This revision was automatically updated to reflect the committed changes.
Closed by commit rGbf7a16a76871: [InlineFunction] Update valid return
attributes at callsite within callee body (authored by anna).
Changed prior to commit:
https://reviews.llvm.org/D76140?vs=254222&id=254573#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D76140/new/
https://reviews.llvm.org/D76140
Files:
llvm/lib/Transforms/Utils/InlineFunction.cpp
llvm/test/Transforms/Inline/ret_attr_update.ll
Index: llvm/test/Transforms/Inline/ret_attr_update.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/Inline/ret_attr_update.ll
@@ -0,0 +1,223 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -inline-threshold=0 -always-inline -S | FileCheck %s
+; RUN: opt < %s -passes=always-inline -S | FileCheck %s
+
+declare i8* @foo(i8*) argmemonly nounwind
+
+define i8* @callee(i8 *%p) alwaysinline {
+; CHECK-LABEL: @callee(
+; CHECK-NEXT: [[R:%.*]] = call i8* @foo(i8* noalias [[P:%.*]])
+; CHECK-NEXT: ret i8* [[R]]
+;
+ %r = call i8* @foo(i8* noalias %p)
+ ret i8* %r
+}
+
+define i8* @caller(i8* %ptr, i64 %x) {
+; CHECK-LABEL: @caller(
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 [[X:%.*]]
+; CHECK-NEXT: [[R_I:%.*]] = call nonnull i8* @foo(i8* noalias [[GEP]])
+; CHECK-NEXT: ret i8* [[R_I]]
+;
+ %gep = getelementptr inbounds i8, i8* %ptr, i64 %x
+ %p = call nonnull i8* @callee(i8* %gep)
+ ret i8* %p
+}
+
+declare void @llvm.experimental.guard(i1,...)
+; Cannot add nonnull attribute to foo
+; because the guard is a throwing call
+define internal i8* @callee_with_throwable(i8* %p) alwaysinline {
+ %r = call i8* @foo(i8* %p)
+ %cond = icmp ne i8* %r, null
+ call void (i1, ...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
+ ret i8* %r
+}
+
+declare i8* @bar(i8*) readonly nounwind
+; Here also we cannot add nonnull attribute to the call bar.
+define internal i8* @callee_with_explicit_control_flow(i8* %p) alwaysinline {
+ %r = call i8* @bar(i8* %p)
+ %cond = icmp ne i8* %r, null
+ br i1 %cond, label %ret, label %orig
+
+ret:
+ ret i8* %r
+
+orig:
+ ret i8* %p
+}
+
+define i8* @caller2(i8* %ptr, i64 %x, i1 %cond) {
+; CHECK-LABEL: @caller2(
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 [[X:%.*]]
+; CHECK-NEXT: [[R_I:%.*]] = call i8* @foo(i8* [[GEP]])
+; CHECK-NEXT: [[COND_I:%.*]] = icmp ne i8* [[R_I]], null
+; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[COND_I]]) [ "deopt"() ]
+; CHECK-NEXT: [[R_I1:%.*]] = call i8* @bar(i8* [[GEP]])
+; CHECK-NEXT: [[COND_I2:%.*]] = icmp ne i8* [[R_I1]], null
+; CHECK-NEXT: br i1 [[COND_I2]], label [[RET_I:%.*]], label [[ORIG_I:%.*]]
+; CHECK: ret.i:
+; CHECK-NEXT: br label [[CALLEE_WITH_EXPLICIT_CONTROL_FLOW_EXIT:%.*]]
+; CHECK: orig.i:
+; CHECK-NEXT: br label [[CALLEE_WITH_EXPLICIT_CONTROL_FLOW_EXIT]]
+; CHECK: callee_with_explicit_control_flow.exit:
+; CHECK-NEXT: [[Q3:%.*]] = phi i8* [ [[R_I1]], [[RET_I]] ], [ [[GEP]], [[ORIG_I]] ]
+; CHECK-NEXT: br i1 [[COND:%.*]], label [[PRET:%.*]], label [[QRET:%.*]]
+; CHECK: pret:
+; CHECK-NEXT: ret i8* [[R_I]]
+; CHECK: qret:
+; CHECK-NEXT: ret i8* [[Q3]]
+;
+ %gep = getelementptr inbounds i8, i8* %ptr, i64 %x
+ %p = call nonnull i8* @callee_with_throwable(i8* %gep)
+ %q = call nonnull i8* @callee_with_explicit_control_flow(i8* %gep)
+ br i1 %cond, label %pret, label %qret
+
+pret:
+ ret i8* %p
+
+qret:
+ ret i8* %q
+}
+
+define internal i8* @callee3(i8 *%p) alwaysinline {
+ %r = call noalias i8* @foo(i8* %p)
+ ret i8* %r
+}
+
+; add the deref attribute to the existing attributes on foo.
