[llvm] [DFAJumpThreading] Unfold select to the incoming block of phi user (PR #160987)
Hongyu Chen via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 1 01:54:24 PDT 2025
https://github.com/XChy updated https://github.com/llvm/llvm-project/pull/160987
>From 82ec2a7ddd7edbef7a97d864bf65a5fddf5bf909 Mon Sep 17 00:00:00 2001
From: XChy <xxs_chy at outlook.com>
Date: Sat, 27 Sep 2025 15:16:10 +0800
Subject: [PATCH 1/3] [DFAJumpThreading] Unfold select to the incoming block of
phi user
---
.../Transforms/Scalar/DFAJumpThreading.cpp | 10 +--
.../dfa-jump-threading-transform.ll | 40 ++++++-----
.../DFAJumpThreading/dfa-unfold-select.ll | 70 +++++++++++++++++++
3 files changed, 98 insertions(+), 22 deletions(-)
diff --git a/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp b/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
index 944b253e0f5e7..1da312c5a85ff 100644
--- a/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
@@ -190,12 +190,12 @@ void unfold(DomTreeUpdater *DTU, LoopInfo *LI, SelectInstToUnfold SIToUnfold,
std::vector<BasicBlock *> *NewBBs) {
SelectInst *SI = SIToUnfold.getInst();
PHINode *SIUse = SIToUnfold.getUse();
- BasicBlock *StartBlock = SI->getParent();
+ assert(SI->hasOneUse());
+ // The select may come indirectly, instead of from where it is defined.
+ BasicBlock *StartBlock = SIUse->getIncomingBlock(SI->user_begin().getUse());
BranchInst *StartBlockTerm =
dyn_cast<BranchInst>(StartBlock->getTerminator());
-
assert(StartBlockTerm);
- assert(SI->hasOneUse());
if (StartBlockTerm->isUnconditional()) {
BasicBlock *EndBlock = StartBlock->getUniqueSuccessor();
@@ -332,7 +332,7 @@ void unfold(DomTreeUpdater *DTU, LoopInfo *LI, SelectInstToUnfold SIToUnfold,
}
// Preserve loop info
- if (Loop *L = LI->getLoopFor(SI->getParent())) {
+ if (Loop *L = LI->getLoopFor(StartBlock)) {
for (BasicBlock *NewBB : *NewBBs)
L->addBasicBlockToLoop(NewBB, *LI);
}
@@ -533,6 +533,8 @@ struct MainSwitch {
return false;
// Only fold the select coming from directly where it is defined.
+ // TODO: We have dealt with the select coming indirectly now. This
+ // constraint can be relaxed.
PHINode *PHIUser = dyn_cast<PHINode>(SIUse);
if (PHIUser && PHIUser->getIncomingBlock(*SI->use_begin()) != SIBB)
return false;
diff --git a/llvm/test/Transforms/DFAJumpThreading/dfa-jump-threading-transform.ll b/llvm/test/Transforms/DFAJumpThreading/dfa-jump-threading-transform.ll
index cba1ba8dde768..6d9bd1fae11d0 100644
--- a/llvm/test/Transforms/DFAJumpThreading/dfa-jump-threading-transform.ll
+++ b/llvm/test/Transforms/DFAJumpThreading/dfa-jump-threading-transform.ll
@@ -304,25 +304,27 @@ end:
define void @pr106083_invalidBBarg_fold(i1 %cmp1, i1 %cmp2, i1 %not, ptr %d) {
; CHECK-LABEL: @pr106083_invalidBBarg_fold(
; CHECK-NEXT: bb:
-; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[BB1:%.*]], label [[SEL_SI_UNFOLD_FALSE:%.*]]
-; CHECK: sel.si.unfold.false:
-; CHECK-NEXT: [[DOTSI_UNFOLD_PHI1:%.*]] = phi i32 [ 1, [[BB:%.*]] ]
-; CHECK-NEXT: br label [[BB1]]
