[llvm] [CVP] Check whether the default case is reachable (PR #79993)
Yingwei Zheng via llvm-commits
llvm-commits at lists.llvm.org
Tue Jan 30 07:59:11 PST 2024
https://github.com/dtcxzyw updated https://github.com/llvm/llvm-project/pull/79993
>From e322d1ebb7c2e690c00d2581ab128476ed962d63 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Tue, 30 Jan 2024 20:09:37 +0800
Subject: [PATCH 1/3] [CVP] Add pre-commit tests. NFC.
---
.../CorrelatedValuePropagation/switch.ll | 295 ++++++++++++++++++
1 file changed, 295 insertions(+)
create mode 100644 llvm/test/Transforms/CorrelatedValuePropagation/switch.ll
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/switch.ll b/llvm/test/Transforms/CorrelatedValuePropagation/switch.ll
new file mode 100644
index 0000000000000..1c3c818951a63
--- /dev/null
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/switch.ll
@@ -0,0 +1,295 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt < %s -passes=correlated-propagation -S | FileCheck %s
+
+define i32 @test_unreachable_default(i32 noundef %num) {
+; CHECK-LABEL: define i32 @test_unreachable_default(
+; CHECK-SAME: i32 noundef [[NUM:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SUB:%.*]] = add i32 [[NUM]], -120
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[SUB]], 3
+; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[SUB]], i32 2
+; CHECK-NEXT: switch i32 [[COND]], label [[SW_DEFAULT:%.*]] [
+; CHECK-NEXT: i32 0, label [[SW_BB:%.*]]
+; CHECK-NEXT: i32 1, label [[SW_BB2:%.*]]
+; CHECK-NEXT: i32 2, label [[SW_BB4:%.*]]
+; CHECK-NEXT: ]
+; CHECK: sw.bb:
+; CHECK-NEXT: [[CALL:%.*]] = call i32 @call0()
+; CHECK-NEXT: br label [[CLEANUP:%.*]]
+; CHECK: sw.bb2:
+; CHECK-NEXT: [[CALL3:%.*]] = call i32 @call1()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: sw.bb4:
+; CHECK-NEXT: [[CALL5:%.*]] = call i32 @call2()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: sw.default:
+; CHECK-NEXT: [[CALL6:%.*]] = call i32 @call3()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: cleanup:
+; CHECK-NEXT: [[RETVAL_0:%.*]] = phi i32 [ [[CALL6]], [[SW_DEFAULT]] ], [ [[CALL5]], [[SW_BB4]] ], [ [[CALL3]], [[SW_BB2]] ], [ [[CALL]], [[SW_BB]] ]
+; CHECK-NEXT: ret i32 [[RETVAL_0]]
+;
+entry:
+ %sub = add i32 %num, -120
+ %cmp = icmp ult i32 %sub, 3
+ %cond = select i1 %cmp, i32 %sub, i32 2
+ switch i32 %cond, label %sw.default [
+ i32 0, label %sw.bb
+ i32 1, label %sw.bb2
+ i32 2, label %sw.bb4
+ ]
+
+sw.bb:
+ %call = call i32 @call0()
+ br label %cleanup
+
+sw.bb2:
+ %call3 = call i32 @call1()
+ br label %cleanup
+
+sw.bb4:
+ %call5 = call i32 @call2()
+ br label %cleanup
+
+sw.default:
+ %call6 = call i32 @call3()
+ br label %cleanup
+
+cleanup:
+ %retval.0 = phi i32 [ %call6, %sw.default ], [ %call5, %sw.bb4 ], [ %call3, %sw.bb2 ], [ %call, %sw.bb ]
+ ret i32 %retval.0
+}
+