+define i8* @caller3(i8* %ptr, i64 %x) {
+; CHECK-LABEL: @caller3(
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 [[X:%.*]]
+; CHECK-NEXT: [[R_I:%.*]] = call noalias dereferenceable_or_null(12) i8* @foo(i8* [[GEP]])
+; CHECK-NEXT: ret i8* [[R_I]]
+;
+ %gep = getelementptr inbounds i8, i8* %ptr, i64 %x
+ %p = call dereferenceable_or_null(12) i8* @callee3(i8* %gep)
+ ret i8* %p
+}
+
+declare i8* @inf_loop_call(i8*) nounwind
+; We cannot propagate attributes to foo because we do not know whether inf_loop_call
+; will return execution.
+define internal i8* @callee_with_sideeffect_callsite(i8* %p) alwaysinline {
+ %r = call i8* @foo(i8* %p)
+ %v = call i8* @inf_loop_call(i8* %p)
+ ret i8* %r
+}
+
+; do not add deref attribute to foo
+define i8* @test4(i8* %ptr, i64 %x) {
+; CHECK-LABEL: @test4(
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 [[X:%.*]]
+; CHECK-NEXT: [[R_I:%.*]] = call i8* @foo(i8* [[GEP]])
+; CHECK-NEXT: [[V_I:%.*]] = call i8* @inf_loop_call(i8* [[GEP]])
+; CHECK-NEXT: ret i8* [[R_I]]
+;
+ %gep = getelementptr inbounds i8, i8* %ptr, i64 %x
+ %p = call dereferenceable_or_null(12) i8* @callee_with_sideeffect_callsite(i8* %gep)
+ ret i8* %p
+}
+
+declare i8* @baz(i8*) nounwind readonly
+define internal i8* @callee5(i8* %p) alwaysinline {
+ %r = call i8* @foo(i8* %p)
+ %v = call i8* @baz(i8* %p)
+ ret i8* %r
+}
+
+; add the deref attribute to foo.
+define i8* @test5(i8* %ptr, i64 %x) {
+; CHECK-LABEL: @test5(
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 [[X:%.*]]
+; CHECK-NEXT: [[R_I:%.*]] = call dereferenceable_or_null(12) i8* @foo(i8* [[GEP]])
+; CHECK-NEXT: [[V_I:%.*]] = call i8* @baz(i8* [[GEP]])
+; CHECK-NEXT: ret i8* [[R_I]]
+;
+ %gep = getelementptr inbounds i8, i8* %ptr, i64 %x
+ %s = call dereferenceable_or_null(12) i8* @callee5(i8* %gep)
+ ret i8* %s
+}
+
+; deref attributes have different values on the callee and the call feeding into
+; the return.
+; AttrBuilder chooses the already existing value and does not overwrite it.
+define internal i8* @callee6(i8* %p) alwaysinline {
+ %r = call dereferenceable_or_null(16) i8* @foo(i8* %p)
+ %v = call i8* @baz(i8* %p)
+ ret i8* %r
+}
+
+
+define i8* @test6(i8* %ptr, i64 %x) {
+; CHECK-LABEL: @test6(
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 [[X:%.*]]
+; CHECK-NEXT: [[R_I:%.*]] = call dereferenceable_or_null(16) i8* @foo(i8* [[GEP]])
+; CHECK-NEXT: [[V_I:%.*]] = call i8* @baz(i8* [[GEP]])
+; CHECK-NEXT: ret i8* [[R_I]]
+;
+ %gep = getelementptr inbounds i8, i8* %ptr, i64 %x
+ %s = call dereferenceable_or_null(12) i8* @callee6(i8* %gep)
+ ret i8* %s
+}
+
+; We add the attributes from the callee to both the calls below.