+; CHECK-NEXT: br label [[BB1:%.*]]
; CHECK: BB1:
-; CHECK-NEXT: [[I:%.*]] = phi i16 [ 0, [[BB1_BACKEDGE:%.*]] ], [ 0, [[BB]] ], [ 1, [[BB7:%.*]] ], [ 0, [[SEL_SI_UNFOLD_FALSE]] ], [ 1, [[BB7_JT0:%.*]] ]
-; CHECK-NEXT: [[SEL_SI_UNFOLD_PHI:%.*]] = phi i32 [ [[SEL_SI_UNFOLD_PHI]], [[BB1_BACKEDGE]] ], [ [[SEL_SI_UNFOLD_PHI]], [[BB7]] ], [ 0, [[BB]] ], [ [[DOTSI_UNFOLD_PHI1]], [[SEL_SI_UNFOLD_FALSE]] ], [ [[SEL_SI_UNFOLD_PHI]], [[BB7_JT0]] ]
+; CHECK-NEXT: [[I:%.*]] = phi i16 [ 0, [[BB1_BACKEDGE:%.*]] ], [ 0, [[BB:%.*]] ], [ 1, [[BB9:%.*]] ], [ 1, [[BB7_JT0:%.*]] ]
; CHECK-NEXT: br i1 [[NOT:%.*]], label [[BB7_JT0]], label [[BB2:%.*]]
; CHECK: BB2:
; CHECK-NEXT: store i16 0, ptr [[D:%.*]], align 2
-; CHECK-NEXT: br i1 [[CMP2:%.*]], label [[BB7]], label [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0:%.*]]
+; CHECK-NEXT: br i1 [[CMP2:%.*]], label [[BB7:%.*]], label [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0:%.*]]
; CHECK: spec.select.si.unfold.false:
-; CHECK-NEXT: br label [[BB7]]
+; CHECK-NEXT: br label [[BB9]]
; CHECK: spec.select.si.unfold.false.jt0:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ 0, [[BB2]] ]
; CHECK-NEXT: br label [[BB7_JT0]]
+; CHECK: sel.si.unfold.true:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI1:%.*]] = phi i32 [ 0, [[BB2]] ]
+; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[BB9]], label [[SEL_SI_UNFOLD_FALSE:%.*]]
+; CHECK: sel.si.unfold.false:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI2:%.*]] = phi i32 [ 1, [[BB7]] ]
+; CHECK-NEXT: br label [[BB9]]
; CHECK: BB7:
-; CHECK-NEXT: [[D_PROMOTED4:%.*]] = phi i16 [ 1, [[BB2]] ], [ 1, [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]] ]
-; CHECK-NEXT: [[_3:%.*]] = phi i32 [ [[SEL_SI_UNFOLD_PHI]], [[BB2]] ], [ poison, [[SPEC_SELECT_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: [[D_PROMOTED4:%.*]] = phi i16 [ 1, [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]] ], [ 1, [[BB7]] ], [ 1, [[SEL_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: [[_3:%.*]] = phi i32 [ poison, [[SPEC_SELECT_SI_UNFOLD_FALSE]] ], [ [[DOTSI_UNFOLD_PHI1]], [[BB7]] ], [ [[DOTSI_UNFOLD_PHI2]], [[SEL_SI_UNFOLD_FALSE]] ]
; CHECK-NEXT: switch i32 [[_3]], label [[BB1_BACKEDGE]] [
; CHECK-NEXT: i32 0, label [[BB1]]
; CHECK-NEXT: i32 1, label [[BB8:%.*]]
@@ -367,24 +369,26 @@ BB8: ; preds = %BB7
define void @pr106083_select_dead_uses(i1 %cmp1, i1 %not, ptr %p) {
; CHECK-LABEL: @pr106083_select_dead_uses(
; CHECK-NEXT: bb:
-; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[DOTLOOPEXIT6:%.*]], label [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]]
-; CHECK: spec.select.si.unfold.false:
-; CHECK-NEXT: [[DOTSI_UNFOLD_PHI1:%.*]] = phi i32 [ 1, [[BB:%.*]] ]
-; CHECK-NEXT: br label [[DOTLOOPEXIT6]]
+; CHECK-NEXT: br label [[DOTLOOPEXIT6:%.*]]
; CHECK: .loopexit6:
-; CHECK-NEXT: [[SPEC_SELECT_SI_UNFOLD_PHI:%.*]] = phi i32 [ [[SPEC_SELECT_SI_UNFOLD_PHI]], [[SELECT_UNFOLD:%.*]] ], [ 0, [[BB]] ], [ [[DOTSI_UNFOLD_PHI1]], [[SPEC_SELECT_SI_UNFOLD_FALSE]] ]
