[FunctionAttrs] Only consider provenance capture in access attr inference #138535
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…ence For the purpose of infering readonly/writeonly/readnone on the arguments, we only care about provenance captures, not address captures.
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@llvm/pr-subscribers-llvm-transforms Author: Nikita Popov (nikic) ChangesFor the purpose of inferring readonly/writeonly/readnone on arguments, we only care about provenance captures, not address captures. Full diff: https://github.com/llvm/llvm-project/pull/138535.diff 2 Files Affected:
diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index 74e8a849803d2..f918d7e059b63 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -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
@@ -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());
diff --git a/llvm/test/Transforms/FunctionAttrs/nocapture.ll b/llvm/test/Transforms/FunctionAttrs/nocapture.ll
index a5afa0ed365fb..9d6acc410de75 100644
--- a/llvm/test/Transforms/FunctionAttrs/nocapture.ll
+++ b/llvm/test/Transforms/FunctionAttrs/nocapture.ll
@@ -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]])
@@ -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:
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GeorgeARM
pushed a commit
to GeorgeARM/llvm-project
that referenced
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May 7, 2025
…ence (llvm#138535) For the purpose of inferring readonly/writeonly/readnone on arguments, we only care about provenance captures, not address captures.
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For the purpose of inferring readonly/writeonly/readnone on arguments, we only care about provenance captures, not address captures.