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[ConstraintElim] Support adding facts from switch terminators. #67061

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merged 1 commit into from
Sep 22, 2023
Merged

[ConstraintElim] Support adding facts from switch terminators. #67061

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12 changes: 12 additions & 0 deletions llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -831,6 +831,18 @@ void State::addInfoFor(BasicBlock &BB) {
GuaranteedToExecute &= isGuaranteedToTransferExecutionToSuccessor(&I);
}

if (auto *Switch = dyn_cast<SwitchInst>(BB.getTerminator())) {
for (auto &Case : Switch->cases()) {
BasicBlock *Succ = Case.getCaseSuccessor();
Value *V = Case.getCaseValue();
if (!canAddSuccessor(BB, Succ))
continue;
WorkList.emplace_back(FactOrCheck::getConditionFact(
DT.getNode(Succ), CmpInst::ICMP_EQ, Switch->getCondition(), V));
}
return;
}

auto *Br = dyn_cast<BranchInst>(BB.getTerminator());
if (!Br || !Br->isConditional())
return;
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12 changes: 3 additions & 9 deletions llvm/test/Transforms/ConstraintElimination/switch.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -57,14 +57,10 @@ define i1 @simplify_based_on_switch(i8 %x) {
; CHECK-NEXT: [[RES_1:%.*]] = xor i1 [[C_1]], [[C_2]]
; CHECK-NEXT: ret i1 [[RES_1]]
; CHECK: exit.2:
; CHECK-NEXT: [[T_1:%.*]] = icmp ult i8 [[X]], 7
; CHECK-NEXT: [[F_1:%.*]] = icmp ult i8 [[X]], 6
; CHECK-NEXT: [[RES_2:%.*]] = xor i1 [[T_1]], [[F_1]]
; CHECK-NEXT: [[RES_2:%.*]] = xor i1 true, false
; CHECK-NEXT: ret i1 [[RES_2]]
; CHECK: exit.3:
; CHECK-NEXT: [[T_2:%.*]] = icmp ult i8 [[X]], 11
; CHECK-NEXT: [[F_2:%.*]] = icmp ult i8 [[X]], 10
; CHECK-NEXT: [[RES_3:%.*]] = xor i1 [[T_2]], [[F_2]]
; CHECK-NEXT: [[RES_3:%.*]] = xor i1 true, false
; CHECK-NEXT: ret i1 [[RES_3]]
;
entry:
Expand Down Expand Up @@ -105,9 +101,7 @@ define i1 @simplify_based_on_switch_successor_branches(i8 %x) {
; CHECK-NEXT: [[RES_1:%.*]] = xor i1 [[C_1]], [[C_2]]
; CHECK-NEXT: ret i1 [[RES_1]]
; CHECK: exit.2:
; CHECK-NEXT: [[T_1:%.*]] = icmp ult i8 [[X]], 7
; CHECK-NEXT: [[F_1:%.*]] = icmp ult i8 [[X]], 6
; CHECK-NEXT: [[RES_2:%.*]] = xor i1 [[T_1]], [[F_1]]
; CHECK-NEXT: [[RES_2:%.*]] = xor i1 true, false
; CHECK-NEXT: call void @use(i1 [[RES_2]])
; CHECK-NEXT: br label [[EXIT_3]]
; CHECK: exit.3:
Expand Down