; CHECK-NEXT: br i1 [[NOT:%.*]], label [[SELECT_UNFOLD_JT0:%.*]], label [[BB1:%.*]]
; CHECK: bb1:
; CHECK-NEXT: [[I:%.*]] = load i32, ptr [[P:%.*]], align 4
; CHECK-NEXT: [[NOT2:%.*]] = icmp eq i32 0, 0
-; CHECK-NEXT: br i1 [[NOT2]], label [[SELECT_UNFOLD]], label [[SPEC_SELECT7_SI_UNFOLD_FALSE_JT0:%.*]]
+; CHECK-NEXT: br i1 [[NOT2]], label [[SELECT_UNFOLD:%.*]], label [[SPEC_SELECT7_SI_UNFOLD_FALSE_JT0:%.*]]
; CHECK: spec.select7.si.unfold.false:
-; CHECK-NEXT: br label [[SELECT_UNFOLD]]
+; CHECK-NEXT: br label [[SELECT_UNFOLD1:%.*]]
; CHECK: spec.select7.si.unfold.false.jt0:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ 0, [[BB1]] ]
; CHECK-NEXT: br label [[SELECT_UNFOLD_JT0]]
+; CHECK: spec.select.si.unfold.true:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI1:%.*]] = phi i32 [ 0, [[BB1]] ]
+; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[SELECT_UNFOLD1]], label [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]]
+; CHECK: spec.select.si.unfold.false:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI2:%.*]] = phi i32 [ 1, [[SELECT_UNFOLD]] ]
+; CHECK-NEXT: br label [[SELECT_UNFOLD1]]
; CHECK: select.unfold:
-; CHECK-NEXT: [[_2:%.*]] = phi i32 [ [[SPEC_SELECT_SI_UNFOLD_PHI]], [[BB1]] ], [ poison, [[SPEC_SELECT7_SI_UNFOLD_FALSE:%.*]] ]
+; CHECK-NEXT: [[_2:%.*]] = phi i32 [ poison, [[SPEC_SELECT7_SI_UNFOLD_FALSE:%.*]] ], [ [[DOTSI_UNFOLD_PHI1]], [[SELECT_UNFOLD]] ], [ [[DOTSI_UNFOLD_PHI2]], [[SPEC_SELECT_SI_UNFOLD_FALSE]] ]
; CHECK-NEXT: switch i32 [[_2]], label [[BB2:%.*]] [
; CHECK-NEXT: i32 0, label [[DOTPREHEADER_PREHEADER:%.*]]
; CHECK-NEXT: i32 1, label [[DOTLOOPEXIT6]]
diff --git a/llvm/test/Transforms/DFAJumpThreading/dfa-unfold-select.ll b/llvm/test/Transforms/DFAJumpThreading/dfa-unfold-select.ll
index 93872c3938768..7fc70e838f2fd 100644
--- a/llvm/test/Transforms/DFAJumpThreading/dfa-unfold-select.ll
+++ b/llvm/test/Transforms/DFAJumpThreading/dfa-unfold-select.ll
@@ -463,3 +463,73 @@ unreachable:
sw.bb: ; preds = %if.end
br label %while.cond
}
+
+define i16 @pr160250() {
+; CHECK-LABEL: @pr160250(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[FOR_COND48:%.*]]
+; CHECK: for.cond48:
+; CHECK-NEXT: br i1 false, label [[CLEANUP87_JT0:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.else:
+; CHECK-NEXT: br i1 false, label [[DOT6_SI_UNFOLD_TRUE:%.*]], label [[DOT5_SI_UNFOLD_TRUE:%.*]]
+; CHECK: .5.si.unfold.true:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI1:%.*]] = phi i32 [ 0, [[IF_ELSE]] ]
+; CHECK-NEXT: br i1 false, label [[SPEC_SELECT1_SI_UNFOLD_TRUE:%.*]], label [[DOT5_SI_UNFOLD_FALSE:%.*]]
+; CHECK: .5.si.unfold.false:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI2:%.*]] = phi i32 [ 0, [[DOT5_SI_UNFOLD_TRUE]] ]
+; CHECK-NEXT: br label [[SPEC_SELECT1_SI_UNFOLD_TRUE]]
+; CHECK: spec.select1.si.unfold.true:
+; CHECK-NEXT: [[DOT5_SI_UNFOLD_PHI:%.*]] = phi i32 [ [[DOTSI_UNFOLD_PHI1]], [[DOT5_SI_UNFOLD_TRUE]] ], [ [[DOTSI_UNFOLD_PHI2]], [[DOT5_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: br i1 false, label [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]], label [[SPEC_SELECT1_SI_UNFOLD_FALSE_JT0:%.*]]
