[llvm] [DFAJumpThreading] Unify equivalent states (PR #162447)
Hongyu Chen via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 8 02:36:46 PDT 2025
https://github.com/XChy created https://github.com/llvm/llvm-project/pull/162447
DFAJumpThreading determines the switch destination of a threadable path based on its next state and cannot reuse cloned blocks if their destinations differ.
However, different states may lead to the same destination. This patch unifies equivalent states, thereby avoiding redundant duplication of cloned blocks.
>From f6eb2f8cb4d75f1c1fa5bfa22b072ca3b93e8466 Mon Sep 17 00:00:00 2001
From: XChy <xxs_chy at outlook.com>
Date: Wed, 8 Oct 2025 17:12:33 +0800
Subject: [PATCH 1/2] Precommit testcases
---
.../DFAJumpThreading/equivalent-states.ll | 317 ++++++++++++++++++
1 file changed, 317 insertions(+)
create mode 100644 llvm/test/Transforms/DFAJumpThreading/equivalent-states.ll
diff --git a/llvm/test/Transforms/DFAJumpThreading/equivalent-states.ll b/llvm/test/Transforms/DFAJumpThreading/equivalent-states.ll
new file mode 100644
index 0000000000000..36c07a7fa478f
--- /dev/null
+++ b/llvm/test/Transforms/DFAJumpThreading/equivalent-states.ll
@@ -0,0 +1,317 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3
+; RUN: opt -S -passes=dfa-jump-threading %s | FileCheck %s
+
+declare void @do_something()
+declare void @user(i32)
+
+define void @equivalent_on_default(i1 %c1) {
+; CHECK-LABEL: define void @equivalent_on_default(
+; CHECK-SAME: i1 [[C1:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[SWITCH_BB:%.*]]
+; CHECK: switch_bb:
+; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ poison, [[CASE2END:%.*]] ]
+; CHECK-NEXT: switch i32 [[PHI]], label [[DEFAULT_DEST:%.*]] [
+; CHECK-NEXT: i32 0, label [[CASE1:%.*]]
+; CHECK-NEXT: i32 1, label [[CASE2:%.*]]
+; CHECK-NEXT: ]
+; CHECK: switch_bb.jt3:
+; CHECK-NEXT: [[PHI_JT3:%.*]] = phi i32 [ [[PHI_CASE2_JT3:%.*]], [[CASE2END_JT3:%.*]] ]
+; CHECK-NEXT: br label [[DEFAULT_DEST]]
+; CHECK: switch_bb.jt2:
+; CHECK-NEXT: [[PHI_JT2:%.*]] = phi i32 [ [[PHI_CASE2_JT2:%.*]], [[CASE2END_JT2:%.*]] ]
+; CHECK-NEXT: br label [[DEFAULT_DEST]]
+; CHECK: switch_bb.jt1:
+; CHECK-NEXT: [[PHI_JT1:%.*]] = phi i32 [ 1, [[CASE1]] ]
+; CHECK-NEXT: br label [[CASE2]]
+; CHECK: case1:
+; CHECK-NEXT: br label [[SWITCH_BB_JT1:%.*]]
+; CHECK: case2:
+; CHECK-NEXT: br i1 [[C1]], label [[CASE2THEN:%.*]], label [[CASE2END_JT2]]
+; CHECK: case2then:
+; CHECK-NEXT: br label [[CASE2END_JT3]]
+; CHECK: case2end:
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB]]
+; CHECK: case2end.jt3:
+; CHECK-NEXT: [[PHI_CASE2_JT3]] = phi i32 [ 3, [[CASE2THEN]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT3:%.*]]
+; CHECK: case2end.jt2:
+; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT2:%.*]]
+; CHECK: default_dest:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %switch_bb
+
+switch_bb:
