diff options
| -rw-r--r-- | lib/CodeGen/IfConversion.cpp | 39 | ||||
| -rw-r--r-- | test/CodeGen/ARM/ifcvt4.ll | 10 | ||||
| -rw-r--r-- | test/CodeGen/ARM/indirectbr.ll | 1 | ||||
| -rw-r--r-- | test/CodeGen/Thumb2/2010-06-21-TailMergeBug.ll | 18 | ||||
| -rw-r--r-- | test/CodeGen/Thumb2/thumb2-ifcvt1.ll | 8 |
5 files changed, 29 insertions, 47 deletions
diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp index 6cb2277..c4e274d 100644 --- a/lib/CodeGen/IfConversion.cpp +++ b/lib/CodeGen/IfConversion.cpp @@ -16,14 +16,13 @@ #include "llvm/Function.h" #include "llvm/CodeGen/Passes.h" #include "llvm/CodeGen/MachineModuleInfo.h" +#include "llvm/Codegen/MachineBranchProbabilityInfo.h" #include "llvm/CodeGen/MachineFunctionPass.h" -#include "llvm/CodeGen/MachineLoopInfo.h" #include "llvm/MC/MCInstrItineraries.h" #include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetLowering.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Target/TargetRegisterInfo.h" -#include "llvm/Support/BranchProbability.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" @@ -154,7 +153,8 @@ namespace { const TargetInstrInfo *TII; const TargetRegisterInfo *TRI; const InstrItineraryData *InstrItins; - const MachineLoopInfo *MLI; + const MachineBranchProbabilityInfo *MBPI; + bool MadeChange; int FnNum; public: @@ -162,9 +162,9 @@ namespace { IfConverter() : MachineFunctionPass(ID), FnNum(-1) { initializeIfConverterPass(*PassRegistry::getPassRegistry()); } - + virtual void getAnalysisUsage(AnalysisUsage &AU) const { - AU.addRequired<MachineLoopInfo>(); + AU.addRequired<MachineBranchProbabilityInfo>(); MachineFunctionPass::getAnalysisUsage(AU); } @@ -252,7 +252,7 @@ namespace { } INITIALIZE_PASS_BEGIN(IfConverter, "if-converter", "If Converter", false, false) -INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo) +INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo) INITIALIZE_PASS_END(IfConverter, "if-converter", "If Converter", false, false) FunctionPass *llvm::createIfConverterPass() { return new IfConverter(); } @@ -261,7 +261,7 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) { TLI = MF.getTarget().getTargetLowering(); TII = MF.getTarget().getInstrInfo(); TRI = MF.getTarget().getRegisterInfo(); - MLI = &getAnalysis<MachineLoopInfo>(); + MBPI = &getAnalysis<MachineBranchProbabilityInfo>(); InstrItins = MF.getTarget().getInstrItineraryData(); if (!TII) return false; @@ -790,28 +790,9 @@ IfConverter::BBInfo &IfConverter::AnalyzeBlock(MachineBasicBlock *BB, bool TNeedSub = TrueBBI.Predicate.size() > 0; bool FNeedSub = FalseBBI.Predicate.size() > 0; bool Enqueued = false; - - // Try to predict the branch, using loop info to guide us. - // General heuristics are: - // - backedge -> 90% taken - // - early exit -> 20% taken - // - branch predictor confidence -> 90% - BranchProbability Prediction(5, 10); - MachineLoop *Loop = MLI->getLoopFor(BB); - if (Loop) { - if (TrueBBI.BB == Loop->getHeader()) - Prediction = BranchProbability(9, 10); - else if (FalseBBI.BB == Loop->getHeader()) - Prediction = BranchProbability(1, 10); - - MachineLoop *TrueLoop = MLI->getLoopFor(TrueBBI.BB); - MachineLoop *FalseLoop = MLI->getLoopFor(FalseBBI.BB); - if (!TrueLoop || TrueLoop->getParentLoop() == Loop) - Prediction = BranchProbability(2, 10); - else if (!FalseLoop || FalseLoop->getParentLoop() == Loop) - Prediction = BranchProbability(8, 10); - } - + + BranchProbability Prediction = MBPI->getEdgeProbability(BB, TrueBBI.BB); + if (CanRevCond && ValidDiamond(TrueBBI, FalseBBI, Dups, Dups2) && MeetIfcvtSizeLimit(*TrueBBI.BB, (TrueBBI.NonPredSize - (Dups + Dups2) + TrueBBI.ExtraCost), TrueBBI.ExtraCost2, diff --git a/test/CodeGen/ARM/ifcvt4.ll b/test/CodeGen/ARM/ifcvt4.ll index f28c61b..d099f51 100644 --- a/test/CodeGen/ARM/ifcvt4.ll +++ b/test/CodeGen/ARM/ifcvt4.ll @@ -1,8 +1,10 @@ -; RUN: llc < %s -march=arm -; RUN: llc < %s -march=arm | grep subgt | count 1 -; RUN: llc < %s -march=arm | grep suble | count 1 -; FIXME: Check for # of unconditional branch after adding branch folding post ifcvt. +; RUN: llc < %s -march=arm | FileCheck %s +; Do not if-convert when branches go to the different loops. +; CHECK: _t: +; CHECK-NOT: subgt +; CHECK-NOT: suble +; Don't use define i32 @t(i32 %a, i32 %b) { entry: %tmp1434 = icmp eq i32 %a, %b ; <i1> [#uses=1] diff --git a/test/CodeGen/ARM/indirectbr.ll b/test/CodeGen/ARM/indirectbr.ll index 25a0f93..341c33f 100644 --- a/test/CodeGen/ARM/indirectbr.ll +++ b/test/CodeGen/ARM/indirectbr.ll @@ -22,7 +22,6 @@ bb2: ; preds = %entry, %bb3 %gotovar.4.0 = phi i8* [ %gotovar.4.0.pre, %bb3 ], [ %0, %entry ] ; <i8*> [#uses=1] ; ARM: bx ; THUMB: mov pc, -; THUMB2: mov pc, indirectbr i8* %gotovar.4.0, [label %L5, label %L4, label %L3, label %L2, label %L1] bb3: ; preds = %entry diff --git a/test/CodeGen/Thumb2/2010-06-21-TailMergeBug.ll b/test/CodeGen/Thumb2/2010-06-21-TailMergeBug.ll index f91e1c9..244d0bb 100644 --- a/test/CodeGen/Thumb2/2010-06-21-TailMergeBug.ll +++ b/test/CodeGen/Thumb2/2010-06-21-TailMergeBug.ll @@ -32,15 +32,15 @@ define fastcc i32 @parse_percent_token() nounwind { entry: -; CHECK: ittt eq -; CHECK: ittt eq -; CHECK: ittt eq -; CHECK: ittt eq -; CHECK: ittt eq -; CHECK: moveq r0 -; CHECK-NOT: LBB0_ -; CHECK: ldreq -; CHECK: popeq +; CHECK: pop +; CHECK: pop +; CHECK: pop +; CHECK: pop +; CHECK: pop +; CHECK: pop +; CHECK: pop +; Do not convert into single stream code. BranchProbability Analysis assumes +; that branches which goes to "ret" intruction have lower probabilities. switch i32 undef, label %bb7 [ i32 37, label %bb43 i32 48, label %bb5 diff --git a/test/CodeGen/Thumb2/thumb2-ifcvt1.ll b/test/CodeGen/Thumb2/thumb2-ifcvt1.ll index a4035bb..af8fcc6 100644 --- a/test/CodeGen/Thumb2/thumb2-ifcvt1.ll +++ b/test/CodeGen/Thumb2/thumb2-ifcvt1.ll @@ -21,13 +21,13 @@ cond_next: ret i32 %tmp15 } -; FIXME: Check for # of unconditional branch after adding branch folding post ifcvt. define i32 @t2(i32 %a, i32 %b) nounwind { entry: +; Do not if-convert when branches go to the different loops. ; CHECK: t2: -; CHECK: ite gt -; CHECK: subgt -; CHECK: suble +; CHECK-NOT: ite gt +; CHECK-NOT: subgt +; CHECK-NOT: suble %tmp1434 = icmp eq i32 %a, %b ; <i1> [#uses=1] br i1 %tmp1434, label %bb17, label %bb.outer |