+; CHECK: spec.select1.si.unfold.false:
+; CHECK-NEXT: br label [[SPEC_SELECT_SI_UNFOLD_FALSE]]
+; CHECK: spec.select1.si.unfold.false.jt0:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ 0, [[SPEC_SELECT1_SI_UNFOLD_TRUE]] ]
+; CHECK-NEXT: br label [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0:%.*]]
+; CHECK: spec.select.si.unfold.false:
+; CHECK-NEXT: [[SPEC_SELECT1_SI_UNFOLD_PHI:%.*]] = phi i32 [ [[DOT5_SI_UNFOLD_PHI]], [[SPEC_SELECT1_SI_UNFOLD_TRUE]] ], [ poison, [[SPEC_SELECT1_SI_UNFOLD_FALSE:%.*]] ]
+; CHECK-NEXT: br label [[CLEANUP87:%.*]]
+; CHECK: spec.select.si.unfold.false.jt0:
+; CHECK-NEXT: [[SPEC_SELECT1_SI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ [[DOTSI_UNFOLD_PHI_JT0]], [[SPEC_SELECT1_SI_UNFOLD_FALSE_JT0]] ]
+; CHECK-NEXT: br label [[CLEANUP87_JT0]]
+; CHECK: .6.si.unfold.true:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI3:%.*]] = phi i32 [ 0, [[IF_ELSE]] ]
+; CHECK-NEXT: br i1 false, label [[CLEANUP87]], label [[DOT6_SI_UNFOLD_FALSE:%.*]]
+; CHECK: .6.si.unfold.false:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI4:%.*]] = phi i32 [ 0, [[DOT6_SI_UNFOLD_TRUE]] ]
+; CHECK-NEXT: br label [[CLEANUP87]]
+; CHECK: cleanup87:
+; CHECK-NEXT: [[CLEANUP_DEST_SLOT_3:%.*]] = phi i32 [ [[SPEC_SELECT1_SI_UNFOLD_PHI]], [[SPEC_SELECT_SI_UNFOLD_FALSE]] ], [ [[DOTSI_UNFOLD_PHI3]], [[DOT6_SI_UNFOLD_TRUE]] ], [ [[DOTSI_UNFOLD_PHI4]], [[DOT6_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: switch i32 [[CLEANUP_DEST_SLOT_3]], label [[FOR_COND48_BACKEDGE:%.*]] [
+; CHECK-NEXT: i32 0, label [[FOR_COND48_BACKEDGE]]
+; CHECK-NEXT: i32 1, label [[FOR_COND48_BACKEDGE]]
+; CHECK-NEXT: ]
+; CHECK: cleanup87.jt0:
+; CHECK-NEXT: [[CLEANUP_DEST_SLOT_3_JT0:%.*]] = phi i32 [ 0, [[FOR_COND48]] ], [ [[SPEC_SELECT1_SI_UNFOLD_PHI_JT0]], [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0]] ]
+; CHECK-NEXT: br label [[FOR_COND48_BACKEDGE]]
+; CHECK: for.cond48.backedge:
+; CHECK-NEXT: br label [[FOR_COND48]]
+;
+entry:
+ %.5 = select i1 false, i32 0, i32 0
+ %.6 = select i1 false, i32 0, i32 0
+ br label %for.cond48
+
+for.cond48: ; preds = %for.cond48.backedge, %entry
+ br i1 false, label %cleanup87, label %if.else
+
+if.else: ; preds = %for.cond48
+ %spec.select1 = select i1 false, i32 %.5, i32 0
+ %spec.select = select i1 false, i32 %.6, i32 %spec.select1
+ br label %cleanup87
+
+cleanup87: ; preds = %if.else, %for.cond48
+ %cleanup.dest.slot.3 = phi i32 [ 0, %for.cond48 ], [ %spec.select, %if.else ]
+ switch i32 %cleanup.dest.slot.3, label %for.cond48.backedge [
+ i32 0, label %for.cond48.backedge
+ i32 1, label %for.cond48.backedge
+ ]
+
+for.cond48.backedge: ; preds = %cleanup87, %cleanup87, %cleanup87
+ br label %for.cond48
+}
>From 3429823db698a431bd4ba5f09d2b32fc424c0efe Mon Sep 17 00:00:00 2001
From: XChy <xxs_chy at outlook.com>
Date: Sat, 27 Sep 2025 18:34:40 +0800
Subject: [PATCH 2/3] update tests
---