+define i32 @test_unreachable_default_shared_edge(i32 noundef %num) {
+; CHECK-LABEL: define i32 @test_unreachable_default_shared_edge(
+; CHECK-SAME: i32 noundef [[NUM:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SUB:%.*]] = add i32 [[NUM]], -120
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[SUB]], 3
+; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[SUB]], i32 2
+; CHECK-NEXT: switch i32 [[COND]], label [[SW_BB4:%.*]] [
+; CHECK-NEXT: i32 0, label [[SW_BB:%.*]]
+; CHECK-NEXT: i32 1, label [[SW_BB2:%.*]]
+; CHECK-NEXT: i32 2, label [[SW_BB4]]
+; CHECK-NEXT: ]
+; CHECK: sw.bb:
+; CHECK-NEXT: [[CALL:%.*]] = call i32 @call0()
+; CHECK-NEXT: br label [[CLEANUP:%.*]]
+; CHECK: sw.bb2:
+; CHECK-NEXT: [[CALL3:%.*]] = call i32 @call1()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: sw.bb4:
+; CHECK-NEXT: [[CALL5:%.*]] = call i32 @call2()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: cleanup:
+; CHECK-NEXT: [[RETVAL_0:%.*]] = phi i32 [ [[CALL5]], [[SW_BB4]] ], [ [[CALL3]], [[SW_BB2]] ], [ [[CALL]], [[SW_BB]] ]
+; CHECK-NEXT: ret i32 [[RETVAL_0]]
+;
+entry:
+ %sub = add i32 %num, -120
+ %cmp = icmp ult i32 %sub, 3
+ %cond = select i1 %cmp, i32 %sub, i32 2
+ switch i32 %cond, label %sw.bb4 [
+ i32 0, label %sw.bb
+ i32 1, label %sw.bb2
+ i32 2, label %sw.bb4
+ ]
+
+sw.bb:
+ %call = call i32 @call0()
+ br label %cleanup
+
+sw.bb2:
+ %call3 = call i32 @call1()
+ br label %cleanup
+
+sw.bb4:
+ %call5 = call i32 @call2()
+ br label %cleanup
+
+cleanup:
+ %retval.0 = phi i32 [ %call5, %sw.bb4 ], [ %call3, %sw.bb2 ], [ %call, %sw.bb ]
+ ret i32 %retval.0
+}
+
+; Negative tests
+
+define i32 @test_reachable_default(i32 noundef %num) {
+; CHECK-LABEL: define i32 @test_reachable_default(
+; CHECK-SAME: i32 noundef [[NUM:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SUB:%.*]] = add i32 [[NUM]], -120
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[SUB]], 3
+; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[SUB]], i32 4
+; CHECK-NEXT: switch i32 [[COND]], label [[SW_DEFAULT:%.*]] [
+; CHECK-NEXT: i32 0, label [[SW_BB:%.*]]
+; CHECK-NEXT: i32 1, label [[SW_BB2:%.*]]
+; CHECK-NEXT: i32 2, label [[SW_BB4:%.*]]
+; CHECK-NEXT: ]
+; CHECK: sw.bb:
+; CHECK-NEXT: [[CALL:%.*]] = call i32 @call0()
+; CHECK-NEXT: br label [[CLEANUP:%.*]]
+; CHECK: sw.bb2:
+; CHECK-NEXT: [[CALL3:%.*]] = call i32 @call1()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: sw.bb4:
+; CHECK-NEXT: [[CALL5:%.*]] = call i32 @call2()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: sw.default:
+; CHECK-NEXT: [[CALL6:%.*]] = call i32 @call3()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: cleanup:
+; CHECK-NEXT: [[RETVAL_0:%.*]] = phi i32 [ [[CALL6]], [[SW_DEFAULT]] ], [ [[CALL5]], [[SW_BB4]] ], [ [[CALL3]], [[SW_BB2]] ], [ [[CALL]], [[SW_BB]] ]
+; CHECK-NEXT: ret i32 [[RETVAL_0]]
