From eb25bd2356cca5ef83472b1ae0f764037b82ad82 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Wed, 30 May 2012 00:42:39 +0000 Subject: [PATCH] Teach taildup to update livein set. rdar://11538365 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157663 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/TailDuplication.cpp | 25 ++++ test/CodeGen/ARM/2012-05-29-TailDupBug.ll | 140 ++++++++++++++++++++++ 2 files changed, 165 insertions(+) create mode 100644 test/CodeGen/ARM/2012-05-29-TailDupBug.ll diff --git a/lib/CodeGen/TailDuplication.cpp b/lib/CodeGen/TailDuplication.cpp index 3e203850f90..d077b091937 100644 --- a/lib/CodeGen/TailDuplication.cpp +++ b/lib/CodeGen/TailDuplication.cpp @@ -20,7 +20,9 @@ #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/MachineSSAUpdater.h" +#include "llvm/CodeGen/RegisterScavenging.h" #include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetRegisterInfo.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" @@ -57,8 +59,10 @@ namespace { /// TailDuplicatePass - Perform tail duplication. class TailDuplicatePass : public MachineFunctionPass { const TargetInstrInfo *TII; + const TargetRegisterInfo *TRI; MachineModuleInfo *MMI; MachineRegisterInfo *MRI; + RegScavenger *RS; bool PreRegAlloc; // SSAUpdateVRs - A list of virtual registers for which to update SSA form. @@ -124,9 +128,13 @@ INITIALIZE_PASS(TailDuplicatePass, "tailduplication", "Tail Duplication", bool TailDuplicatePass::runOnMachineFunction(MachineFunction &MF) { TII = MF.getTarget().getInstrInfo(); + TRI = MF.getTarget().getRegisterInfo(); MRI = &MF.getRegInfo(); MMI = getAnalysisIfAvailable(); PreRegAlloc = MRI->isSSA(); + RS = NULL; + if (MRI->tracksLiveness() && TRI->trackLivenessAfterRegAlloc(MF)) + RS = new RegScavenger(); bool MadeChange = false; while (TailDuplicateBlocks(MF)) @@ -777,6 +785,23 @@ TailDuplicatePass::TailDuplicate(MachineBasicBlock *TailBB, // Remove PredBB's unconditional branch. TII->RemoveBranch(*PredBB); + if (RS && !TailBB->livein_empty()) { + // Update PredBB livein. + RS->enterBasicBlock(PredBB); + if (!PredBB->empty()) + RS->forward(prior(PredBB->end())); + BitVector RegsLiveAtExit(TRI->getNumRegs()); + RS->getRegsUsed(RegsLiveAtExit, false); + for (MachineBasicBlock::livein_iterator I = TailBB->livein_begin(), + E = TailBB->livein_end(); I != E; ++I) { + if (!RegsLiveAtExit[*I]) + // If a register is previously livein to the tail but it's not live + // at the end of predecessor BB, then it should be added to its + // livein list. + PredBB->addLiveIn(*I); + } + } + // Clone the contents of TailBB into PredBB. DenseMap LocalVRMap; SmallVector, 4> CopyInfos; diff --git a/test/CodeGen/ARM/2012-05-29-TailDupBug.ll b/test/CodeGen/ARM/2012-05-29-TailDupBug.ll new file mode 100644 index 00000000000..1a57f04f645 --- /dev/null +++ b/test/CodeGen/ARM/2012-05-29-TailDupBug.ll @@ -0,0 +1,140 @@ +; RUN: llc -mtriple=thumbv7-apple-ios -mcpu=cortex-a8 -verify-machineinstrs < %s + +; Teach taildup to update livein set to appease verifier. +; rdar://11538365 + +%struct.__CFString.2 = type opaque + +declare void @CFRelease(i8*) + +define hidden fastcc i32 @t() ssp { +entry: + %mylocale.i.i = alloca [256 x i8], align 1 + br i1 undef, label %return, label %CFStringIsHyphenationAvailableForLocale.exit + +CFStringIsHyphenationAvailableForLocale.exit: ; preds = %entry + br i1 undef, label %return, label %if.end + +if.end: ; preds = %CFStringIsHyphenationAvailableForLocale.exit + br i1 undef, label %if.end8.thread.i, label %if.then.i + +if.then.i: ; preds = %if.end + br i1 undef, label %if.end8.thread.i, label %if.end8.i + +if.end8.thread.i: ; preds = %if.then.i, %if.end + unreachable + +if.end8.i: ; preds = %if.then.i + br i1 undef, label %if.then11.i, label %__CFHyphenationPullTokenizer.exit + +if.then11.i: ; preds = %if.end8.i + unreachable + +__CFHyphenationPullTokenizer.exit: ; preds = %if.end8.i + br i1 undef, label %if.end68, label %if.then3 + +if.then3: ; preds = %__CFHyphenationPullTokenizer.exit + br i1 undef, label %cond.end, label %cond.false + +cond.false: ; preds = %if.then3 + br label %cond.end + +cond.end: ; preds = %cond.false, %if.then3 + br i1 undef, label %while.end, label %while.body + +while.body: ; preds = %cond.end + unreachable + +while.end: ; preds = %cond.end + br i1 undef, label %if.end5.i, label %if.then.i16 + +if.then.i16: ; preds = %while.end + br i1 undef, label %if.then4.i, label %if.end5.i + +if.then4.i: ; preds = %if.then.i16 + br i1 false, label %cleanup.thread, label %if.end.i20 + +if.end5.i: ; preds = %if.then.i16, %while.end + unreachable + +if.end.i20: ; preds = %if.then4.i + br label %for.body.i146.i + +for.body.i146.i: ; preds = %for.body.i146.i, %if.end.i20 + br i1 undef, label %if.end20.i, label %for.body.i146.i + +if.end20.i: ; preds = %for.body.i146.i + br i1 undef, label %cleanup.thread, label %if.end23.i + +if.end23.i: ; preds = %if.end20.i + br label %for.body.i94.i + +for.body.i94.i: ; preds = %for.body.i94.i, %if.end23.i + br i1 undef, label %if.then28.i, label %for.body.i94.i + +if.then28.i: ; preds = %for.body.i94.i + br i1 undef, label %cond.true.i26, label %land.lhs.true + +cond.true.i26: ; preds = %if.then28.i + br label %land.lhs.true + +land.lhs.true: ; preds = %cond.true.i26, %if.then28.i + br i1 false, label %cleanup.thread, label %if.end35 + +if.end35: ; preds = %land.lhs.true + br i1 undef, label %cleanup.thread, label %if.end45 + +if.end45: ; preds = %if.end35 + br i1 undef, label %if.then50, label %if.end.i37 + +if.end.i37: ; preds = %if.end45 + br label %if.then50 + +if.then50: ; preds = %if.end.i37, %if.end45 + br i1 undef, label %__CFHyphenationGetHyphensForString.exit, label %if.end.i + +if.end.i: ; preds = %if.then50 + br i1 undef, label %cleanup.i, label %cond.true.i + +cond.true.i: ; preds = %if.end.i + br i1 undef, label %for.cond16.preheader.i, label %for.cond57.preheader.i + +for.cond16.preheader.i: ; preds = %cond.true.i + %cmp1791.i = icmp sgt i32 undef, 1 + br i1 %cmp1791.i, label %for.body18.i, label %for.cond57.preheader.i + +for.cond57.preheader.i: ; preds = %for.cond16.preheader.i, %cond.true.i + %sub69.i = add i32 undef, -2 + br label %cleanup.i + +for.body18.i: ; preds = %for.cond16.preheader.i + store i16 0, i16* undef, align 2 + br label %while.body.i + +while.body.i: ; preds = %while.body.i, %for.body18.i + br label %while.body.i + +cleanup.i: ; preds = %for.cond57.preheader.i, %if.end.i + br label %__CFHyphenationGetHyphensForString.exit + +__CFHyphenationGetHyphensForString.exit: ; preds = %cleanup.i, %if.then50 + %retval.1.i = phi i32 [ 0, %cleanup.i ], [ -1, %if.then50 ] + %phitmp = bitcast %struct.__CFString.2* null to i8* + br label %if.end68 + +cleanup.thread: ; preds = %if.end35, %land.lhs.true, %if.end20.i, %if.then4.i + call void @llvm.stackrestore(i8* null) + br label %return + +if.end68: ; preds = %__CFHyphenationGetHyphensForString.exit, %__CFHyphenationPullTokenizer.exit + %hyphenCount.2 = phi i32 [ %retval.1.i, %__CFHyphenationGetHyphensForString.exit ], [ 0, %__CFHyphenationPullTokenizer.exit ] + %_token.1 = phi i8* [ %phitmp, %__CFHyphenationGetHyphensForString.exit ], [ undef, %__CFHyphenationPullTokenizer.exit ] + call void @CFRelease(i8* %_token.1) + br label %return + +return: ; preds = %if.end68, %cleanup.thread, %CFStringIsHyphenationAvailableForLocale.exit, %entry + %retval.1 = phi i32 [ %hyphenCount.2, %if.end68 ], [ -1, %CFStringIsHyphenationAvailableForLocale.exit ], [ -1, %cleanup.thread ], [ -1, %entry ] + ret i32 %retval.1 +} + +declare void @llvm.stackrestore(i8*) nounwind