %b) +entry: + %cond1 = icmp eq i32* %a, null + br i1 %cond1, label %dead, label %not_null +not_null: + %cond2 = icmp eq i32 %b, 0 + br i1 %cond2, label %dead, label %not_zero +not_zero: + call void @dummy(i32* %a, i32 %b) + ret void +dead: + unreachable +} -- 2.34.1