+;
+entry:
+ %sub = add i32 %num, -120
+ %cmp = icmp ult i32 %sub, 3
+ %cond = select i1 %cmp, i32 %sub, i32 4
+ switch i32 %cond, label %sw.default [
+ i32 0, label %sw.bb
+ i32 1, label %sw.bb2
+ i32 2, label %sw.bb4
+ ]
+
+sw.bb:
+ %call = call i32 @call0()
+ br label %cleanup
+
+sw.bb2:
+ %call3 = call i32 @call1()
+ br label %cleanup
+
+sw.bb4:
+ %call5 = call i32 @call2()
+ br label %cleanup
+
+sw.default:
+ %call6 = call i32 @call3()
+ br label %cleanup
+
+cleanup:
+ %retval.0 = phi i32 [ %call6, %sw.default ], [ %call5, %sw.bb4 ], [ %call3, %sw.bb2 ], [ %call, %sw.bb ]
+ ret i32 %retval.0
+}
+
+define i32 @test_unreachable_default_cond_may_be_undef(i32 %num) {
+; CHECK-LABEL: define i32 @test_unreachable_default_cond_may_be_undef(
+; CHECK-SAME: i32 [[NUM:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SUB:%.*]] = add i32 [[NUM]], -120
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[SUB]], 3
+; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[SUB]], i32 2
+; CHECK-NEXT: switch i32 [[COND]], label [[SW_DEFAULT:%.*]] [
+; CHECK-NEXT: i32 0, label [[SW_BB:%.*]]
+; CHECK-NEXT: i32 1, label [[SW_BB2:%.*]]
+; CHECK-NEXT: i32 2, label [[SW_BB4:%.*]]
+; CHECK-NEXT: ]
+; CHECK: sw.bb:
+; CHECK-NEXT: [[CALL:%.*]] = call i32 @call0()
+; CHECK-NEXT: br label [[CLEANUP:%.*]]
+; CHECK: sw.bb2:
+; CHECK-NEXT: [[CALL3:%.*]] = call i32 @call1()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: sw.bb4:
+; CHECK-NEXT: [[CALL5:%.*]] = call i32 @call2()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: sw.default:
+; CHECK-NEXT: [[CALL6:%.*]] = call i32 @call3()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: cleanup:
+; CHECK-NEXT: [[RETVAL_0:%.*]] = phi i32 [ [[CALL6]], [[SW_DEFAULT]] ], [ [[CALL5]], [[SW_BB4]] ], [ [[CALL3]], [[SW_BB2]] ], [ [[CALL]], [[SW_BB]] ]
+; CHECK-NEXT: ret i32 [[RETVAL_0]]
+;
+entry:
+ %sub = add i32 %num, -120
+ %cmp = icmp ult i32 %sub, 3
+ %cond = select i1 %cmp, i32 %sub, i32 2
+ switch i32 %cond, label %sw.default [
+ i32 0, label %sw.bb
+ i32 1, label %sw.bb2
+ i32 2, label %sw.bb4
+ ]
+
+sw.bb:
+ %call = call i32 @call0()
+ br label %cleanup
+
+sw.bb2:
+ %call3 = call i32 @call1()
+ br label %cleanup
+
+sw.bb4:
+ %call5 = call i32 @call2()
+ br label %cleanup
+
+sw.default:
+ %call6 = call i32 @call3()
+ br label %cleanup
+
+cleanup:
+ %retval.0 = phi i32 [ %call6, %sw.default ], [ %call5, %sw.bb4 ], [ %call3, %sw.bb2 ], [ %call, %sw.bb ]
+ ret i32 %retval.0
+}
+
+define i32 @test_default_is_already_unreachable(i32 %num) {
+; CHECK-LABEL: define i32 @test_default_is_already_unreachable(
+; CHECK-SAME: i32 [[NUM:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SUB:%.*]] = add i32 [[NUM]], -120
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[SUB]], 3
+; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[SUB]], i32 2