+ %phi = phi i32 [ 0, %entry ], [ 1, %case1 ], [ %phi_case2, %case2end ]
+ switch i32 %phi, label %default_dest [
+ i32 0, label %case1
+ i32 1, label %case2
+ ]
+
+case1:
+ br label %switch_bb
+
+case2:
+ br i1 %c1, label %case2then, label %case2end
+
+case2then:
+ br label %case2end
+
+case2end:
+ %phi_case2 = phi i32 [ 2, %case2 ] , [ 3, %case2then ]
+ call void @do_something()
+ br label %switch_bb
+
+default_dest:
+ ret void
+}
+
+define void @equivalent_on_default_user(i1 %c1) {
+; CHECK-LABEL: define void @equivalent_on_default_user(
+; CHECK-SAME: i1 [[C1:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[SWITCH_BB:%.*]]
+; CHECK: switch_bb:
+; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ poison, [[CASE2END:%.*]] ]
+; CHECK-NEXT: switch i32 [[PHI]], label [[DEFAULT_DEST:%.*]] [
+; CHECK-NEXT: i32 0, label [[CASE1:%.*]]
+; CHECK-NEXT: i32 1, label [[CASE2:%.*]]
+; CHECK-NEXT: ]
+; CHECK: switch_bb.jt3:
+; CHECK-NEXT: [[PHI_JT3:%.*]] = phi i32 [ [[PHI_CASE2_JT3:%.*]], [[CASE2END_JT3:%.*]] ]
+; CHECK-NEXT: br label [[DEFAULT_DEST]]
+; CHECK: switch_bb.jt2:
+; CHECK-NEXT: [[PHI_JT2:%.*]] = phi i32 [ [[PHI_CASE2_JT2:%.*]], [[CASE2END_JT2:%.*]] ]
+; CHECK-NEXT: br label [[DEFAULT_DEST]]
+; CHECK: switch_bb.jt1:
+; CHECK-NEXT: [[PHI_JT1:%.*]] = phi i32 [ 1, [[CASE1]] ]
+; CHECK-NEXT: br label [[CASE2]]
+; CHECK: case1:
+; CHECK-NEXT: br label [[SWITCH_BB_JT1:%.*]]
+; CHECK: case2:
+; CHECK-NEXT: br i1 [[C1]], label [[CASE2THEN:%.*]], label [[CASE2END_JT2]]
+; CHECK: case2then:
+; CHECK-NEXT: br label [[CASE2END_JT3]]
+; CHECK: case2end:
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: call void @user(i32 poison)
+; CHECK-NEXT: br label [[SWITCH_BB]]
+; CHECK: case2end.jt3:
+; CHECK-NEXT: [[PHI_CASE2_JT3]] = phi i32 [ 3, [[CASE2THEN]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: call void @user(i32 [[PHI_CASE2_JT3]])
+; CHECK-NEXT: br label [[SWITCH_BB_JT3:%.*]]
+; CHECK: case2end.jt2:
+; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: call void @user(i32 [[PHI_CASE2_JT2]])
+; CHECK-NEXT: br label [[SWITCH_BB_JT2:%.*]]
+; CHECK: default_dest:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %switch_bb
+
+switch_bb:
+ %phi = phi i32 [ 0, %entry ], [ 1, %case1 ], [ %phi_case2, %case2end ]
+ switch i32 %phi, label %default_dest [
+ i32 0, label %case1
+ i32 1, label %case2
+ ]
+
+case1:
+ br label %switch_bb
+
+case2:
+ br i1 %c1, label %case2then, label %case2end
+
+case2then:
+ br label %case2end
+
+case2end:
+ %phi_case2 = phi i32 [ 2, %case2 ] , [ 3, %case2then ]
+ call void @do_something()
+ call void @user(i32 %phi_case2)
+ br label %switch_bb
+
+default_dest:
+ ret void
+}
+
+define void @equivalent_only_cases(i1 %c1) {
+; CHECK-LABEL: define void @equivalent_only_cases(
+; CHECK-SAME: i1 [[C1:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[SWITCH_BB:%.*]]
+; CHECK: switch_bb:
+; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ poison, [[CASE2END:%.*]] ]