.../dfa-jump-threading-transform.ll | 33 ++++++++++++++-----
.../DFAJumpThreading/dfa-unfold-select.ll | 32 +++++++++++++-----
2 files changed, 48 insertions(+), 17 deletions(-)
diff --git a/llvm/test/Transforms/DFAJumpThreading/dfa-jump-threading-transform.ll b/llvm/test/Transforms/DFAJumpThreading/dfa-jump-threading-transform.ll
index 6d9bd1fae11d0..ad0568486396f 100644
--- a/llvm/test/Transforms/DFAJumpThreading/dfa-jump-threading-transform.ll
+++ b/llvm/test/Transforms/DFAJumpThreading/dfa-jump-threading-transform.ll
@@ -317,21 +317,30 @@ define void @pr106083_invalidBBarg_fold(i1 %cmp1, i1 %cmp2, i1 %not, ptr %d) {
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ 0, [[BB2]] ]
; CHECK-NEXT: br label [[BB7_JT0]]
; CHECK: sel.si.unfold.true:
+; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[BB9]], label [[SEL_SI_UNFOLD_FALSE_JT1:%.*]]
+; CHECK: sel.si.unfold.true.jt0:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI1:%.*]] = phi i32 [ 0, [[BB2]] ]
-; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[BB9]], label [[SEL_SI_UNFOLD_FALSE:%.*]]
+; CHECK-NEXT: br i1 [[CMP1]], label [[BB7_JT0]], label [[SEL_SI_UNFOLD_FALSE:%.*]]
; CHECK: sel.si.unfold.false:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI2:%.*]] = phi i32 [ 1, [[BB7]] ]
; CHECK-NEXT: br label [[BB9]]
+; CHECK: sel.si.unfold.false.jt1:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI2_JT1:%.*]] = phi i32 [ 1, [[SEL_SI_UNFOLD_TRUE:%.*]] ]
+; CHECK-NEXT: br label [[BB7_JT1:%.*]]
; CHECK: BB7:
-; CHECK-NEXT: [[D_PROMOTED4:%.*]] = phi i16 [ 1, [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]] ], [ 1, [[BB7]] ], [ 1, [[SEL_SI_UNFOLD_FALSE]] ]
-; CHECK-NEXT: [[_3:%.*]] = phi i32 [ poison, [[SPEC_SELECT_SI_UNFOLD_FALSE]] ], [ [[DOTSI_UNFOLD_PHI1]], [[BB7]] ], [ [[DOTSI_UNFOLD_PHI2]], [[SEL_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: [[D_PROMOTED4:%.*]] = phi i16 [ 1, [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]] ], [ 1, [[SEL_SI_UNFOLD_TRUE]] ], [ 1, [[SEL_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: [[_3:%.*]] = phi i32 [ poison, [[SPEC_SELECT_SI_UNFOLD_FALSE]] ], [ poison, [[SEL_SI_UNFOLD_TRUE]] ], [ [[DOTSI_UNFOLD_PHI2]], [[SEL_SI_UNFOLD_FALSE]] ]
; CHECK-NEXT: switch i32 [[_3]], label [[BB1_BACKEDGE]] [
; CHECK-NEXT: i32 0, label [[BB1]]
; CHECK-NEXT: i32 1, label [[BB8:%.*]]
; CHECK-NEXT: ]
+; CHECK: BB7.jt1:
+; CHECK-NEXT: [[D_PROMOTED4_JT1:%.*]] = phi i16 [ 1, [[SEL_SI_UNFOLD_FALSE_JT1]] ]
+; CHECK-NEXT: [[_3_JT1:%.*]] = phi i32 [ [[DOTSI_UNFOLD_PHI2_JT1]], [[SEL_SI_UNFOLD_FALSE_JT1]] ]
+; CHECK-NEXT: br label [[BB8]]
; CHECK: BB7.jt0:
-; CHECK-NEXT: [[D_PROMOTED4_JT0:%.*]] = phi i16 [ 0, [[BB1]] ], [ 1, [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0]] ]
-; CHECK-NEXT: [[_3_JT0:%.*]] = phi i32 [ 0, [[BB1]] ], [ [[DOTSI_UNFOLD_PHI_JT0]], [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0]] ]
+; CHECK-NEXT: [[D_PROMOTED4_JT0:%.*]] = phi i16 [ 0, [[BB1]] ], [ 1, [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0]] ], [ 1, [[BB7]] ]