+; CHECK-NEXT: switch i32 [[COND]], label [[SW_DEFAULT:%.*]] [
+; CHECK-NEXT: i32 0, label [[SW_BB:%.*]]
+; CHECK-NEXT: i32 1, label [[SW_BB2:%.*]]
+; CHECK-NEXT: i32 2, label [[SW_BB4:%.*]]
+; CHECK-NEXT: ]
+; CHECK: sw.bb:
+; CHECK-NEXT: [[CALL:%.*]] = call i32 @call0()
+; CHECK-NEXT: br label [[CLEANUP:%.*]]
+; CHECK: sw.bb2:
+; CHECK-NEXT: [[CALL3:%.*]] = call i32 @call1()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: sw.bb4:
+; CHECK-NEXT: [[CALL5:%.*]] = call i32 @call2()
+; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: sw.default:
+; CHECK-NEXT: unreachable
+; CHECK: cleanup:
+; CHECK-NEXT: [[RETVAL_0:%.*]] = phi i32 [ [[CALL5]], [[SW_BB4]] ], [ [[CALL3]], [[SW_BB2]] ], [ [[CALL]], [[SW_BB]] ]
+; CHECK-NEXT: ret i32 [[RETVAL_0]]
+;
+entry:
+ %sub = add i32 %num, -120
+ %cmp = icmp ult i32 %sub, 3
+ %cond = select i1 %cmp, i32 %sub, i32 2
+ switch i32 %cond, label %sw.default [
+ i32 0, label %sw.bb
+ i32 1, label %sw.bb2
+ i32 2, label %sw.bb4
+ ]
+
+sw.bb:
+ %call = call i32 @call0()
+ br label %cleanup
+
+sw.bb2:
+ %call3 = call i32 @call1()
+ br label %cleanup
+
+sw.bb4:
+ %call5 = call i32 @call2()
+ br label %cleanup
+
+sw.default:
+ unreachable
+
+cleanup:
+ %retval.0 = phi i32 [ %call5, %sw.bb4 ], [ %call3, %sw.bb2 ], [ %call, %sw.bb ]
+ ret i32 %retval.0
+}
+
+declare i32 @call0()
+declare i32 @call1()
+declare i32 @call2()
+declare i32 @call3()
>From 1636de95d142b0fdffb7e3b73ba3c3722695badf Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Tue, 30 Jan 2024 20:10:54 +0800
Subject: [PATCH 2/3] [CVP] Check whether the default case is reachable
---
.../Scalar/CorrelatedValuePropagation.cpp | 31 +++++++++++++++++++
.../CorrelatedValuePropagation/basic.ll | 11 ++++---
.../CorrelatedValuePropagation/switch.ll | 12 ++++---
3 files changed, 45 insertions(+), 9 deletions(-)
diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
index 9235850de92f3..e1a5d83e4b96c 100644
--- a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -371,6 +371,7 @@ static bool processSwitch(SwitchInst *I, LazyValueInfo *LVI,
{ // Scope for SwitchInstProfUpdateWrapper. It must not live during
// ConstantFoldTerminator() as the underlying SwitchInst can be changed.
SwitchInstProfUpdateWrapper SI(*I);
+ unsigned ReachableCaseCount = 0;
for (auto CI = SI->case_begin(), CE = SI->case_end(); CI != CE;) {
ConstantInt *Case = CI->getCaseValue();
@@ -407,6 +408,35 @@ static bool processSwitch(SwitchInst *I, LazyValueInfo *LVI,
// Increment the case iterator since we didn't delete it.
++CI;
+ ++ReachableCaseCount;
+ }
+
+ BasicBlock *DefaultDest = SI->getDefaultDest();
+ if (!isa<UnreachableInst>(DefaultDest->getFirstNonPHIOrDbg())) {
+ ConstantRange CR = LVI->getConstantRangeAtUse(I->getOperandUse(0),
+ /*UndefAllowed*/ false);
+ // The default dest is unreachable if all cases are covered.
