[SimplifyCFG] Fold pairs of entries in multiple-entry phi

[XChy]

Resolves #73380.
In this PR, I've done:

• Add tests for [SimplifyCFG] Missed optimization: Fail to merge part of phi into one select #73380.
• Refactor logic of FoldTwoEntryPHINode in SimplifyCFG, so that we can easily fold such pattern based on both dominant and merge point of the if-region.
• Add logic for folding one of entry pair in multiple-entry phi based on both dominant and merge point.

[llvmbot]

@llvm/pr-subscribers-backend-arm

@llvm/pr-subscribers-llvm-transforms

Author: XChy (XChy)

Changes

Resolves #73380.
In this PR, I've done:

• Add tests for #73380.
• Refactor logic of FoldTwoEntryPHINode in SimplifyCFG, so that we can easily fold such pattern based on both dominant and merge point of the if-region.
• Add logic for folding one of entry pair in multiple-entry phi based on both dominant.

Somehow this PR causes some regressions for doing such fold in incorrect order, I don't know where to place it now and it may take some time to find the place to do fold.

---

Patch is 46.06 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/73674.diff

11 Files Affected:

• (modified) llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h (+13-1)
• (modified) llvm/lib/Transforms/Utils/BasicBlockUtils.cpp (+42-1)
• (modified) llvm/lib/Transforms/Utils/FlattenCFG.cpp (+2-2)
• (modified) llvm/lib/Transforms/Utils/SimplifyCFG.cpp (+79-41)
• (modified) llvm/test/Transforms/SimplifyCFG/PhiEliminate2.ll (+18-15)
• (modified) llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll (+4-6)
• (modified) llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll (+13-12)
• (modified) llvm/test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll (+65-74)
• (added) llvm/test/Transforms/SimplifyCFG/fold-multiple-entry-phi.ll (+212)
• (modified) llvm/test/Transforms/SimplifyCFG/no-md-sink.ll (+4-3)
• (modified) llvm/test/Transforms/SimplifyCFG/opaque-ptr.ll (+4-2)