+; CHECK-NEXT: switch i32 [[PHI]], label [[DEFAULT_DEST:%.*]] [
+; CHECK-NEXT: i32 0, label [[CASE1:%.*]]
+; CHECK-NEXT: i32 1, label [[CASE2:%.*]]
+; CHECK-NEXT: i32 2, label [[CASE1]]
+; CHECK-NEXT: i32 3, label [[CASE1]]
+; CHECK-NEXT: ]
+; CHECK: switch_bb.jt3:
+; CHECK-NEXT: [[PHI_JT3:%.*]] = phi i32 [ [[PHI_CASE2_JT3:%.*]], [[CASE2END_JT3:%.*]] ]
+; CHECK-NEXT: br label [[CASE1]]
+; CHECK: switch_bb.jt2:
+; CHECK-NEXT: [[PHI_JT2:%.*]] = phi i32 [ [[PHI_CASE2_JT2:%.*]], [[CASE2END_JT2:%.*]] ]
+; CHECK-NEXT: br label [[CASE1]]
+; CHECK: switch_bb.jt1:
+; CHECK-NEXT: [[PHI_JT1:%.*]] = phi i32 [ 1, [[CASE1]] ]
+; CHECK-NEXT: br label [[CASE2]]
+; CHECK: case1:
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT1:%.*]]
+; CHECK: case2:
+; CHECK-NEXT: br i1 [[C1]], label [[CASE2THEN:%.*]], label [[CASE2END_JT2]]
+; CHECK: case2then:
+; CHECK-NEXT: br label [[CASE2END_JT3]]
+; CHECK: case2end:
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB]]
+; CHECK: case2end.jt3:
+; CHECK-NEXT: [[PHI_CASE2_JT3]] = phi i32 [ 3, [[CASE2THEN]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT3:%.*]]
+; CHECK: case2end.jt2:
+; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT2:%.*]]
+; CHECK: default_dest:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %switch_bb
+
+switch_bb:
+ %phi = phi i32 [ 0, %entry ], [ 1, %case1 ], [ %phi_case2, %case2end ]
+ switch i32 %phi, label %default_dest [
+ i32 0, label %case1
+ i32 1, label %case2
+ i32 2, label %case1
+ i32 3, label %case1
+ ]
+
+case1:
+ call void @do_something()
+ br label %switch_bb
+
+case2:
+ br i1 %c1, label %case2then, label %case2end
+
+case2then:
+ br label %case2end
+
+case2end:
+ %phi_case2 = phi i32 [ 2, %case2 ] , [ 3, %case2then ]
+ call void @do_something()
+ br label %switch_bb
+
+default_dest:
+ ret void
+}
+
+define void @equivalent_both_case_and_default(i1 %c1, i1 %c2) {
+; CHECK-LABEL: define void @equivalent_both_case_and_default(
+; CHECK-SAME: i1 [[C1:%.*]], i1 [[C2:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[SWITCH_BB:%.*]]
+; CHECK: switch_bb:
+; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ poison, [[CASE2END:%.*]] ]
+; CHECK-NEXT: switch i32 [[PHI]], label [[DEFAULT_DEST:%.*]] [
+; CHECK-NEXT: i32 0, label [[CASE1:%.*]]
+; CHECK-NEXT: i32 1, label [[CASE2:%.*]]
+; CHECK-NEXT: i32 2, label [[CASE1]]
+; CHECK-NEXT: i32 3, label [[CASE1]]
+; CHECK-NEXT: ]
+; CHECK: switch_bb.jt5:
+; CHECK-NEXT: [[PHI_JT5:%.*]] = phi i32 [ [[PHI_CASE2_JT5:%.*]], [[CASE2END_JT5:%.*]] ]
+; CHECK-NEXT: br label [[DEFAULT_DEST]]
+; CHECK: switch_bb.jt4:
+; CHECK-NEXT: [[PHI_JT4:%.*]] = phi i32 [ [[PHI_CASE2_JT4:%.*]], [[CASE2END_JT4:%.*]] ]
+; CHECK-NEXT: br label [[DEFAULT_DEST]]
+; CHECK: switch_bb.jt3:
+; CHECK-NEXT: [[PHI_JT3:%.*]] = phi i32 [ [[PHI_CASE2_JT3:%.*]], [[CASE2END_JT3:%.*]] ]
+; CHECK-NEXT: br label [[CASE1]]
+; CHECK: switch_bb.jt2:
+; CHECK-NEXT: [[PHI_JT2:%.*]] = phi i32 [ [[PHI_CASE2_JT2:%.*]], [[CASE2END_JT2:%.*]] ]
+; CHECK-NEXT: br label [[CASE1]]
+; CHECK: switch_bb.jt1:
+; CHECK-NEXT: [[PHI_JT1:%.*]] = phi i32 [ 1, [[CASE1]] ]
+; CHECK-NEXT: br label [[CASE2]]
+; CHECK: case1:
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT1:%.*]]
+; CHECK: case2:
+; CHECK-NEXT: br i1 [[C1]], label [[CASE2THEN:%.*]], label [[CASE2END_JT2]]
+; CHECK: case2then:
+; CHECK-NEXT: br i1 [[C2]], label [[CASE2THEN2:%.*]], label [[CASE2END_JT3]]
+; CHECK: case2then2:
+; CHECK-NEXT: br i1 [[C2]], label [[CASE2THEN3:%.*]], label [[CASE2END_JT4]]
+; CHECK: case2then3:
+; CHECK-NEXT: br label [[CASE2END_JT5]]
+; CHECK: case2end:
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB]]
+; CHECK: case2end.jt5:
+; CHECK-NEXT: [[PHI_CASE2_JT5]] = phi i32 [ 5, [[CASE2THEN3]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT5:%.*]]
+; CHECK: case2end.jt4:
+; CHECK-NEXT: [[PHI_CASE2_JT4]] = phi i32 [ 4, [[CASE2THEN2]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT4:%.*]]
+; CHECK: case2end.jt3:
+; CHECK-NEXT: [[PHI_CASE2_JT3]] = phi i32 [ 3, [[CASE2THEN]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT3:%.*]]
+; CHECK: case2end.jt2:
+; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ]
+; CHECK-NEXT: call void @do_something()
+; CHECK-NEXT: br label [[SWITCH_BB_JT2:%.*]]
+; CHECK: default_dest:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %switch_bb
+
+switch_bb:
+ %phi = phi i32 [ 0, %entry ], [ 1, %case1 ], [ %phi_case2, %case2end ]
+ switch i32 %phi, label %default_dest [
+ i32 0, label %case1
+ i32 1, label %case2
+ i32 2, label %case1
+ i32 3, label %case1
+ ]
+
+case1:
+ call void @do_something()
+ br label %switch_bb
+
+case2:
+ br i1 %c1, label %case2then, label %case2end
+
+case2then:
+ br i1 %c2, label %case2then2, label %case2end
+
+case2then2:
+ br i1 %c2, label %case2then3, label %case2end
+
+case2then3:
+ br label %case2end
+
+case2end:
+ %phi_case2 = phi i32 [ 2, %case2 ], [ 3, %case2then ], [ 4, %case2then2 ], [ 5, %case2then3 ]
+ call void @do_something()
+ br label %switch_bb
+
+default_dest:
+ ret void
+}
>From eb7f705207c07093ed4432534120da8d89772e0e Mon Sep 17 00:00:00 2001
From: XChy <xxs_chy at outlook.com>
Date: Wed, 8 Oct 2025 17:15:22 +0800
Subject: [PATCH 2/2] [DFAJumpThreading] Unify equivalent states
---
.../Transforms/Scalar/DFAJumpThreading.cpp | 138 +++++++++++-------
.../DFAJumpThreading/equivalent-states.ll | 60 ++------
2 files changed, 97 insertions(+), 101 deletions(-)
diff --git a/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp b/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
index ae34b4e6fbacf..92c573d53c8ee 100644
--- a/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
@@ -384,6 +384,22 @@ inline raw_ostream &operator<<(raw_ostream &OS, const PathType &Path) {
return OS;
}
+/// Helper to get the successor corresponding to a particular case value for
+/// a switch statement.
