[llvm-commits] [llvm] r161062 - in /llvm/trunk: lib/CodeGen/MachineSink.cpp test/CodeGen/X86/sink-out-of-loop.ll
Manman Ren
mren at apple.com
Tue Jul 31 11:10:39 PDT 2012
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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