+ if (!CR.isSizeLargerThan(ReachableCaseCount)) {
+ BasicBlock *NewUnreachableBB =
+ BasicBlock::Create(BB->getContext(), "default.unreachable",
+ BB->getParent(), DefaultDest);
+ new UnreachableInst(BB->getContext(), NewUnreachableBB);
+
+ bool RemoveOldBB = --SuccessorsCount[DefaultDest] == 0;
+
+ if (RemoveOldBB)
+ DefaultDest->removePredecessor(BB);
+ SI->setDefaultDest(NewUnreachableBB);
+
+ if (RemoveOldBB)
+ DTU.applyUpdatesPermissive(
+ {{DominatorTree::Delete, BB, DefaultDest}});
+ DTU.applyUpdatesPermissive(
+ {{DominatorTree::Insert, BB, NewUnreachableBB}});
+
+ ++NumDeadCases;
+ Changed = true;
+ }
}
}
@@ -1227,6 +1257,7 @@ CorrelatedValuePropagationPass::run(Function &F, FunctionAnalysisManager &AM) {
if (!Changed) {
PA = PreservedAnalyses::all();
} else {
+ assert(DT->verify());
PA.preserve<DominatorTreeAnalysis>();
PA.preserve<LazyValueAnalysis>();
}
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/basic.ll b/llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
index 6227a5c822b10..9941d4c070d39 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
@@ -442,7 +442,7 @@ define i32 @switch_range(i32 %cond) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[S:%.*]] = urem i32 [[COND:%.*]], 3
; CHECK-NEXT: [[S1:%.*]] = add nuw nsw i32 [[S]], 1
-; CHECK-NEXT: switch i32 [[S1]], label [[UNREACHABLE:%.*]] [
+; CHECK-NEXT: switch i32 [[S1]], label [[DEFAULT_UNREACHABLE:%.*]] [
; CHECK-NEXT: i32 1, label [[EXIT1:%.*]]
; CHECK-NEXT: i32 2, label [[EXIT2:%.*]]
; CHECK-NEXT: i32 3, label [[EXIT1]]
@@ -451,6 +451,8 @@ define i32 @switch_range(i32 %cond) {
; CHECK-NEXT: ret i32 1
; CHECK: exit2:
; CHECK-NEXT: ret i32 2
+; CHECK: default.unreachable:
+; CHECK-NEXT: unreachable
; CHECK: unreachable:
; CHECK-NEXT: ret i32 0
;
@@ -513,10 +515,9 @@ define i8 @switch_defaultdest_multipleuse(i8 %t0) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[O:%.*]] = or i8 [[T0:%.*]], 1
; CHECK-NEXT: [[R:%.*]] = srem i8 1, [[O]]
-; CHECK-NEXT: switch i8 [[R]], label [[EXIT:%.*]] [
-; CHECK-NEXT: i8 0, label [[EXIT]]
-; CHECK-NEXT: i8 1, label [[EXIT]]
-; CHECK-NEXT: ]
+; CHECK-NEXT: br label [[EXIT:%.*]]
+; CHECK: default.unreachable:
+; CHECK-NEXT: unreachable
; CHECK: exit:
; CHECK-NEXT: ret i8 0
;
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/switch.ll b/llvm/test/Transforms/CorrelatedValuePropagation/switch.ll
index 1c3c818951a63..4d396b5422401 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/switch.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/switch.ll
@@ -8,7 +8,7 @@ define i32 @test_unreachable_default(i32 noundef %num) {
; CHECK-NEXT: [[SUB:%.*]] = add i32 [[NUM]], -120
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[SUB]], 3
; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[SUB]], i32 2
-; CHECK-NEXT: switch i32 [[COND]], label [[SW_DEFAULT:%.*]] [
+; CHECK-NEXT: switch i32 [[COND]], label [[DEFAULT_UNREACHABLE:%.*]] [
; CHECK-NEXT: i32 0, label [[SW_BB:%.*]]
; CHECK-NEXT: i32 1, label [[SW_BB2:%.*]]
; CHECK-NEXT: i32 2, label [[SW_BB4:%.*]]
@@ -22,11 +22,13 @@ define i32 @test_unreachable_default(i32 noundef %num) {
; CHECK: sw.bb4:
; CHECK-NEXT: [[CALL5:%.*]] = call i32 @call2()
; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: default.unreachable:
+; CHECK-NEXT: unreachable
; CHECK: sw.default:
; CHECK-NEXT: [[CALL6:%.*]] = call i32 @call3()
; CHECK-NEXT: br label [[CLEANUP]]
; CHECK: cleanup:
-; CHECK-NEXT: [[RETVAL_0:%.*]] = phi i32 [ [[CALL6]], [[SW_DEFAULT]] ], [ [[CALL5]], [[SW_BB4]] ], [ [[CALL3]], [[SW_BB2]] ], [ [[CALL]], [[SW_BB]] ]
+; CHECK-NEXT: [[RETVAL_0:%.*]] = phi i32 [ [[CALL6]], [[SW_DEFAULT:%.*]] ], [ [[CALL5]], [[SW_BB4]] ], [ [[CALL3]], [[SW_BB2]] ], [ [[CALL]], [[SW_BB]] ]
; CHECK-NEXT: ret i32 [[RETVAL_0]]
;
entry:
@@ -67,10 +69,10 @@ define i32 @test_unreachable_default_shared_edge(i32 noundef %num) {
; CHECK-NEXT: [[SUB:%.*]] = add i32 [[NUM]], -120
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[SUB]], 3
; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[SUB]], i32 2
-; CHECK-NEXT: switch i32 [[COND]], label [[SW_BB4:%.*]] [
+; CHECK-NEXT: switch i32 [[COND]], label [[DEFAULT_UNREACHABLE:%.*]] [
; CHECK-NEXT: i32 0, label [[SW_BB:%.*]]
; CHECK-NEXT: i32 1, label [[SW_BB2:%.*]]
-; CHECK-NEXT: i32 2, label [[SW_BB4]]
+; CHECK-NEXT: i32 2, label [[SW_BB4:%.*]]
; CHECK-NEXT: ]
; CHECK: sw.bb:
; CHECK-NEXT: [[CALL:%.*]] = call i32 @call0()
@@ -78,6 +80,8 @@ define i32 @test_unreachable_default_shared_edge(i32 noundef %num) {
; CHECK: sw.bb2:
; CHECK-NEXT: [[CALL3:%.*]] = call i32 @call1()
; CHECK-NEXT: br label [[CLEANUP]]
+; CHECK: default.unreachable:
+; CHECK-NEXT: unreachable
; CHECK: sw.bb4:
; CHECK-NEXT: [[CALL5:%.*]] = call i32 @call2()
; CHECK-NEXT: br label [[CLEANUP]]
>From f6fedc97acd6d0c1226e9717dfdf0335dae733b8 Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Tue, 30 Jan 2024 23:56:32 +0800
Subject: [PATCH 3/3] fixup! [CVP] Check whether the default case is reachable
---
.../Scalar/CorrelatedValuePropagation.cpp | 21 ++++++++++---------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
index e1a5d83e4b96c..0a3ddcbeaa16e 100644
--- a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -412,7 +412,8 @@ static bool processSwitch(SwitchInst *I, LazyValueInfo *LVI,
}
BasicBlock *DefaultDest = SI->getDefaultDest();
- if (!isa<UnreachableInst>(DefaultDest->getFirstNonPHIOrDbg())) {
+ if (ReachableCaseCount > 1 &&
+ !isa<UnreachableInst>(DefaultDest->getFirstNonPHIOrDbg())) {
ConstantRange CR = LVI->getConstantRangeAtUse(I->getOperandUse(0),
/*UndefAllowed*/ false);
// The default dest is unreachable if all cases are covered.
@@ -422,17 +423,12 @@ static bool processSwitch(SwitchInst *I, LazyValueInfo *LVI,
BB->getParent(), DefaultDest);
new UnreachableInst(BB->getContext(), NewUnreachableBB);
- bool RemoveOldBB = --SuccessorsCount[DefaultDest] == 0;
-
- if (RemoveOldBB)
- DefaultDest->removePredecessor(BB);
+ DefaultDest->removePredecessor(BB);
SI->setDefaultDest(NewUnreachableBB);
- if (RemoveOldBB)
- DTU.applyUpdatesPermissive(
- {{DominatorTree::Delete, BB, DefaultDest}});
DTU.applyUpdatesPermissive(
- {{DominatorTree::Insert, BB, NewUnreachableBB}});
+ {{DominatorTree::Delete, BB, DefaultDest},
+ {DominatorTree::Insert, BB, NewUnreachableBB}});
++NumDeadCases;
Changed = true;
@@ -1257,7 +1253,12 @@ CorrelatedValuePropagationPass::run(Function &F, FunctionAnalysisManager &AM) {
if (!Changed) {
PA = PreservedAnalyses::all();
} else {
- assert(DT->verify());
+#if defined(EXPENSIVE_CHECKS)
+ assert(DT->verify(DominatorTree::VerificationLevel::Full));
+#else
+ assert(DT->verify(DominatorTree::VerificationLevel::Fast));
+#endif // EXPENSIVE_CHECKS
+
PA.preserve<DominatorTreeAnalysis>();
PA.preserve<LazyValueAnalysis>();
}
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