+static BasicBlock *getNextCaseSuccessor(SwitchInst *Switch,
+ const APInt &NextState) {
+ BasicBlock *NextCase = nullptr;
+ for (auto Case : Switch->cases()) {
+ if (Case.getCaseValue()->getValue() == NextState) {
+ NextCase = Case.getCaseSuccessor();
+ break;
+ }
+ }
+ if (!NextCase)
+ NextCase = Switch->getDefaultDest();
+ return NextCase;
+}
+
namespace {
/// ThreadingPath is a path in the control flow of a loop that can be threaded
/// by cloning necessary basic blocks and replacing conditional branches with
@@ -396,6 +412,10 @@ struct ThreadingPath {
ExitVal = V->getValue();
IsExitValSet = true;
}
+ void setExitValue(const APInt &V) {
+ ExitVal = V;
+ IsExitValSet = true;
+ }
bool isExitValueSet() const { return IsExitValSet; }
/// Determinator is the basic block that determines the next state of the DFA.
@@ -578,44 +598,8 @@ struct AllSwitchPaths {
BasicBlock *getSwitchBlock() { return SwitchBlock; }
void run() {
- StateDefMap StateDef = getStateDefMap();
- if (StateDef.empty()) {
- ORE->emit([&]() {
- return OptimizationRemarkMissed(DEBUG_TYPE, "SwitchNotPredictable",
- Switch)
- << "Switch instruction is not predictable.";
- });
- return;
- }
-
- auto *SwitchPhi = cast<PHINode>(Switch->getOperand(0));
- auto *SwitchPhiDefBB = SwitchPhi->getParent();
- VisitedBlocks VB;
- // Get paths from the determinator BBs to SwitchPhiDefBB
- std::vector<ThreadingPath> PathsToPhiDef =
- getPathsFromStateDefMap(StateDef, SwitchPhi, VB, MaxNumPaths);
- if (SwitchPhiDefBB == SwitchBlock || PathsToPhiDef.empty()) {
- TPaths = std::move(PathsToPhiDef);
- return;
- }
-
- assert(MaxNumPaths >= PathsToPhiDef.size() && !PathsToPhiDef.empty());
- auto PathsLimit = MaxNumPaths / PathsToPhiDef.size();
- // Find and append paths from SwitchPhiDefBB to SwitchBlock.
- PathsType PathsToSwitchBB =
- paths(SwitchPhiDefBB, SwitchBlock, VB, /* PathDepth = */ 1, PathsLimit);
- if (PathsToSwitchBB.empty())
- return;
-
- std::vector<ThreadingPath> TempList;
- for (const ThreadingPath &Path : PathsToPhiDef) {
- for (const PathType &PathToSw : PathsToSwitchBB) {
- ThreadingPath PathCopy(Path);
- PathCopy.appendExcludingFirst(PathToSw);
- TempList.push_back(PathCopy);
- }
- }
- TPaths = std::move(TempList);
+ findTPaths();
+ unifyTPaths();
}
private:
@@ -807,6 +791,69 @@ struct AllSwitchPaths {
return Res;
}
+ // Find all threadable paths.
+ void findTPaths() {
+ StateDefMap StateDef = getStateDefMap();
+ if (StateDef.empty()) {
+ ORE->emit([&]() {
+ return OptimizationRemarkMissed(DEBUG_TYPE, "SwitchNotPredictable",
+ Switch)
+ << "Switch instruction is not predictable.";
+ });
+ return;
+ }
+
+ auto *SwitchPhi = cast<PHINode>(Switch->getOperand(0));
+ auto *SwitchPhiDefBB = SwitchPhi->getParent();
+ VisitedBlocks VB;
+ // Get paths from the determinator BBs to SwitchPhiDefBB
+ std::vector<ThreadingPath> PathsToPhiDef =
+ getPathsFromStateDefMap(StateDef, SwitchPhi, VB, MaxNumPaths);
+ if (SwitchPhiDefBB == SwitchBlock || PathsToPhiDef.empty()) {
+ TPaths = std::move(PathsToPhiDef);
+ return;
+ }
+
+ assert(MaxNumPaths >= PathsToPhiDef.size() && !PathsToPhiDef.empty());
+ auto PathsLimit = MaxNumPaths / PathsToPhiDef.size();
+ // Find and append paths from SwitchPhiDefBB to SwitchBlock.