+define internal i8* @callee7(i8 *%ptr, i1 %cond) alwaysinline {
+ br i1 %cond, label %pass, label %fail
+
+pass:
+ %r = call i8* @foo(i8* noalias %ptr)
+ ret i8* %r
+
+fail:
+ %s = call i8* @baz(i8* %ptr)
+ ret i8* %s
+}
+
+define void @test7(i8* %ptr, i64 %x, i1 %cond) {
+; CHECK-LABEL: @test7(
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 [[X:%.*]]
+; CHECK-NEXT: br i1 [[COND:%.*]], label [[PASS_I:%.*]], label [[FAIL_I:%.*]]
+; CHECK: pass.i:
+; CHECK-NEXT: [[R_I:%.*]] = call nonnull i8* @foo(i8* noalias [[GEP]])
+; CHECK-NEXT: br label [[CALLEE7_EXIT:%.*]]
+; CHECK: fail.i:
+; CHECK-NEXT: [[S_I:%.*]] = call nonnull i8* @baz(i8* [[GEP]])
+; CHECK-NEXT: br label [[CALLEE7_EXIT]]
+; CHECK: callee7.exit:
+; CHECK-NEXT: [[T1:%.*]] = phi i8* [ [[R_I]], [[PASS_I]] ], [ [[S_I]], [[FAIL_I]] ]
+; CHECK-NEXT: call void @snort(i8* [[T1]])
+; CHECK-NEXT: ret void
+;
+
+ %gep = getelementptr inbounds i8, i8* %ptr, i64 %x
+ %t = call nonnull i8* @callee7(i8* %gep, i1 %cond)
+ call void @snort(i8* %t)
+ ret void
+}
+declare void @snort(i8*)
+
+declare i32 @intrinsic(i8*) nounwind argmemonly
+
+define internal i32 @callee8(i8* %ptr) alwaysinline {
+ %r = call i32 @intrinsic(i8* noalias %ptr)
+ ret i32 %r
+}
+
+
+; signext is an attribute specific to the target ABI and not the
+; callee/callsite.
+; We cannot propagate that attribute to another call since it can be invalid at
+; that call.
+define i32 @test8(i8* %ptr, i64 %x) {
+; CHECK-LABEL: @test8(
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, i8* [[PTR:%.*]], i64 [[X:%.*]]
+; CHECK-NEXT: [[R_I:%.*]] = call i32 @intrinsic(i8* noalias [[GEP]])
+; CHECK-NEXT: ret i32 [[R_I]]
+;
+
+ %gep = getelementptr inbounds i8, i8* %ptr, i64 %x
+ %t = call signext i32 @callee8(i8* %gep)
+ ret i32 %t
+}
Index: llvm/lib/Transforms/Utils/InlineFunction.cpp
===================================================================
--- llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -85,6 +85,16 @@
cl::init(true), cl::Hidden,
cl::desc("Convert align attributes to assumptions during inlining."));
+static cl::opt<bool> UpdateReturnAttributes(
+ "update-return-attrs", cl::init(true), cl::Hidden,
+ cl::desc("Update return attributes on calls within inlined body"));
+
+static cl::opt<unsigned> InlinerAttributeWindow(
+ "max-inst-checked-for-throw-during-inlining", cl::Hidden,
+ cl::desc("the maximum number of instructions analyzed for may throw during "
+ "attribute inference in inlined body"),
+ cl::init(4));
+
llvm::InlineResult llvm::InlineFunction(CallBase *CB, InlineFunctionInfo &IFI,
AAResults *CalleeAAR,
bool InsertLifetime) {
@@ -1136,6 +1146,97 @@
}
}
+static bool MayContainThrowingOrExitingCall(Instruction *Begin,
+ Instruction *End) {
+
+ assert(Begin->getParent() == End->getParent() &&
+ "Expected to be in same basic block!");
+ unsigned NumInstChecked = 0;
+ // Check that all instructions in the range [Begin, End) are guaranteed to
+ // transfer execution to successor.