+; CHECK-NEXT: [[_3_JT0:%.*]] = phi i32 [ 0, [[BB1]] ], [ [[DOTSI_UNFOLD_PHI_JT0]], [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0]] ], [ [[DOTSI_UNFOLD_PHI1]], [[BB7]] ]
; CHECK-NEXT: br label [[BB1]]
; CHECK: BB1.backedge:
; CHECK-NEXT: br label [[BB1]]
@@ -382,19 +391,27 @@ define void @pr106083_select_dead_uses(i1 %cmp1, i1 %not, ptr %p) {
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ 0, [[BB1]] ]
; CHECK-NEXT: br label [[SELECT_UNFOLD_JT0]]
; CHECK: spec.select.si.unfold.true:
+; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[SELECT_UNFOLD1]], label [[SPEC_SELECT_SI_UNFOLD_FALSE_JT1:%.*]]
+; CHECK: spec.select.si.unfold.true.jt0:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI1:%.*]] = phi i32 [ 0, [[BB1]] ]
-; CHECK-NEXT: br i1 [[CMP1:%.*]], label [[SELECT_UNFOLD1]], label [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]]
+; CHECK-NEXT: br i1 [[CMP1]], label [[SELECT_UNFOLD_JT0]], label [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]]
; CHECK: spec.select.si.unfold.false:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI2:%.*]] = phi i32 [ 1, [[SELECT_UNFOLD]] ]
; CHECK-NEXT: br label [[SELECT_UNFOLD1]]
+; CHECK: spec.select.si.unfold.false.jt1:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI2_JT1:%.*]] = phi i32 [ 1, [[SPEC_SELECT_SI_UNFOLD_TRUE:%.*]] ]
+; CHECK-NEXT: br label [[SELECT_UNFOLD_JT1:%.*]]
; CHECK: select.unfold:
-; CHECK-NEXT: [[_2:%.*]] = phi i32 [ poison, [[SPEC_SELECT7_SI_UNFOLD_FALSE:%.*]] ], [ [[DOTSI_UNFOLD_PHI1]], [[SELECT_UNFOLD]] ], [ [[DOTSI_UNFOLD_PHI2]], [[SPEC_SELECT_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: [[_2:%.*]] = phi i32 [ poison, [[SPEC_SELECT7_SI_UNFOLD_FALSE:%.*]] ], [ poison, [[SPEC_SELECT_SI_UNFOLD_TRUE]] ], [ [[DOTSI_UNFOLD_PHI2]], [[SPEC_SELECT_SI_UNFOLD_FALSE]] ]
; CHECK-NEXT: switch i32 [[_2]], label [[BB2:%.*]] [
; CHECK-NEXT: i32 0, label [[DOTPREHEADER_PREHEADER:%.*]]
; CHECK-NEXT: i32 1, label [[DOTLOOPEXIT6]]
; CHECK-NEXT: ]
+; CHECK: select.unfold.jt1:
+; CHECK-NEXT: [[_2_JT1:%.*]] = phi i32 [ [[DOTSI_UNFOLD_PHI2_JT1]], [[SPEC_SELECT_SI_UNFOLD_FALSE_JT1]] ]
+; CHECK-NEXT: br label [[DOTLOOPEXIT6]]
; CHECK: select.unfold.jt0:
-; CHECK-NEXT: [[_2_JT0:%.*]] = phi i32 [ 0, [[DOTLOOPEXIT6]] ], [ [[DOTSI_UNFOLD_PHI_JT0]], [[SPEC_SELECT7_SI_UNFOLD_FALSE_JT0]] ]
+; CHECK-NEXT: [[_2_JT0:%.*]] = phi i32 [ 0, [[DOTLOOPEXIT6]] ], [ [[DOTSI_UNFOLD_PHI_JT0]], [[SPEC_SELECT7_SI_UNFOLD_FALSE_JT0]] ], [ [[DOTSI_UNFOLD_PHI1]], [[SELECT_UNFOLD]] ]
; CHECK-NEXT: br label [[DOTPREHEADER_PREHEADER]]
; CHECK: .preheader.preheader:
; CHECK-NEXT: ret void
diff --git a/llvm/test/Transforms/DFAJumpThreading/dfa-unfold-select.ll b/llvm/test/Transforms/DFAJumpThreading/dfa-unfold-select.ll
index 7fc70e838f2fd..663f459e23084 100644
--- a/llvm/test/Transforms/DFAJumpThreading/dfa-unfold-select.ll
+++ b/llvm/test/Transforms/DFAJumpThreading/dfa-unfold-select.ll
@@ -473,39 +473,53 @@ define i16 @pr160250() {
; CHECK: if.else:
; CHECK-NEXT: br i1 false, label [[DOT6_SI_UNFOLD_TRUE:%.*]], label [[DOT5_SI_UNFOLD_TRUE:%.*]]
