[llvm-commits] [llvm] r161062 - in /llvm/trunk: lib/CodeGen/MachineSink.cpp test/CodeGen/X86/sink-out-of-loop.ll

[Manman Ren]

Yes, I will make the change.

Thanks,
Manman
On Jul 31, 2012, at 12:39 PM, Evan Cheng wrote:

> Hi Manman,
> 
> Is it possible for multiple successors to have the same loop depth? If so, should they be sorted with stable_sort instead?
> 
> Evan
> 
> On Jul 31, 2012, at 11:10 AM, Manman Ren <mren at apple.com> wrote:
> 
>> Author: mren
>> Date: Tue Jul 31 13:10:39 2012
>> New Revision: 161062
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=161062&view=rev
>> Log:
>> MachineSink: Sort the successors before trying to find SuccToSinkTo.
>> 
>> One motivating example is to sink an instruction from a basic block which has
>> two successors: one outside the loop, the other inside the loop. We should try
>> to sink the instruction outside the loop.
>> 
>> rdar://11980766
>> 
>> Added:
>>   llvm/trunk/test/CodeGen/X86/sink-out-of-loop.ll
>> Modified:
>>   llvm/trunk/lib/CodeGen/MachineSink.cpp
>> 
>> Modified: llvm/trunk/lib/CodeGen/MachineSink.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineSink.cpp?rev=161062&r1=161061&r2=161062&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/CodeGen/MachineSink.cpp (original)
>> +++ llvm/trunk/lib/CodeGen/MachineSink.cpp Tue Jul 31 13:10:39 2012
>> @@ -99,6 +99,16 @@
>>    bool PerformTrivialForwardCoalescing(MachineInstr *MI,
>>                                         MachineBasicBlock *MBB);
>>  };
>> +
>> +  // SuccessorSorter - Sort Successors according to their loop depth. 
>> +  struct SuccessorSorter {
>> +    SuccessorSorter(MachineLoopInfo *LoopInfo) : LI(LoopInfo) {}
>> +    bool operator()(const MachineBasicBlock *LHS,
>> +                    const MachineBasicBlock *RHS) const {
>> +      return LI->getLoopDepth(LHS) < LI->getLoopDepth(RHS);
>> +    }
>> +    MachineLoopInfo *LI;
>> +  };
>> } // end anonymous namespace
>> 
>> char MachineSinking::ID = 0;
>> @@ -526,8 +536,11 @@
>> 
>>      // Otherwise, we should look at all the successors and decide which one
>>      // we should sink to.
>> -      for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
>> -           E = MBB->succ_end(); SI != E; ++SI) {
>> +      // We give successors with smaller loop depth higher priority.
>> +      SmallVector<MachineBasicBlock*, 4> Succs(MBB->succ_begin(), MBB->succ_end());
>> +      std::sort(Succs.begin(), Succs.end(), SuccessorSorter(LI));
>> +      for (SmallVector<MachineBasicBlock*, 4>::iterator SI = Succs.begin(),
>> +           E = Succs.end(); SI != E; ++SI) {
>>        MachineBasicBlock *SuccBlock = *SI;
>>        bool LocalUse = false;
>>        if (AllUsesDominatedByBlock(Reg, SuccBlock, MBB,
>> 
>> Added: llvm/trunk/test/CodeGen/X86/sink-out-of-loop.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sink-out-of-loop.ll?rev=161062&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/CodeGen/X86/sink-out-of-loop.ll (added)
>> +++ llvm/trunk/test/CodeGen/X86/sink-out-of-loop.ll Tue Jul 31 13:10:39 2012
>> @@ -0,0 +1,54 @@
>> +; RUN: llc -mtriple=x86_64-apple-darwin < %s | FileCheck %s
>> +
>> +; A MOV32ri is inside a loop, it has two successors, one successor is inside the
>> +; same loop, the other successor is outside the loop. We should be able to sink
>> +; MOV32ri outside the loop.
>> +; rdar://11980766
>> +define i32 @sink_succ(i32 %argc, i8** nocapture %argv) nounwind uwtable ssp {
>> +; CHECK: sink_succ
>> +; CHECK: [[OUTER_LN1:LBB0_[0-9]+]]: ## %preheader
>> +; CHECK: %exit
>> +; CHECK-NOT: movl
>> +; CHECK: jne [[OUTER_LN1]]
>> +; CHECK: movl
>> +; CHECK: [[LN2:LBB0_[0-9]+]]: ## %for.body2
>> +; CHECK: jne [[LN2]]
>> +; CHECK: ret
>> +entry:
>> +  br label %preheader
>> +
>> +preheader:
>> +  %i.127 = phi i32 [ 0, %entry ], [ %inc9, %exit ]
>> +  br label %for.body1.lr
>> +
>> +for.body1.lr:
>> +  %iv30 = phi i32 [ 1, %preheader ], [ %iv.next31, %for.inc40.i ]
>> +  br label %for.body1
>> +
>> +for.body1:
>> +  %iv.i = phi i64 [ 0, %for.body1.lr ], [ %iv.next.i, %for.body1 ]
>> +  %iv.next.i = add i64 %iv.i, 1
>> +  %lftr.wideiv32 = trunc i64 %iv.next.i to i32
>> +  %exitcond33 = icmp eq i32 %lftr.wideiv32, %iv30
>> +  br i1 %exitcond33, label %for.inc40.i, label %for.body1
>> +
>> +for.inc40.i:
>> +  %iv.next31 = add i32 %iv30, 1
>> +  %exitcond49.i = icmp eq i32 %iv.next31, 32
>> +  br i1 %exitcond49.i, label %exit, label %for.body1.lr
>> +
>> +exit:
>> +  %inc9 = add nsw i32 %i.127, 1
>> +  %exitcond34 = icmp eq i32 %inc9, 10
>> +  br i1 %exitcond34, label %for.body2, label %preheader
>> +
>> +for.body2:
>> +  %iv = phi i64 [ %iv.next, %for.body2 ], [ 0, %exit ]
>> +  %iv.next = add i64 %iv, 1
>> +  %lftr.wideiv = trunc i64 %iv.next to i32
>> +  %exitcond = icmp eq i32 %lftr.wideiv, 2048
>> +  br i1 %exitcond, label %for.end20, label %for.body2
>> +
>> +for.end20:
>> +  ret i32 0
>> +}
>> 
>> 
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