From 778ef97c76af82ef9e312529e6bd9d71d3c040ae Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Fri, 8 Mar 2013 18:08:57 +0000 Subject: [PATCH] Rewrite the physreg part of findLastUseBefore(). To find the last use of a register unit, start from the bottom and scan upwards until a user is found. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176706 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/LiveIntervalAnalysis.cpp | 60 +++++++++++++++++++++--------------- test/CodeGen/X86/misched-crash.ll | 40 ++++++++++++++++++++++++ 2 files changed, 76 insertions(+), 24 deletions(-) create mode 100644 test/CodeGen/X86/misched-crash.ll diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp index 22b35d5271e..f1b83948113 100644 --- a/lib/CodeGen/LiveIntervalAnalysis.cpp +++ b/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -972,9 +972,9 @@ private: // Return the last use of reg between NewIdx and OldIdx. SlotIndex findLastUseBefore(unsigned Reg) { - SlotIndex LastUse = NewIdx; if (TargetRegisterInfo::isVirtualRegister(Reg)) { + SlotIndex LastUse = NewIdx; for (MachineRegisterInfo::use_nodbg_iterator UI = MRI.use_nodbg_begin(Reg), UE = MRI.use_nodbg_end(); @@ -984,30 +984,42 @@ private: if (InstSlot > LastUse && InstSlot < OldIdx) LastUse = InstSlot; } - } else { - MachineInstr* MI = LIS.getSlotIndexes()->getInstructionFromIndex(NewIdx); - MachineBasicBlock::iterator MII(MI); - ++MII; - MachineBasicBlock* MBB = MI->getParent(); - for (; MII != MBB->end(); ++MII){ - if (MII->isDebugValue()) - continue; - if (LIS.getInstructionIndex(MII) < OldIdx) - break; - for (MachineInstr::mop_iterator MOI = MII->operands_begin(), - MOE = MII->operands_end(); - MOI != MOE; ++MOI) { - const MachineOperand& mop = *MOI; - if (!mop.isReg() || mop.getReg() == 0 || - TargetRegisterInfo::isVirtualRegister(mop.getReg())) - continue; - - if (TRI.hasRegUnit(mop.getReg(), Reg)) - LastUse = LIS.getInstructionIndex(MII); - } - } + return LastUse; + } + + // This is a regunit interval, so scanning the use list could be very + // expensive. Scan upwards from OldIdx instead. + assert(NewIdx < OldIdx && "Expected upwards move"); + SlotIndexes *Indexes = LIS.getSlotIndexes(); + MachineBasicBlock *MBB = Indexes->getMBBFromIndex(NewIdx); + + // OldIdx may not correspond to an instruction any longer, so set MII to + // point to the next instruction after OldIdx, or MBB->end(). + MachineBasicBlock::iterator MII = MBB->end(); + if (MachineInstr *MI = Indexes->getInstructionFromIndex( + Indexes->getNextNonNullIndex(OldIdx))) + if (MI->getParent() == MBB) + MII = MI; + + MachineBasicBlock::iterator Begin = MBB->begin(); + while (MII != Begin) { + if ((--MII)->isDebugValue()) + continue; + SlotIndex Idx = Indexes->getInstructionIndex(MII); + + // Stop searching when NewIdx is reached. + if (!SlotIndex::isEarlierInstr(NewIdx, Idx)) + return NewIdx; + + // Check if MII uses Reg. + for (MIBundleOperands MO(MII); MO.isValid(); ++MO) + if (MO->isReg() && + TargetRegisterInfo::isPhysicalRegister(MO->getReg()) && + TRI.hasRegUnit(MO->getReg(), Reg)) + return Idx; } - return LastUse; + // Didn't reach NewIdx. It must be the first instruction in the block. + return NewIdx; } }; diff --git a/test/CodeGen/X86/misched-crash.ll b/test/CodeGen/X86/misched-crash.ll new file mode 100644 index 00000000000..7644ee07087 --- /dev/null +++ b/test/CodeGen/X86/misched-crash.ll @@ -0,0 +1,40 @@ +; RUN: llc < %s -enable-misched -verify-misched +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10" + +; This function contains a cmp instruction with two users. +; Hoisting the last use requires trimming the EFLAGS live range to the second. +define void @rdar13353090(i8* %plane, i64 %_x1, i64 %_x2) { +entry: + %cmp = icmp ult i64 %_x1, %_x2 + %cond = select i1 %cmp, i64 %_x1, i64 %_x2 + %cond10 = select i1 %cmp, i64 %_x2, i64 %_x1 + %0 = load i64* null, align 8 + %cmp16 = icmp ult i64 %cond, %0 + %cmp23 = icmp ugt i64 %cond10, 0 + br i1 %cmp16, label %land.lhs.true21, label %return + +land.lhs.true21: ; preds = %entry + %sub = add i64 %0, -1 + br i1 %cmp23, label %if.then24, label %return + +if.then24: ; preds = %land.lhs.true21 + %cmp16.i = icmp ult i64 %cond, %sub + %cond20.i = select i1 %cmp16.i, i64 %cond, i64 %sub + %add21.i = add i64 0, %cond20.i + br label %for.body34.i + +for.body34.i: ; preds = %for.inc39.i, %if.then24 + %index.178.i = phi i64 [ %add21.i, %if.then24 ], [ %inc41.i, %for.inc39.i ] + %arrayidx35.i = getelementptr inbounds i8* %plane, i64 %index.178.i + %1 = load i8* %arrayidx35.i, align 1 + %tobool36.i = icmp eq i8 %1, 0 + br i1 %tobool36.i, label %for.inc39.i, label %return + +for.inc39.i: ; preds = %for.body34.i + %inc41.i = add i64 %index.178.i, 1 + br i1 undef, label %return, label %for.body34.i + +return: ; preds = %for.inc39.i, %for.body34.i, %land.lhs.true21, %entry + ret void +} -- 2.11.0