diff --git a/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h b/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h index e6dde450b7df9c8..998acbe9ab75da7 100644 --- a/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h +++ b/llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h @@ -595,9 +595,21 @@ void SplitBlockAndInsertForEachLane( /// /// This does no checking to see if the true/false blocks have large or unsavory /// instructions in them. -BranchInst *GetIfCondition(BasicBlock *BB, BasicBlock *&IfTrue, +BranchInst *GetIfConditionFromMergePoint(BasicBlock *BB, BasicBlock *&IfTrue, BasicBlock *&IfFalse); +/// Check whether BB is the dominant point of a if-region. +/// If so, return the merge point of the if-region. Also, return by references +/// the block that will be entered from if the condition is true, and the block +/// that will be entered if the condition is false. +/// +/// This does no checking to see if the true/false blocks have large or unsavory +/// instructions in them. +/// +/// NOTE: we assume that the terminator of DomBB is a conditional branch instruction.  +BasicBlock *GetIfConditionFromDom(BasicBlock *DomBB, BasicBlock *&IfTrue, + BasicBlock *&IfFalse); + // Split critical edges where the source of the edge is an indirectbr // instruction. This isn't always possible, but we can handle some easy cases. // This is useful because MI is unable to split such critical edges, diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp index 168998fbee114ab..d43a5f72846f72c 100644 --- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp +++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp @@ -1727,7 +1727,7 @@ void llvm::SplitBlockAndInsertForEachLane( } } -BranchInst *llvm::GetIfCondition(BasicBlock *BB, BasicBlock *&IfTrue, +BranchInst *llvm::GetIfConditionFromMergePoint(BasicBlock *BB, BasicBlock *&IfTrue, BasicBlock *&IfFalse) { PHINode *SomePHI = dyn_cast<PHINode>(BB->begin()); BasicBlock *Pred1 = nullptr; @@ -1819,6 +1819,47 @@ BranchInst *llvm::GetIfCondition(BasicBlock *BB, BasicBlock *&IfTrue, return BI; } +BasicBlock *llvm::GetIfConditionFromDom(BasicBlock *DomBB, BasicBlock *&IfTrue, + BasicBlock *&IfFalse) { + BranchInst* BI = cast<BranchInst>(DomBB->getTerminator()); + BasicBlock *Succ1 = BI->getSuccessor(0); + BasicBlock *Succ2 = BI->getSuccessor(1); + + if (!Succ1->getSinglePredecessor() || !Succ2->getSinglePredecessor() || + Succ1 == Succ2 || Succ1 == DomBB || Succ2 == DomBB) + return nullptr; + + // We can only handle branches. Other control flow will be lowered to + // branches if possible anyway. + BranchInst *Succ1Br = dyn_cast<BranchInst>(Succ1->getTerminator()); + BranchInst *Succ2Br = dyn_cast<BranchInst>(Succ2->getTerminator()); + if (!Succ1Br || !Succ2Br) + return nullptr; + + if (Succ1->getSingleSuccessor() == Succ2) { + IfTrue = Succ1; + IfFalse = DomBB; + return Succ2; + } + + if (Succ2->getSingleSuccessor() == Succ1) { + IfTrue = DomBB; + IfFalse = Succ2; + return Succ1; + } + + auto *CommonDest = Succ1->getSingleSuccessor(); + if (CommonDest && CommonDest != DomBB && + CommonDest == Succ2->getSingleSuccessor()) { + IfTrue = Succ1; + IfFalse = Succ2; + return CommonDest; + } + + // There may be other cases, but we just handle the trivial ones now. + return nullptr; +} + // After creating a control flow hub, the operands of PHINodes in an outgoing // block Out no longer match the predecessors of that block. Predecessors of Out // that are incoming blocks to the hub are now replaced by just one edge from diff --git a/llvm/lib/Transforms/Utils/FlattenCFG.cpp b/llvm/lib/Transforms/Utils/FlattenCFG.cpp index 1925b91c4da7ec1..4480202bae8e7db 100644 --- a/llvm/lib/Transforms/Utils/FlattenCFG.cpp +++ b/llvm/lib/Transforms/Utils/FlattenCFG.cpp @@ -408,7 +408,7 @@ bool FlattenCFGOpt::CompareIfRegionBlock(BasicBlock *Block1, BasicBlock *Block2, /// approach goes for the opposite case. bool FlattenCFGOpt::MergeIfRegion(BasicBlock *BB, IRBuilder<> &Builder) { BasicBlock *IfTrue2, *IfFalse2; - BranchInst *DomBI2 = GetIfCondition(BB, IfTrue2, IfFalse2); + BranchInst *DomBI2 = GetIfConditionFromMergePoint(BB, IfTrue2, IfFalse2); if (!DomBI2) return false; Instruction *CInst2 = dyn_cast<Instruction>(DomBI2->getCondition()); @@ -420,7 +420,7 @@ bool FlattenCFGOpt::MergeIfRegion(BasicBlock *BB, IRBuilder<> &Builder) { return false; BasicBlock *IfTrue1, *IfFalse1; - BranchInst *DomBI1 = GetIfCondition(SecondEntryBlock, IfTrue1, IfFalse1); + BranchInst *DomBI1 = GetIfConditionFromMergePoint(SecondEntryBlock, IfTrue1, IfFalse1); if (!DomBI1) return false; Instruction *CInst1 = dyn_cast<Instruction>(DomBI1->getCondition()); diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index c09cf9c2325c405..cc6badab9d19712 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -3403,35 +3403,37 @@ static bool FoldCondBranchOnValueKnownInPredecessor(BranchInst *BI, return EverChanged; } -/// Given a BB that starts with the specified two-entry PHI node, -/// see if we can eliminate it. -static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI, - DomTreeUpdater *DTU, const DataLayout &DL) { - // Ok, this is a two entry PHI node. Check to see if this is a simple "if - // statement", which has a very simple dominance structure. Basically, we - // are trying to find the condition that is being branched on, which - // subsequently causes this merge to happen. We really want control - // dependence information for this check, but simplifycfg can't keep it up - // to date, and this catches most of the cases we care about anyway. - BasicBlock *BB = PN->getParent(); - - BasicBlock *IfTrue, *IfFalse; - BranchInst *DomBI = GetIfCondition(BB, IfTrue, IfFalse); - if (!DomBI) +// Fold phis in BB based on if-else information. +static bool FoldPHIOfIfRegion(BasicBlock *BB, BasicBlock *DomBlock, + BasicBlock *IfTrue, BasicBlock *IfFalse, + const TargetTransformInfo &TTI, + DomTreeUpdater *DTU, const DataLayout &DL) { + assert(isa<BranchInst>(DomBlock->getTerminator())); + + if (BB->phis().empty()) return false; + + PHINode *PN = &*BB->phis().begin(); + + BranchInst *DomBI = cast<BranchInst>(DomBlock->getTerminator()); Value *IfCond = DomBI->getCondition(); // Don't bother if the branch will be constant folded trivially. if (isa<ConstantInt>(IfCond)) return false; - BasicBlock *DomBlock = DomBI->getParent(); - SmallVector<BasicBlock *, 2> IfBlocks; + // Track BBs that jumps into phi unconditionally, to handle the cases where + // one of {IfTrue, IfFalse} is DomBlock. + SmallVector<BasicBlock *, 2> UncondEnterBlocks; llvm::copy_if( - PN->blocks(), std::back_inserter(IfBlocks), [](BasicBlock *IfBlock) { + SmallVector<BasicBlock *, 2>{IfTrue, IfFalse}, + std::back_inserter(UncondEnterBlocks), [](BasicBlock *IfBlock) { return cast<BranchInst>(IfBlock->getTerminator())->isUnconditional(); }); - assert((IfBlocks.size() == 1 || IfBlocks.size() == 2) && - "Will have either one or two blocks to speculate."); + + // NOTE: Keep the order of BBs the same as the order in phi. + llvm::sort(UncondEnterBlocks, [PN](BasicBlock *B1, BasicBlock *B2) { + return PN->getBasicBlockIndex(B1) < PN->getBasicBlockIndex(B2); + }); // If the branch is non-unpredictable, see if we either predictably jump to // the merge bb (if we have only a single 'then' block), or if we predictably @@ -3446,7 +3448,7 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI, BranchProbability::getBranchProbability(TWeight, TWeight + FWeight); BranchProbability Likely = TTI.getPredictableBranchThreshold(); BranchProbability BIFalseProb = BITrueProb.getCompl(); - if (IfBlocks.size() == 1) { + if (UncondEnterBlocks.size() == 1) { BranchProbability