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[FunctionAttrs] Only consider provenance capture in access attr inference #138535

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Merged
merged 1 commit into from
May 6, 2025
Merged

[FunctionAttrs] Only consider provenance capture in access attr inference #138535

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9 changes: 4 additions & 5 deletions llvm/lib/Transforms/IPO/FunctionAttrs.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -908,7 +908,7 @@ determinePointerAccessAttrs(Argument *A,
for (Use &UU : CB.uses())
if (Visited.insert(&UU).second)
Worklist.push_back(&UU);
} else if (!CB.doesNotCapture(UseIndex)) {
} else if (capturesAnyProvenance(CB.getCaptureInfo(UseIndex))) {
if (!CB.onlyReadsMemory())
// If the callee can save a copy into other memory, then simply
// scanning uses of the call is insufficient. We have no way
Expand Down Expand Up @@ -1382,10 +1382,9 @@ static void addArgumentAttrs(const SCCNodeSet &SCCNodes,
}
}

// TODO(captures): Ignore address-only captures.
if (capturesAnything(CC)) {
// As the pointer may be captured, determine the pointer attributes
// looking at each argument individually.
if (capturesAnyProvenance(CC)) {
// As the pointer provenance may be captured, determine the pointer
// attributes looking at each argument individually.
for (ArgumentGraphNode *N : ArgumentSCC) {
if (DetermineAccessAttrsForSingleton(N->Definition))
Changed.insert(N->Definition->getParent());
Expand Down
4 changes: 2 additions & 2 deletions llvm/test/Transforms/FunctionAttrs/nocapture.ll
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Expand Up @@ -1234,7 +1234,7 @@ define void @dont_increase_existing_captures_scc2(ptr %p) {
define void @addr_only_scc(ptr %p) {
; FNATTRS: Function Attrs: nofree nosync nounwind memory(write, argmem: read, inaccessiblemem: none)
; FNATTRS-LABEL: define void @addr_only_scc
; FNATTRS-SAME: (ptr captures(address_is_null) [[P:%.*]]) #[[ATTR20:[0-9]+]] {
; FNATTRS-SAME: (ptr readonly captures(address_is_null) [[P:%.*]]) #[[ATTR20:[0-9]+]] {
; FNATTRS-NEXT: [[V:%.*]] = load i8, ptr [[P]], align 1
; FNATTRS-NEXT: store i8 [[V]], ptr @g, align 1
; FNATTRS-NEXT: call void @addr_only_scc2(ptr [[P]])
Expand All @@ -1257,7 +1257,7 @@ define void @addr_only_scc(ptr %p) {
define void @addr_only_scc2(ptr %p) {
; FNATTRS: Function Attrs: nofree nosync nounwind memory(write, argmem: read, inaccessiblemem: none)
; FNATTRS-LABEL: define void @addr_only_scc2
; FNATTRS-SAME: (ptr captures(address_is_null) [[P:%.*]]) #[[ATTR20]] {
; FNATTRS-SAME: (ptr readonly captures(address_is_null) [[P:%.*]]) #[[ATTR20]] {
; FNATTRS-NEXT: [[CMP:%.*]] = icmp ne ptr [[P]], null
; FNATTRS-NEXT: br i1 [[CMP]], label [[IF:%.*]], label [[EXIT:%.*]]
; FNATTRS: if:
Expand Down