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[InstCombinePHI] Remove dead PHI on UnaryOperator #71386

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Merged
merged 1 commit into from
Nov 7, 2023
Merged

[InstCombinePHI] Remove dead PHI on UnaryOperator #71386

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3 changes: 2 additions & 1 deletion llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1440,7 +1440,8 @@ Instruction *InstCombinerImpl::visitPHINode(PHINode &PN) {
// are induction variable analysis (sometimes) and ADCE, which is only run
// late.
if (PHIUser->hasOneUse() &&
(isa<BinaryOperator>(PHIUser) || isa<GetElementPtrInst>(PHIUser)) &&
(isa<BinaryOperator>(PHIUser) || isa<UnaryOperator>(PHIUser) ||
isa<GetElementPtrInst>(PHIUser)) &&
PHIUser->user_back() == &PN) {
return replaceInstUsesWith(PN, PoisonValue::get(PN.getType()));
}
Expand Down
47 changes: 34 additions & 13 deletions llvm/test/Transforms/InstCombine/phi.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -154,6 +154,27 @@ Exit: ; preds = %Loop
ret i32 0
}

define i32 @test_dead_UnaryOp_cycle(double %A, i1 %cond) {
; CHECK-LABEL: @test_dead_UnaryOp_cycle(
; CHECK-NEXT: BB0:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: Loop:
; CHECK-NEXT: br i1 [[COND:%.*]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK: Exit:
; CHECK-NEXT: ret i32 0
;
BB0:
br label %Loop

Loop: ; preds = %Loop, %BB0
%B = phi double [ %A, %BB0 ], [ %C, %Loop ]
%C = fneg double %B
br i1 %cond, label %Loop, label %Exit

Exit: ; preds = %Loop
ret i32 0
}

define i32 @test_dead_cycle_two_insts(i32 %A, i1 %cond) {
; CHECK-LABEL: @test_dead_cycle_two_insts(
; CHECK-NEXT: BB0:
Expand Down Expand Up @@ -901,14 +922,14 @@ define i1 @test26(i32 %n) {
; CHECK: one:
; CHECK-NEXT: [[C:%.*]] = call i1 @test26a()
; CHECK-NEXT: switch i32 [[N:%.*]], label [[END:%.*]] [
; CHECK-NEXT: i32 2, label [[TWO:%.*]]
; CHECK-NEXT: i32 3, label [[THREE:%.*]]
; CHECK-NEXT: i32 2, label [[TWO:%.*]]
; CHECK-NEXT: i32 3, label [[THREE:%.*]]
; CHECK-NEXT: ]
; CHECK: two:
; CHECK-NEXT: [[D:%.*]] = call i1 @test26a()
; CHECK-NEXT: switch i32 [[N]], label [[END]] [
; CHECK-NEXT: i32 10, label [[ONE]]
; CHECK-NEXT: i32 30, label [[THREE]]
; CHECK-NEXT: i32 10, label [[ONE]]
; CHECK-NEXT: i32 30, label [[THREE]]
; CHECK-NEXT: ]
; CHECK: three:
; CHECK-NEXT: [[E:%.*]] = call i1 @test26a()
Expand Down Expand Up @@ -977,8 +998,8 @@ define i1 @PR24766(i8 %x1, i8 %x2, i8 %condition) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CONV:%.*]] = sext i8 [[CONDITION:%.*]] to i32
; CHECK-NEXT: switch i32 [[CONV]], label [[EPILOG:%.*]] [
; CHECK-NEXT: i32 0, label [[SW1:%.*]]
; CHECK-NEXT: i32 1, label [[SW2:%.*]]
; CHECK-NEXT: i32 0, label [[SW1:%.*]]
; CHECK-NEXT: i32 1, label [[SW2:%.*]]
; CHECK-NEXT: ]
; CHECK: sw1:
; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i8 [[X1:%.*]], [[X2:%.*]]
Expand Down Expand Up @@ -1021,8 +1042,8 @@ define i1 @PR24766_no_constants(i8 %x1, i8 %x2, i8 %condition, i1 %another_condi
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CONV:%.*]] = sext i8 [[CONDITION:%.*]] to i32
; CHECK-NEXT: switch i32 [[CONV]], label [[EPILOG:%.*]] [
; CHECK-NEXT: i32 0, label [[SW1:%.*]]
; CHECK-NEXT: i32 1, label [[SW2:%.*]]
; CHECK-NEXT: i32 0, label [[SW1:%.*]]
; CHECK-NEXT: i32 1, label [[SW2:%.*]]
; CHECK-NEXT: ]
; CHECK: sw1:
; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i8 [[X1:%.*]], [[X2:%.*]]
Expand Down Expand Up @@ -1066,8 +1087,8 @@ define i1 @PR24766_two_constants(i8 %x1, i8 %x2, i8 %condition) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CONV:%.*]] = sext i8 [[CONDITION:%.*]] to i32
; CHECK-NEXT: switch i32 [[CONV]], label [[EPILOG:%.*]] [
; CHECK-NEXT: i32 0, label [[SW1:%.*]]
; CHECK-NEXT: i32 1, label [[SW2:%.*]]
; CHECK-NEXT: i32 0, label [[SW1:%.*]]
; CHECK-NEXT: i32 1, label [[SW2:%.*]]
; CHECK-NEXT: ]
; CHECK: sw1:
; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i8 [[X1:%.*]], [[X2:%.*]]
Expand Down Expand Up @@ -1109,9 +1130,9 @@ define i1 @PR24766_two_constants_two_var(i8 %x1, i8 %x2, i8 %condition) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CONV:%.*]] = sext i8 [[CONDITION:%.*]] to i32
; CHECK-NEXT: switch i32 [[CONV]], label [[EPILOG:%.*]] [
; CHECK-NEXT: i32 0, label [[SW1:%.*]]
; CHECK-NEXT: i32 1, label [[SW2:%.*]]
; CHECK-NEXT: i32 2, label [[SW3:%.*]]
; CHECK-NEXT: i32 0, label [[SW1:%.*]]
; CHECK-NEXT: i32 1, label [[SW2:%.*]]
; CHECK-NEXT: i32 2, label [[SW3:%.*]]
; CHECK-NEXT: ]
; CHECK: sw1:
; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i8 [[X1:%.*]], [[X2:%.*]]
Expand Down