; CHECK: .5.si.unfold.true:
+; CHECK-NEXT: br i1 false, label [[SPEC_SELECT1_SI_UNFOLD_TRUE1:%.*]], label [[DOT5_SI_UNFOLD_FALSE_JT0:%.*]]
+; CHECK: .5.si.unfold.true.jt0:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI1:%.*]] = phi i32 [ 0, [[IF_ELSE]] ]
; CHECK-NEXT: br i1 false, label [[SPEC_SELECT1_SI_UNFOLD_TRUE:%.*]], label [[DOT5_SI_UNFOLD_FALSE:%.*]]
; CHECK: .5.si.unfold.false:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI2:%.*]] = phi i32 [ 0, [[DOT5_SI_UNFOLD_TRUE]] ]
+; CHECK-NEXT: br label [[SPEC_SELECT1_SI_UNFOLD_TRUE1]]
+; CHECK: .5.si.unfold.false.jt0:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI2_JT0:%.*]] = phi i32 [ 0, [[DOT5_SI_UNFOLD_TRUE1:%.*]] ]
; CHECK-NEXT: br label [[SPEC_SELECT1_SI_UNFOLD_TRUE]]
; CHECK: spec.select1.si.unfold.true:
-; CHECK-NEXT: [[DOT5_SI_UNFOLD_PHI:%.*]] = phi i32 [ [[DOTSI_UNFOLD_PHI1]], [[DOT5_SI_UNFOLD_TRUE]] ], [ [[DOTSI_UNFOLD_PHI2]], [[DOT5_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: [[DOT5_SI_UNFOLD_PHI:%.*]] = phi i32 [ poison, [[DOT5_SI_UNFOLD_TRUE1]] ], [ [[DOTSI_UNFOLD_PHI2]], [[DOT5_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: br i1 false, label [[SPEC_SELECT_SI_UNFOLD_FALSE1:%.*]], label [[SPEC_SELECT1_SI_UNFOLD_FALSE_JT1:%.*]]
+; CHECK: spec.select1.si.unfold.true.jt0:
+; CHECK-NEXT: [[DOT5_SI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ [[DOTSI_UNFOLD_PHI1]], [[DOT5_SI_UNFOLD_TRUE]] ], [ [[DOTSI_UNFOLD_PHI2_JT0]], [[DOT5_SI_UNFOLD_FALSE_JT0]] ]
; CHECK-NEXT: br i1 false, label [[SPEC_SELECT_SI_UNFOLD_FALSE:%.*]], label [[SPEC_SELECT1_SI_UNFOLD_FALSE_JT0:%.*]]
; CHECK: spec.select1.si.unfold.false:
-; CHECK-NEXT: br label [[SPEC_SELECT_SI_UNFOLD_FALSE]]
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI:%.*]] = phi i32 [ 0, [[SPEC_SELECT1_SI_UNFOLD_TRUE]] ]
+; CHECK-NEXT: br label [[SPEC_SELECT_SI_UNFOLD_FALSE1]]
; CHECK: spec.select1.si.unfold.false.jt0:
-; CHECK-NEXT: [[DOTSI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ 0, [[SPEC_SELECT1_SI_UNFOLD_TRUE]] ]
-; CHECK-NEXT: br label [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0:%.*]]
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ 0, [[SPEC_SELECT1_SI_UNFOLD_TRUE1]] ]
+; CHECK-NEXT: br label [[SPEC_SELECT_SI_UNFOLD_FALSE]]
; CHECK: spec.select.si.unfold.false:
-; CHECK-NEXT: [[SPEC_SELECT1_SI_UNFOLD_PHI:%.*]] = phi i32 [ [[DOT5_SI_UNFOLD_PHI]], [[SPEC_SELECT1_SI_UNFOLD_TRUE]] ], [ poison, [[SPEC_SELECT1_SI_UNFOLD_FALSE:%.*]] ]
+; CHECK-NEXT: [[SPEC_SELECT1_SI_UNFOLD_PHI:%.*]] = phi i32 [ [[DOT5_SI_UNFOLD_PHI]], [[SPEC_SELECT1_SI_UNFOLD_TRUE1]] ], [ [[DOTSI_UNFOLD_PHI]], [[SPEC_SELECT1_SI_UNFOLD_FALSE_JT0]] ]
; CHECK-NEXT: br label [[CLEANUP87:%.*]]
; CHECK: spec.select.si.unfold.false.jt0:
-; CHECK-NEXT: [[SPEC_SELECT1_SI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ [[DOTSI_UNFOLD_PHI_JT0]], [[SPEC_SELECT1_SI_UNFOLD_FALSE_JT0]] ]
+; CHECK-NEXT: [[SPEC_SELECT1_SI_UNFOLD_PHI_JT0:%.*]] = phi i32 [ [[DOT5_SI_UNFOLD_PHI_JT0]], [[SPEC_SELECT1_SI_UNFOLD_TRUE]] ], [ [[DOTSI_UNFOLD_PHI_JT0]], [[SPEC_SELECT1_SI_UNFOLD_FALSE_JT1]] ]