+ PathsType PathsToSwitchBB =
+ paths(SwitchPhiDefBB, SwitchBlock, VB, /* PathDepth = */ 1, PathsLimit);
+ if (PathsToSwitchBB.empty())
+ return;
+
+ std::vector<ThreadingPath> TempList;
+ for (const ThreadingPath &Path : PathsToPhiDef) {
+ for (const PathType &PathToSw : PathsToSwitchBB) {
+ ThreadingPath PathCopy(Path);
+ PathCopy.appendExcludingFirst(PathToSw);
+ TempList.push_back(PathCopy);
+ }
+ }
+ TPaths = std::move(TempList);
+ }
+
+ // Two states are equivalent if they have the same switch destination.
+ // Unify the states in different threading path if the states are equivalent.
+ void unifyTPaths() {
+ llvm::SmallDenseMap<BasicBlock *, APInt> DestToState;
+ for (ThreadingPath &Path : TPaths) {
+ APInt NextState = Path.getExitValue();
+ BasicBlock *Dest = getNextCaseSuccessor(Switch, NextState);
+ auto StateIt = DestToState.find(Dest);
+ if (StateIt == DestToState.end()) {
+ DestToState.insert({Dest, NextState});
+ continue;
+ }
+
+ if (NextState != StateIt->second) {
+ LLVM_DEBUG(dbgs() << "Next state in " << Path << " is equivalent to "
+ << StateIt->second << "\n");
+ Path.setExitValue(StateIt->second);
+ }
+ }
+ }
+
unsigned NumVisited = 0;
SwitchInst *Switch;
BasicBlock *SwitchBlock;
@@ -1339,21 +1386,6 @@ struct TransformDFA {
return It != ClonedBBs.end() ? (*It).BB : nullptr;
}
- /// Helper to get the successor corresponding to a particular case value for
- /// a switch statement.
- BasicBlock *getNextCaseSuccessor(SwitchInst *Switch, const APInt &NextState) {
- BasicBlock *NextCase = nullptr;
- for (auto Case : Switch->cases()) {
- if (Case.getCaseValue()->getValue() == NextState) {
- NextCase = Case.getCaseSuccessor();
- break;
- }
- }
- if (!NextCase)
- NextCase = Switch->getDefaultDest();
- return NextCase;
- }
-
/// Returns true if IncomingBB is a predecessor of BB.
bool isPredecessor(BasicBlock *BB, BasicBlock *IncomingBB) {
return llvm::is_contained(predecessors(BB), IncomingBB);
diff --git a/llvm/test/Transforms/DFAJumpThreading/equivalent-states.ll b/llvm/test/Transforms/DFAJumpThreading/equivalent-states.ll
index 36c07a7fa478f..4555dfb87330f 100644
--- a/llvm/test/Transforms/DFAJumpThreading/equivalent-states.ll
+++ b/llvm/test/Transforms/DFAJumpThreading/equivalent-states.ll
@@ -15,9 +15,6 @@ define void @equivalent_on_default(i1 %c1) {
; CHECK-NEXT: i32 0, label [[CASE1:%.*]]
; CHECK-NEXT: i32 1, label [[CASE2:%.*]]
; CHECK-NEXT: ]
-; CHECK: switch_bb.jt3:
-; CHECK-NEXT: [[PHI_JT3:%.*]] = phi i32 [ [[PHI_CASE2_JT3:%.*]], [[CASE2END_JT3:%.*]] ]
-; CHECK-NEXT: br label [[DEFAULT_DEST]]
; CHECK: switch_bb.jt2:
; CHECK-NEXT: [[PHI_JT2:%.*]] = phi i32 [ [[PHI_CASE2_JT2:%.*]], [[CASE2END_JT2:%.*]] ]
; CHECK-NEXT: br label [[DEFAULT_DEST]]
@@ -29,16 +26,12 @@ define void @equivalent_on_default(i1 %c1) {
; CHECK: case2:
; CHECK-NEXT: br i1 [[C1]], label [[CASE2THEN:%.*]], label [[CASE2END_JT2]]
; CHECK: case2then:
-; CHECK-NEXT: br label [[CASE2END_JT3]]
+; CHECK-NEXT: br label [[CASE2END_JT2]]
; CHECK: case2end:
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: br label [[SWITCH_BB]]
-; CHECK: case2end.jt3:
-; CHECK-NEXT: [[PHI_CASE2_JT3]] = phi i32 [ 3, [[CASE2THEN]] ]
-; CHECK-NEXT: call void @do_something()
-; CHECK-NEXT: br label [[SWITCH_BB_JT3:%.*]]
; CHECK: case2end.jt2:
-; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ]
+; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ], [ 3, [[CASE2THEN]] ]
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: br label [[SWITCH_BB_JT2:%.*]]
; CHECK: default_dest:
@@ -83,9 +76,6 @@ define void @equivalent_on_default_user(i1 %c1) {
; CHECK-NEXT: i32 0, label [[CASE1:%.*]]
; CHECK-NEXT: i32 1, label [[CASE2:%.*]]
; CHECK-NEXT: ]
-; CHECK: switch_bb.jt3:
-; CHECK-NEXT: [[PHI_JT3:%.*]] = phi i32 [ [[PHI_CASE2_JT3:%.*]], [[CASE2END_JT3:%.*]] ]
-; CHECK-NEXT: br label [[DEFAULT_DEST]]
; CHECK: switch_bb.jt2:
; CHECK-NEXT: [[PHI_JT2:%.*]] = phi i32 [ [[PHI_CASE2_JT2:%.*]], [[CASE2END_JT2:%.*]] ]
; CHECK-NEXT: br label [[DEFAULT_DEST]]
@@ -97,18 +87,13 @@ define void @equivalent_on_default_user(i1 %c1) {
; CHECK: case2:
; CHECK-NEXT: br i1 [[C1]], label [[CASE2THEN:%.*]], label [[CASE2END_JT2]]
; CHECK: case2then:
-; CHECK-NEXT: br label [[CASE2END_JT3]]
+; CHECK-NEXT: br label [[CASE2END_JT2]]
; CHECK: case2end:
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: call void @user(i32 poison)
; CHECK-NEXT: br label [[SWITCH_BB]]
-; CHECK: case2end.jt3:
-; CHECK-NEXT: [[PHI_CASE2_JT3]] = phi i32 [ 3, [[CASE2THEN]] ]
-; CHECK-NEXT: call void @do_something()
-; CHECK-NEXT: call void @user(i32 [[PHI_CASE2_JT3]])
-; CHECK-NEXT: br label [[SWITCH_BB_JT3:%.*]]
; CHECK: case2end.jt2:
-; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ]
+; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ], [ 3, [[CASE2THEN]] ]
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: call void @user(i32 [[PHI_CASE2_JT2]])
; CHECK-NEXT: br label [[SWITCH_BB_JT2:%.*]]
@@ -157,9 +142,6 @@ define void @equivalent_only_cases(i1 %c1) {
; CHECK-NEXT: i32 2, label [[CASE1]]
; CHECK-NEXT: i32 3, label [[CASE1]]
; CHECK-NEXT: ]
-; CHECK: switch_bb.jt3:
-; CHECK-NEXT: [[PHI_JT3:%.*]] = phi i32 [ [[PHI_CASE2_JT3:%.*]], [[CASE2END_JT3:%.*]] ]
-; CHECK-NEXT: br label [[CASE1]]
; CHECK: switch_bb.jt2:
; CHECK-NEXT: [[PHI_JT2:%.*]] = phi i32 [ [[PHI_CASE2_JT2:%.*]], [[CASE2END_JT2:%.*]] ]
; CHECK-NEXT: br label [[CASE1]]
@@ -172,16 +154,12 @@ define void @equivalent_only_cases(i1 %c1) {
; CHECK: case2:
; CHECK-NEXT: br i1 [[C1]], label [[CASE2THEN:%.*]], label [[CASE2END_JT2]]
; CHECK: case2then:
-; CHECK-NEXT: br label [[CASE2END_JT3]]
+; CHECK-NEXT: br label [[CASE2END_JT2]]
; CHECK: case2end:
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: br label [[SWITCH_BB]]
-; CHECK: case2end.jt3:
-; CHECK-NEXT: [[PHI_CASE2_JT3]] = phi i32 [ 3, [[CASE2THEN]] ]
-; CHECK-NEXT: call void @do_something()
-; CHECK-NEXT: br label [[SWITCH_BB_JT3:%.*]]
; CHECK: case2end.jt2:
-; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ]
+; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ], [ 3, [[CASE2THEN]] ]
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: br label [[SWITCH_BB_JT2:%.*]]
; CHECK: default_dest:
@@ -231,15 +209,9 @@ define void @equivalent_both_case_and_default(i1 %c1, i1 %c2) {
; CHECK-NEXT: i32 2, label [[CASE1]]
; CHECK-NEXT: i32 3, label [[CASE1]]
; CHECK-NEXT: ]
-; CHECK: switch_bb.jt5:
-; CHECK-NEXT: [[PHI_JT5:%.*]] = phi i32 [ [[PHI_CASE2_JT5:%.*]], [[CASE2END_JT5:%.*]] ]
-; CHECK-NEXT: br label [[DEFAULT_DEST]]
; CHECK: switch_bb.jt4:
-; CHECK-NEXT: [[PHI_JT4:%.*]] = phi i32 [ [[PHI_CASE2_JT4:%.*]], [[CASE2END_JT4:%.*]] ]
-; CHECK-NEXT: br label [[DEFAULT_DEST]]
-; CHECK: switch_bb.jt3:
; CHECK-NEXT: [[PHI_JT3:%.*]] = phi i32 [ [[PHI_CASE2_JT3:%.*]], [[CASE2END_JT3:%.*]] ]
-; CHECK-NEXT: br label [[CASE1]]
+; CHECK-NEXT: br label [[DEFAULT_DEST]]
; CHECK: switch_bb.jt2:
; CHECK-NEXT: [[PHI_JT2:%.*]] = phi i32 [ [[PHI_CASE2_JT2:%.*]], [[CASE2END_JT2:%.*]] ]
; CHECK-NEXT: br label [[CASE1]]
@@ -252,28 +224,20 @@ define void @equivalent_both_case_and_default(i1 %c1, i1 %c2) {
; CHECK: case2:
; CHECK-NEXT: br i1 [[C1]], label [[CASE2THEN:%.*]], label [[CASE2END_JT2]]
; CHECK: case2then:
-; CHECK-NEXT: br i1 [[C2]], label [[CASE2THEN2:%.*]], label [[CASE2END_JT3]]
+; CHECK-NEXT: br i1 [[C2]], label [[CASE2THEN2:%.*]], label [[CASE2END_JT2]]
; CHECK: case2then2:
-; CHECK-NEXT: br i1 [[C2]], label [[CASE2THEN3:%.*]], label [[CASE2END_JT4]]
+; CHECK-NEXT: br i1 [[C2]], label [[CASE2THEN3:%.*]], label [[CASE2END_JT3]]
; CHECK: case2then3:
-; CHECK-NEXT: br label [[CASE2END_JT5]]
+; CHECK-NEXT: br label [[CASE2END_JT3]]
; CHECK: case2end:
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: br label [[SWITCH_BB]]
-; CHECK: case2end.jt5:
-; CHECK-NEXT: [[PHI_CASE2_JT5]] = phi i32 [ 5, [[CASE2THEN3]] ]
-; CHECK-NEXT: call void @do_something()
-; CHECK-NEXT: br label [[SWITCH_BB_JT5:%.*]]
; CHECK: case2end.jt4:
-; CHECK-NEXT: [[PHI_CASE2_JT4]] = phi i32 [ 4, [[CASE2THEN2]] ]
-; CHECK-NEXT: call void @do_something()
-; CHECK-NEXT: br label [[SWITCH_BB_JT4:%.*]]
-; CHECK: case2end.jt3:
-; CHECK-NEXT: [[PHI_CASE2_JT3]] = phi i32 [ 3, [[CASE2THEN]] ]
+; CHECK-NEXT: [[PHI_CASE2_JT3]] = phi i32 [ 4, [[CASE2THEN2]] ], [ 5, [[CASE2THEN3]] ]
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: br label [[SWITCH_BB_JT3:%.*]]
; CHECK: case2end.jt2:
-; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ]
+; CHECK-NEXT: [[PHI_CASE2_JT2]] = phi i32 [ 2, [[CASE2]] ], [ 3, [[CASE2THEN]] ]
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: br label [[SWITCH_BB_JT2:%.*]]
; CHECK: default_dest:
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