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AtomicExpand: Stop trying to prune cmpxchg extractvalue users #103211

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AtomicExpand: Stop trying to prune cmpxchg extractvalue users #103211

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7 changes: 0 additions & 7 deletions llvm/lib/CodeGen/AtomicExpandPass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1514,7 +1514,6 @@ bool AtomicExpandImpl::expandAtomicCmpXchg(AtomicCmpXchgInst *CI) {

// Look for any users of the cmpxchg that are just comparing the loaded value
// against the desired one, and replace them with the CFG-derived version.
SmallVector<ExtractValueInst *, 2> PrunedInsts;
for (auto *User : CI->users()) {
ExtractValueInst *EV = dyn_cast<ExtractValueInst>(User);
if (!EV)
Expand All @@ -1527,14 +1526,8 @@ bool AtomicExpandImpl::expandAtomicCmpXchg(AtomicCmpXchgInst *CI) {
EV->replaceAllUsesWith(Loaded);
else
EV->replaceAllUsesWith(Success);

PrunedInsts.push_back(EV);
}

// We can remove the instructions now we're no longer iterating through them.
for (auto *EV : PrunedInsts)
EV->eraseFromParent();

if (!CI->use_empty()) {
// Some use of the full struct return that we don't understand has happened,
// so we've got to reconstruct it properly.
Expand Down
12 changes: 12 additions & 0 deletions llvm/test/Transforms/AtomicExpand/ARM/cmpxchg-weak.ll
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Expand Up @@ -34,6 +34,9 @@ define i32 @test_cmpxchg_seq_cst(ptr %addr, i32 %desired, i32 %new) {
; CHECK: [[CMPXCHG_END]]:
; CHECK-NEXT: [[LOADED_EXIT:%.*]] = phi i32 [ [[LOADED_TRYSTORE]], %[[CMPXCHG_SUCCESS]] ], [ [[LOADED_FAILURE]], %[[CMPXCHG_FAILURE]] ]
; CHECK-NEXT: [[SUCCESS1:%.*]] = phi i1 [ true, %[[CMPXCHG_SUCCESS]] ], [ false, %[[CMPXCHG_FAILURE]] ]
; CHECK-NEXT: [[TMP3:%.*]] = insertvalue { i32, i1 } poison, i32 [[LOADED_EXIT]], 0
; CHECK-NEXT: [[TMP4:%.*]] = insertvalue { i32, i1 } [[TMP3]], i1 [[SUCCESS1]], 1
; CHECK-NEXT: [[OLDVAL:%.*]] = extractvalue { i32, i1 } [[TMP4]], 0
; CHECK-NEXT: ret i32 [[LOADED_EXIT]]
;
%pair = cmpxchg weak ptr %addr, i32 %desired, i32 %new seq_cst seq_cst
Expand Down Expand Up @@ -72,6 +75,9 @@ define i1 @test_cmpxchg_weak_fail(ptr %addr, i32 %desired, i32 %new) {
; CHECK: [[CMPXCHG_END]]:
; CHECK-NEXT: [[LOADED_EXIT:%.*]] = phi i32 [ [[LOADED_TRYSTORE]], %[[CMPXCHG_SUCCESS]] ], [ [[LOADED_FAILURE]], %[[CMPXCHG_FAILURE]] ]
; CHECK-NEXT: [[SUCCESS1:%.*]] = phi i1 [ true, %[[CMPXCHG_SUCCESS]] ], [ false, %[[CMPXCHG_FAILURE]] ]
; CHECK-NEXT: [[TMP3:%.*]] = insertvalue { i32, i1 } poison, i32 [[LOADED_EXIT]], 0
; CHECK-NEXT: [[TMP4:%.*]] = insertvalue { i32, i1 } [[TMP3]], i1 [[SUCCESS1]], 1
; CHECK-NEXT: [[OLDVAL:%.*]] = extractvalue { i32, i1 } [[TMP4]], 1
; CHECK-NEXT: ret i1 [[SUCCESS1]]
;
%pair = cmpxchg weak ptr %addr, i32 %desired, i32 %new seq_cst monotonic
Expand Down Expand Up @@ -108,6 +114,9 @@ define i32 @test_cmpxchg_monotonic(ptr %addr, i32 %desired, i32 %new) {
; CHECK: [[CMPXCHG_END]]:
; CHECK-NEXT: [[LOADED_EXIT:%.*]] = phi i32 [ [[LOADED_TRYSTORE]], %[[CMPXCHG_SUCCESS]] ], [ [[LOADED_FAILURE]], %[[CMPXCHG_FAILURE]] ]
; CHECK-NEXT: [[SUCCESS1:%.*]] = phi i1 [ true, %[[CMPXCHG_SUCCESS]] ], [ false, %[[CMPXCHG_FAILURE]] ]
; CHECK-NEXT: [[TMP3:%.*]] = insertvalue { i32, i1 } poison, i32 [[LOADED_EXIT]], 0
; CHECK-NEXT: [[TMP4:%.*]] = insertvalue { i32, i1 } [[TMP3]], i1 [[SUCCESS1]], 1
; CHECK-NEXT: [[OLDVAL:%.*]] = extractvalue { i32, i1 } [[TMP4]], 0
; CHECK-NEXT: ret i32 [[LOADED_EXIT]]
;
%pair = cmpxchg weak ptr %addr, i32 %desired, i32 %new monotonic monotonic
Expand Down Expand Up @@ -147,6 +156,9 @@ define i32 @test_cmpxchg_seq_cst_minsize(ptr %addr, i32 %desired, i32 %new) mins
; CHECK: [[CMPXCHG_END]]:
; CHECK-NEXT: [[LOADED_EXIT:%.*]] = phi i32 [ [[LOADED_TRYSTORE]], %[[CMPXCHG_SUCCESS]] ], [ [[LOADED_FAILURE]], %[[CMPXCHG_FAILURE]] ]
; CHECK-NEXT: [[SUCCESS1:%.*]] = phi i1 [ true, %[[CMPXCHG_SUCCESS]] ], [ false, %[[CMPXCHG_FAILURE]] ]
; CHECK-NEXT: [[TMP3:%.*]] = insertvalue { i32, i1 } poison, i32 [[LOADED_EXIT]], 0
; CHECK-NEXT: [[TMP4:%.*]] = insertvalue { i32, i1 } [[TMP3]], i1 [[SUCCESS1]], 1
; CHECK-NEXT: [[OLDVAL:%.*]] = extractvalue { i32, i1 } [[TMP4]], 0
; CHECK-NEXT: ret i32 [[LOADED_EXIT]]
;
%pair = cmpxchg weak ptr %addr, i32 %desired, i32 %new seq_cst seq_cst
Expand Down
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