; CHECK-NEXT: br label [[CLEANUP87_JT0]]
; CHECK: .6.si.unfold.true:
+; CHECK-NEXT: br i1 false, label [[CLEANUP87]], label [[DOT6_SI_UNFOLD_FALSE_JT0:%.*]]
+; CHECK: .6.si.unfold.true.jt0:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI3:%.*]] = phi i32 [ 0, [[IF_ELSE]] ]
-; CHECK-NEXT: br i1 false, label [[CLEANUP87]], label [[DOT6_SI_UNFOLD_FALSE:%.*]]
+; CHECK-NEXT: br i1 false, label [[CLEANUP87_JT0]], label [[DOT6_SI_UNFOLD_FALSE:%.*]]
; CHECK: .6.si.unfold.false:
; CHECK-NEXT: [[DOTSI_UNFOLD_PHI4:%.*]] = phi i32 [ 0, [[DOT6_SI_UNFOLD_TRUE]] ]
; CHECK-NEXT: br label [[CLEANUP87]]
+; CHECK: .6.si.unfold.false.jt0:
+; CHECK-NEXT: [[DOTSI_UNFOLD_PHI4_JT0:%.*]] = phi i32 [ 0, [[DOT6_SI_UNFOLD_TRUE1:%.*]] ]
+; CHECK-NEXT: br label [[CLEANUP87_JT0]]
; CHECK: cleanup87:
-; CHECK-NEXT: [[CLEANUP_DEST_SLOT_3:%.*]] = phi i32 [ [[SPEC_SELECT1_SI_UNFOLD_PHI]], [[SPEC_SELECT_SI_UNFOLD_FALSE]] ], [ [[DOTSI_UNFOLD_PHI3]], [[DOT6_SI_UNFOLD_TRUE]] ], [ [[DOTSI_UNFOLD_PHI4]], [[DOT6_SI_UNFOLD_FALSE]] ]
+; CHECK-NEXT: [[CLEANUP_DEST_SLOT_3:%.*]] = phi i32 [ [[SPEC_SELECT1_SI_UNFOLD_PHI]], [[SPEC_SELECT_SI_UNFOLD_FALSE1]] ], [ poison, [[DOT6_SI_UNFOLD_TRUE1]] ], [ [[DOTSI_UNFOLD_PHI4]], [[DOT6_SI_UNFOLD_FALSE]] ]
; CHECK-NEXT: switch i32 [[CLEANUP_DEST_SLOT_3]], label [[FOR_COND48_BACKEDGE:%.*]] [
; CHECK-NEXT: i32 0, label [[FOR_COND48_BACKEDGE]]
; CHECK-NEXT: i32 1, label [[FOR_COND48_BACKEDGE]]
; CHECK-NEXT: ]
; CHECK: cleanup87.jt0:
-; CHECK-NEXT: [[CLEANUP_DEST_SLOT_3_JT0:%.*]] = phi i32 [ 0, [[FOR_COND48]] ], [ [[SPEC_SELECT1_SI_UNFOLD_PHI_JT0]], [[SPEC_SELECT_SI_UNFOLD_FALSE_JT0]] ]
+; CHECK-NEXT: [[CLEANUP_DEST_SLOT_3_JT0:%.*]] = phi i32 [ 0, [[FOR_COND48]] ], [ [[SPEC_SELECT1_SI_UNFOLD_PHI_JT0]], [[SPEC_SELECT_SI_UNFOLD_FALSE]] ], [ [[DOTSI_UNFOLD_PHI3]], [[DOT6_SI_UNFOLD_TRUE]] ], [ [[DOTSI_UNFOLD_PHI4_JT0]], [[DOT6_SI_UNFOLD_FALSE_JT0]] ]
; CHECK-NEXT: br label [[FOR_COND48_BACKEDGE]]
; CHECK: for.cond48.backedge:
; CHECK-NEXT: br label [[FOR_COND48]]
>From 5559c094978ebc7bd21ad9626e01efab606a8bdb Mon Sep 17 00:00:00 2001
From: XChy <xxs_chy at outlook.com>
Date: Wed, 1 Oct 2025 16:54:10 +0800
Subject: [PATCH 3/3] resolve comment
---
llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp b/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
index 1da312c5a85ff..e9a3e983bc1e2 100644
--- a/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
@@ -192,7 +192,7 @@ void unfold(DomTreeUpdater *DTU, LoopInfo *LI, SelectInstToUnfold SIToUnfold,
PHINode *SIUse = SIToUnfold.getUse();
assert(SI->hasOneUse());
// The select may come indirectly, instead of from where it is defined.
- BasicBlock *StartBlock = SIUse->getIncomingBlock(SI->user_begin().getUse());
+ BasicBlock *StartBlock = SIUse->getIncomingBlock(*SI->use_begin());
BranchInst *StartBlockTerm =
dyn_cast<BranchInst>(StartBlock->getTerminator());
assert(StartBlockTerm);
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