BIBBProb = DomBI->getSuccessor(0) == BB ? BITrueProb : BIFalseProb; if (BIBBProb >= Likely) @@ -3492,10 +3494,10 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI, continue; } - if (!dominatesMergePoint(PN->getIncomingValue(0), BB, AggressiveInsts, - Cost, Budget, TTI) || - !dominatesMergePoint(PN->getIncomingValue(1), BB, AggressiveInsts, - Cost, Budget, TTI)) + if (!dominatesMergePoint(PN->getIncomingValueForBlock(IfTrue), BB, + AggressiveInsts, Cost, Budget, TTI) || + !dominatesMergePoint(PN->getIncomingValueForBlock(IfFalse), BB, + AggressiveInsts, Cost, Budget, TTI)) return Changed; } @@ -3525,18 +3527,21 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI, m_CombineOr(m_Select(m_Value(), m_ImmConstant(), m_Value()), m_Select(m_Value(), m_Value(), m_ImmConstant())))); }; + + Value *TrueVal = PN->getIncomingValueForBlock(IfTrue); + Value *FalseVal = PN->getIncomingValueForBlock(IfFalse); + if (PN->getType()->isIntegerTy(1) && - (IsBinOpOrAnd(PN->getIncomingValue(0)) || - IsBinOpOrAnd(PN->getIncomingValue(1)) || IsBinOpOrAnd(IfCond)) && - !CanHoistNotFromBothValues(PN->getIncomingValue(0), - PN->getIncomingValue(1))) + (IsBinOpOrAnd(TrueVal) || IsBinOpOrAnd(FalseVal) || + IsBinOpOrAnd(IfCond)) && + !CanHoistNotFromBothValues(TrueVal, FalseVal)) return Changed; // If all PHI nodes are promotable, check to make sure that all instructions // in the predecessor blocks can be promoted as well. If not, we won't be able // to get rid of the control flow, so it's not worth promoting to select // instructions. - for (BasicBlock *IfBlock : IfBlocks) + for (BasicBlock *IfBlock : UncondEnterBlocks) for (BasicBlock::iterator I = IfBlock->begin(); !I->isTerminator(); ++I) if (!AggressiveInsts.count(&*I) && !I->isDebugOrPseudoInst()) { // This is not an aggressive instruction that we can promote. @@ -3546,7 +3551,7 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI, } // If either of the blocks has it's address taken, we can't do this fold. - if (any_of(IfBlocks, + if (any_of(UncondEnterBlocks, [](BasicBlock *IfBlock) { return IfBlock->hasAddressTaken(); })) return Changed; @@ -3559,27 +3564,31 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI, // Move all 'aggressive' instructions, which are defined in the // conditional parts of the if's up to the dominating block. - for (BasicBlock *IfBlock : IfBlocks) - hoistAllInstructionsInto(DomBlock, DomBI, IfBlock); + for (BasicBlock *IfBlock : UncondEnterBlocks) + hoistAllInstructionsInto(DomBlock, DomBI, IfBlock); IRBuilder<NoFolder> Builder(DomBI); // Propagate fast-math-flags from phi nodes to replacement selects. IRBuilder<>::FastMathFlagGuard FMFGuard(Builder); - while (PHINode *PN = dyn_cast<PHINode>(BB->begin())) { + for (PHINode &PN : make_early_inc_range(BB->phis())) { if (isa<FPMathOperator>(PN)) - Builder.setFastMathFlags(PN->getFastMathFlags()); + Builder.setFastMathFlags(PN.getFastMathFlags()); // Change the PHI node into a select instruction. - Value *TrueVal = PN->getIncomingValueForBlock(IfTrue); - Value *FalseVal = PN->getIncomingValueForBlock(IfFalse); + Value *TrueVal = PN.getIncomingValueForBlock(IfTrue); + Value *FalseVal = PN.getIncomingValueForBlock(IfFalse); Value *Sel = Builder.CreateSelect(IfCond, TrueVal, FalseVal, "", DomBI); - PN->replaceAllUsesWith(Sel); - Sel->takeName(PN); - PN->eraseFromParent(); + if (PN.getNumIncomingValues() == 2) { + PN.replaceAllUsesWith(Sel); + Sel->takeName(&PN); + PN.eraseFromParent(); + } else { + PN.addIncoming(Sel, DomBlock); + } } - // At this point, all IfBlocks are empty, so our if statement + // At this point, all UncondEnterBlocks are empty, so our if statement // has been flattened. Change DomBlock to jump directly to our new block to // avoid other simplifycfg's kicking in on the diamond. Builder.CreateBr(BB); @@ -3598,6 +3607,25 