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InstCombine: propagate nonNull through assume 

Make assume (load (call|invoke) != null) set nonNull return attribute
for the call and invoke. Also include tests.

Differential Revision: http://reviews.llvm.org/D7107

llvm-svn: 228556
This commit is contained in:
Ramkumar Ramachandra 2015-02-09 01:13:13 +00:00
parent 6d3e840c93
commit a021ee62ca
2 changed files with 45 additions and 1 deletions
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9
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
View File

@ -1081,12 +1081,19 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
cast<Constant>(RHS)->isNullValue()) {
LoadInst* LI = cast<LoadInst>(LHS);
if (isValidAssumeForContext(II, LI, DL, DT)) {
// assume( load (call|invoke) != null ) -> add 'nonnull' return
// attribute
Value *LIOperand = LI->getOperand(0);
if (CallInst *I = dyn_cast<CallInst>(LIOperand))
I->addAttribute(AttributeSet::ReturnIndex, Attribute::NonNull);
else if (InvokeInst *I = dyn_cast<InvokeInst>(LIOperand))
I->addAttribute(AttributeSet::ReturnIndex, Attribute::NonNull);
MDNode *MD = MDNode::get(II->getContext(), None);
LI->setMetadata(LLVMContext::MD_nonnull, MD);
return EraseInstFromFunction(*II);
}
}
// TODO: apply nonnull return attributes to calls and invokes
// TODO: apply range metadata for range check patterns?
}
// If there is a dominating assume with the same condition as this one,

37
llvm/test/Transforms/InstCombine/assume.ll
View File

@ -257,8 +257,45 @@ entry:
; CHECK: call void @llvm.assume
}
declare i32** @id(i32** %a)
; Check that nonnull return attribute is applied to call
define i1 @nonnull5(i32** %a) {
entry:
%idr = call i32** @id(i32** %a)
%load = load i32** %idr
%cmp = icmp ne i32* %load, null
tail call void @llvm.assume(i1 %cmp)
%rval = icmp eq i32* %load, null
ret i1 %rval
; CHECK-LABEL: @nonnull5
; CHECK: call nonnull
; CHECK-NOT: call void @llvm.assume
; CHECK: ret i1 false
}
declare i32 @__personality0(...)
; Check that nonnull return attribute is applied to invoke
define i1 @nonnull6(i32** %a) {
entry:
%idr = invoke i32** @id(i32** %a) to label %norm unwind label %lpad
norm:
%load = load i32** %idr
%cmp = icmp ne i32* %load, null
tail call void @llvm.assume(i1 %cmp)
%rval = icmp eq i32* %load, null
ret i1 %rval
lpad:
%res = landingpad { i8*, i32 } personality i32 (...)* @__personality0 cleanup
resume { i8*, i32 } undef
; CHECK-LABEL: @nonnull6
; CHECK: invoke nonnull
; CHECK-NOT: call void @llvm.assume
; CHECK: ret i1 false
}
attributes #0 = { nounwind uwtable }
attributes #1 = { nounwind }