+ for (auto &I : make_range(Begin->getIterator(), End->getIterator()))
+ if (NumInstChecked++ > InlinerAttributeWindow ||
+ !isGuaranteedToTransferExecutionToSuccessor(&I))
+ return true;
+ return false;
+}
+
+static AttrBuilder IdentifyValidAttributes(CallSite CS) {
+
+ AttrBuilder AB(CS.getAttributes(), AttributeList::ReturnIndex);
+ if (AB.empty())
+ return AB;
+ AttrBuilder Valid;
+ // Only allow these white listed attributes to be propagated back to the
+ // callee. This is because other attributes may only be valid on the call
+ // itself, i.e. attributes such as signext and zeroext.
+ if (auto DerefBytes = AB.getDereferenceableBytes())
+ Valid.addDereferenceableAttr(DerefBytes);
+ if (auto DerefOrNullBytes = AB.getDereferenceableOrNullBytes())
+ Valid.addDereferenceableOrNullAttr(DerefOrNullBytes);
+ if (AB.contains(Attribute::NoAlias))
+ Valid.addAttribute(Attribute::NoAlias);
+ if (AB.contains(Attribute::NonNull))
+ Valid.addAttribute(Attribute::NonNull);
+ return Valid;
+}
+
+static void AddReturnAttributes(CallSite CS, ValueToValueMapTy &VMap) {
+ if (!UpdateReturnAttributes)
+ return;
+
+ AttrBuilder Valid = IdentifyValidAttributes(CS);
+ if (Valid.empty())
+ return;
+ auto *CalledFunction = CS.getCalledFunction();
+ auto &Context = CalledFunction->getContext();
+
+ for (auto &BB : *CalledFunction) {
+ auto *RI = dyn_cast<ReturnInst>(BB.getTerminator());
+ if (!RI || !isa<CallBase>(RI->getOperand(0)))
+ continue;
+ auto *RetVal = cast<CallBase>(RI->getOperand(0));
+ // Sanity check that the cloned RetVal exists and is a call, otherwise we
+ // cannot add the attributes on the cloned RetVal.
+ // Simplification during inlining could have transformed the cloned
+ // instruction.
+ auto *NewRetVal = dyn_cast_or_null<CallBase>(VMap.lookup(RetVal));
+ if (!NewRetVal)
+ continue;
+ // Backward propagation of attributes to the returned value may be incorrect
+ // if it is control flow dependent.
+ // Consider:
+ // @callee {
+ // %rv = call @foo()
+ // %rv2 = call @bar()
+ // if (%rv2 != null)
+ // return %rv2
+ // if (%rv == null)
+ // exit()
+ // return %rv
+ // }
+ // caller() {
+ // %val = call nonnull @callee()
+ // }
+ // Here we cannot add the nonnull attribute on either foo or bar. So, we
+ // limit the check to both RetVal and RI are in the same basic block and
+ // there are no throwing/exiting instructions between these instructions.
+ if (RI->getParent() != RetVal->getParent() ||
+ MayContainThrowingOrExitingCall(RetVal, RI))
+ continue;
+ // Add to the existing attributes of NewRetVal, i.e. the cloned call
+ // instruction.
+ // NB! When we have the same attribute already existing on NewRetVal, but
+ // with a differing value, the AttributeList's merge API honours the already
+ // existing attribute value (i.e. attributes such as dereferenceable,
+ // dereferenceable_or_null etc). See AttrBuilder::merge for more details.
+ AttributeList AL = NewRetVal->getAttributes();
+ AttributeList NewAL =
+ AL.addAttributes(Context, AttributeList::ReturnIndex, Valid);
+ NewRetVal->setAttributes(NewAL);
+ }
+}
+
/// If the inlined function has non-byval align arguments, then
/// add @llvm.assume-based alignment assumptions to preserve this information.
static void AddAlignmentAssumptions(CallSite CS, InlineFunctionInfo &IFI) {
@@ -1801,6 +1902,10 @@
// Add noalias metadata if necessary.
AddAliasScopeMetadata(CS, VMap, DL, CalleeAAR);
+ // Clone return attributes on the callsite into the calls within the inlined
+ // function which feed into its return value.
+ AddReturnAttributes(CS, VMap);
+
// Propagate llvm.mem.parallel_loop_access if necessary.
PropagateParallelLoopAccessMetadata(CS, VMap);
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