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI, return true; } +/// Given a BB that starts with the specified two-entry PHI node, +/// see if we can eliminate it. +static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI, + DomTreeUpdater *DTU, const DataLayout &DL) { + // Ok, this is a two entry PHI node. Check to see if this is a simple "if + // statement", which has a very simple dominance structure. Basically, we + // are trying to find the condition that is being branched on, which + // subsequently causes this merge to happen. We really want control + // dependence information for this check, but simplifycfg can't keep it up + // to date, and this catches most of the cases we care about anyway. + BasicBlock *BB = PN->getParent(); + BasicBlock *IfTrue, *IfFalse; + BranchInst *DomBI = GetIfConditionFromMergePoint(BB, IfTrue, IfFalse); + if (!DomBI) + return false; + BasicBlock *DomBlock = DomBI->getParent(); + return FoldPHIOfIfRegion(BB, DomBlock, IfTrue, IfFalse, TTI, DTU, DL); +} + static Value *createLogicalOp(IRBuilderBase &Builder, Instruction::BinaryOps Opc, Value *LHS, Value *RHS, const Twine &Name = "") { @@ -7315,6 +7343,7 @@ bool SimplifyCFGOpt::simplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) { if (HoistCommon && hoistCommonCodeFromSuccessors( BI->getParent(), !Options.HoistCommonInsts)) return requestResimplify(); + } else { // If Successor #1 has multiple preds, we may be able to conditionally // execute Successor #0 if it branches to Successor #1. @@ -7355,6 +7384,15 @@ bool SimplifyCFGOpt::simplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) { if (mergeConditionalStores(PBI, BI, DTU, DL, TTI)) return requestResimplify(); + // Fold the merge-point phi of if-region. + BasicBlock *IfTrue; + BasicBlock *IfFalse; + if (Options.SpeculateBlocks && + !BB->getParent()->hasFnAttribute(Attribute::OptForFuzzing)) + if (BasicBlock *CommonDest = GetIfConditionFromDom(BB, IfTrue, IfFalse)) + if (FoldPHIOfIfRegion(CommonDest, BB, IfTrue, IfFalse, TTI, DTU, DL)) + return requestResimplify(); + return false; } diff --git a/llvm/test/Transforms/SimplifyCFG/PhiEliminate2.ll b/llvm/test/Transforms/SimplifyCFG/PhiEliminate2.ll index 3b7cbcf1534ae42..ea2f2f1491c5289 100644 --- a/llvm/test/Transforms/SimplifyCFG/PhiEliminate2.ll +++ b/llvm/test/Transforms/SimplifyCFG/PhiEliminate2.ll @@ -1,29 +1,32 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3 ; RUN: opt < %s -passes=simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s ; Use a select to make this a single BB. ; Also, make sure the profile metadata is propagated to the select (PR26636). define i32 @FoldTwoEntryPHINode(i1 %C, i32 %V1, i32 %V2, i16 %V3) { +; CHECK-LABEL: define i32 @FoldTwoEntryPHINode( +; CHECK-SAME: i1 [[C:%.*]], i32 [[V1:%.*]], i32 [[V2:%.*]], i16 [[V3:%.*]]) { +; CHECK-NEXT: entry: +; CHECK-NEXT: [[V5:%.*]] = sext i16 [[V3]] to i32 +; CHECK-NEXT: [[V4:%.*]] = or i32 [[V2]], [[V1]] +; CHECK-NEXT: [[V6:%.*]] = select i1 [[C]], i32 [[V4]], i32 [[V5]], !prof [[PROF0:![0-9]+]], !unpredictable !1 +; CHECK-NEXT: [[TMP0:%.*]] = call i32 @FoldTwoEntryPHINode(i1 false, i32 0, i32 0, i16 0) +; CHECK-NEXT: ret i32 [[V1]] +; entry: - br i1 %C, label %then, label %else, !prof !0, !unpredictable !1 + br i1 %C, label %then, label %else, !prof !0, !unpredictable !1 then: - %V4 = or i32 %V2, %V1 - br label %Cont + %V4 = or i32 %V2, %V1 + br label %Cont else: - %V5 = sext i16 %V3 to i32 - br label %Cont + %V5 = sext i16 %V3 to i32 + br label %Cont Cont: - %V6 = phi i32 [ %V5, %else ], [ %V4, %then ] - call i32 @FoldTwoEntryPHINode( i1 false, i32 0, i32 0, i16 0 ) - ret i32 %V1 + %V6 = phi i32 [ %V5, %else ], [ %V4, %then ] + call i32 @FoldTwoEntryPHINode( i1 false, i32 0, i32 0, i16 0 ) + ret i32 %V1 -; CHECK-LABEL: @FoldTwoEntryPHINode( -; CHECK-NEXT: entry: -; CHECK-NEXT: %V5 = sext i16 %V3 to i32 -; CHECK-NEXT: %V4 = or i32 %V2, %V1 -; CHECK-NEXT: %V6 = select i1 %C, i32 %V4, i32 %V5, !prof !0, !unpredictable !1 -; CHECK-NEXT: %0 = call i32 @FoldTwoEntryPHINode(i1 false, i32 0, i32 0, i16 0) -; CHECK-NEXT: ret i32 %V1 } !0 = !