Teach isKnownNonNull that a nonnull return is not null. Add a test for this case as well as the case of a nonnull attribute (already handled but not tested).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209193 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2014-05-20 05:13:21 +00:00
parent 956583e98e
commit 4bf804fe0d
2 changed files with 22 additions and 0 deletions

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@ -16,6 +16,7 @@
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
@ -2073,6 +2074,10 @@ bool llvm::isKnownNonNull(const Value *V, const TargetLibraryInfo *TLI) {
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
return !GV->hasExternalWeakLinkage();
if (ImmutableCallSite CS = V)
if (CS.paramHasAttr(0, Attribute::NonNull))
return true;
// operator new never returns null.
if (isOperatorNewLikeFn(V, TLI, /*LookThroughBitCast=*/true))
return true;

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@ -866,3 +866,20 @@ define i1 @exact_ashr_sgt_false(i32 %a) {
; CHECK-LABEL: @exact_ashr_sgt_false
; CHECK-NEXT: ret i1 false
}
define i1 @nonnull_arg(i32* nonnull %i) {
%cmp = icmp eq i32* %i, null
ret i1 %cmp
; CHECK-LABEL: @nonnull_arg
; CHECK: ret i1 false
}
declare nonnull i32* @returns_nonnull_helper()
define i1 @returns_nonnull() {
%call = call nonnull i32* @returns_nonnull_helper()
%cmp = icmp eq i32* %call, null
ret i1 %cmp
; CHECK-LABEL: @returns_nonnull
; CHECK: ret i1 false
}