{!"branch_weights", i32 3, i32 5} diff --git a/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll b/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll index 5ba43c055f9be12..2710f8426eeab96 100644 --- a/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll +++ b/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll @@ -64,9 +64,8 @@ T: define void @test5(i1 %cond, ptr %ptr) { ; CHECK-LABEL: @test5( ; CHECK-NEXT: entry: -; CHECK-NEXT: [[TMP0:%.*]] = xor i1 [[COND:%.*]], true -; CHECK-NEXT: call void @llvm.assume(i1 [[TMP0]]) -; CHECK-NEXT: store i8 2, ptr [[PTR:%.*]], align 8 +; CHECK-NEXT: [[PTR_2:%.*]] = select i1 [[COND:%.*]], ptr null, ptr [[PTR:%.*]] +; CHECK-NEXT: store i8 2, ptr [[PTR_2]], align 8 ; CHECK-NEXT: ret void ; entry: @@ -93,11 +92,10 @@ declare i1 @llvm.type.test(ptr, metadata) nounwind readnone define void @test5_type_test_assume(i1 %cond, ptr %ptr, ptr %vtable) { ; CHECK-LABEL: @test5_type_test_assume( ; CHECK-NEXT: entry: -; CHECK-NEXT: [[TMP0:%.*]] = xor i1 [[COND:%.*]], true -; CHECK-NEXT: call void @llvm.assume(i1 [[TMP0]]) +; CHECK-NEXT: [[PTR_2:%.*]] = select i1 [[COND:%.*]], ptr null, ptr [[PTR:%.*]] ; CHECK-NEXT: [[P:%.*]] = call i1 @llvm.type.test(ptr [[VTABLE:%.*]], metadata !"foo") ; CHECK-NEXT: tail call void @llvm.assume(i1 [[P]]) -; CHECK-NEXT: store i8 2, ptr [[PTR:%.*]], align 8 +; CHECK-NEXT: store i8 2, ptr [[PTR_2]], align 8 ; CHECK-NEXT: ret void ; entry: diff --git a/llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll b/llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll index 26107965a1a8b6d..b54b55725fd8425 100644 --- a/llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll +++ b/llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll @@ -693,8 +693,8 @@ define zeroext i1 @test17(i32 %flag, i32 %blksA, i32 %blksB, i32 %nblks) { ; CHECK-LABEL: @test17( ; CHECK-NEXT: entry: ; CHECK-NEXT: switch i32 [[FLAG:%.*]], label [[IF_END:%.*]] [ -; CHECK-NEXT: i32 0, label [[IF_THEN:%.*]] -; CHECK-NEXT: i32 1, label [[IF_THEN2:%.*]] +; CHECK-NEXT: i32 0, label [[IF_THEN:%.*]] +; CHECK-NEXT: i32 1, label [[IF_THEN2:%.*]] ; CHECK-NEXT: ] ; CHECK: if.then: ; CHECK-NEXT: [[CMP:%.*]] = icmp uge i32 [[BLKSA:%.*]], [[NBLKS:%.*]] @@ -744,8 +744,8 @@ define zeroext i1 @test18(i32 %flag, i32 %blksA, i32 %blksB, i32 %nblks) { ; CHECK-LABEL: @test18( ; CHECK-NEXT: entry: ; CHECK-NEXT: switch i32 [[FLAG:%.*]], label [[IF_THEN3:%.*]] [ -; CHECK-NEXT: i32 0, label [[IF_THEN:%.*]] -; CHECK-NEXT: i32 1, label [[IF_THEN2:%.*]] +; CHECK-NEXT: i32 0, label [[IF_THEN:%.*]] +; CHECK-NEXT: i32 1, label [[IF_THEN2:%.*]] ; CHECK-NEXT: ] ; CHECK: if.then: ; CHECK-NEXT: [[CMP:%.*]] = icmp uge i32 [[BLKSA:%.*]], [[NBLKS:%.*]] @@ -1257,8 +1257,9 @@ merge: define i32 @test_insertvalue(i1 zeroext %flag, %TP %P) { ; CHECK-LABEL: @test_insertvalue( ; CHECK-NEXT: entry: -; CHECK-NEXT: [[DOT:%.*]] = select i1 [[FLAG:%.*]], i32 0, i32 1 -; CHECK-NEXT: [[I2:%.*]] = insertvalue [[TP:%.*]] [[P:%.*]], i32 [[DOT]], 0 +; CHECK-NEXT: [[I1:%.*]] = insertvalue [[TP... [truncated] 

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[XChy]

TODO:
Make other folds on merge-point phi done ahead of this fold on dominant basic block.

[XChy]

Now this patch calls simplifyOnce(MergePoint) early to keep original optimization order.

[XChy]

ping.

[TiborGY]

@XChy Do you still intend to get this PR merged?

[XChy]

@XChy Do you still intend to get this PR merged?

@TiborGY I am not working on this PR now. If you are interested in this problem, feel free to open a new PR or replacement.