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Revert "Fix a quadratic algorithm in MachineBranchProbabilityInfo."

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It caused an assertion failure when compiling consumer-typeset.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161463 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2012-08-08 01:10:31 +00:00
parent 39ad568c62
commit 913ff09a9a
4 changed files with 13 additions and 23 deletions
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2
include/llvm/CodeGen/MachineBasicBlock.h
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@ -572,7 +572,7 @@ private:
/// getSuccWeight - Return weight of the edge from this block to MBB. This /// getSuccWeight - Return weight of the edge from this block to MBB. This
/// method should NOT be called directly, but by using getEdgeWeight method /// method should NOT be called directly, but by using getEdgeWeight method
/// from MachineBranchProbabilityInfo class. /// from MachineBranchProbabilityInfo class.
uint32_t getSuccWeight(const_succ_iterator Succ) const; uint32_t getSuccWeight(const MachineBasicBlock *succ) const;
// Methods used to maintain doubly linked list of blocks... // Methods used to maintain doubly linked list of blocks...

9
include/llvm/CodeGen/MachineBranchProbabilityInfo.h
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@ -16,12 +16,14 @@
#define LLVM_CODEGEN_MACHINEBRANCHPROBABILITYINFO_H #define LLVM_CODEGEN_MACHINEBRANCHPROBABILITYINFO_H
#include "llvm/Pass.h" #include "llvm/Pass.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/Support/BranchProbability.h" #include "llvm/Support/BranchProbability.h"
#include <climits> #include <climits>
namespace llvm { namespace llvm {
class raw_ostream;
class MachineBasicBlock;
class MachineBranchProbabilityInfo : public ImmutablePass { class MachineBranchProbabilityInfo : public ImmutablePass {
virtual void anchor(); virtual void anchor();
@ -50,11 +52,6 @@ public:
uint32_t getEdgeWeight(const MachineBasicBlock *Src, uint32_t getEdgeWeight(const MachineBasicBlock *Src,
const MachineBasicBlock *Dst) const; const MachineBasicBlock *Dst) const;
// Same thing, but using a const_succ_iterator from Src. This is faster when
// the iterator is already available.
uint32_t getEdgeWeight(const MachineBasicBlock *Src,
MachineBasicBlock::const_succ_iterator Dst) const;
// Get sum of the block successors' weights, potentially scaling them to fit // Get sum of the block successors' weights, potentially scaling them to fit
// within 32-bits. If scaling is required, sets Scale based on the necessary // within 32-bits. If scaling is required, sets Scale based on the necessary
// adjustment. Any edge weights used with the sum should be divided by Scale. // adjustment. Any edge weights used with the sum should be divided by Scale.

5
lib/CodeGen/MachineBasicBlock.cpp
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@ -912,11 +912,12 @@ MachineBasicBlock::findDebugLoc(instr_iterator MBBI) {
/// getSuccWeight - Return weight of the edge from this block to MBB. /// getSuccWeight - Return weight of the edge from this block to MBB.
/// ///
uint32_t MachineBasicBlock::getSuccWeight(const_succ_iterator Succ) const { uint32_t MachineBasicBlock::getSuccWeight(const MachineBasicBlock *succ) const {
if (Weights.empty()) if (Weights.empty())
return 0; return 0;
return *getWeightIterator(Succ); const_succ_iterator I = std::find(Successors.begin(), Successors.end(), succ);
return *getWeightIterator(I);
} }
/// getWeightIterator - Return wight iterator corresonding to the I successor /// getWeightIterator - Return wight iterator corresonding to the I successor

20
lib/CodeGen/MachineBranchProbabilityInfo.cpp
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@ -38,7 +38,7 @@ getSumForBlock(const MachineBasicBlock *MBB, uint32_t &Scale) const {
Scale = 1; Scale = 1;
for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(),
E = MBB->succ_end(); I != E; ++I) { E = MBB->succ_end(); I != E; ++I) {
uint32_t Weight = getEdgeWeight(MBB, I); uint32_t Weight = getEdgeWeight(MBB, *I);
Sum += Weight; Sum += Weight;
} }
@ -53,30 +53,22 @@ getSumForBlock(const MachineBasicBlock *MBB, uint32_t &Scale) const {
Sum = 0; Sum = 0;
for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(),
E = MBB->succ_end(); I != E; ++I) { E = MBB->succ_end(); I != E; ++I) {
uint32_t Weight = getEdgeWeight(MBB, I); uint32_t Weight = getEdgeWeight(MBB, *I);
Sum += Weight / Scale; Sum += Weight / Scale;
} }
assert(Sum <= UINT32_MAX); assert(Sum <= UINT32_MAX);
return Sum; return Sum;
} }
uint32_t MachineBranchProbabilityInfo:: uint32_t
getEdgeWeight(const MachineBasicBlock *Src, MachineBranchProbabilityInfo::getEdgeWeight(const MachineBasicBlock *Src,
MachineBasicBlock::const_succ_iterator Dst) const { const MachineBasicBlock *Dst) const {
uint32_t Weight = Src->getSuccWeight(Dst); uint32_t Weight = Src->getSuccWeight(Dst);
if (!Weight) if (!Weight)
return DEFAULT_WEIGHT; return DEFAULT_WEIGHT;
return Weight; return Weight;
} }
uint32_t MachineBranchProbabilityInfo::
getEdgeWeight(const MachineBasicBlock *Src,
const MachineBasicBlock *Dst) const {
// This is a linear search. Try to use the const_succ_iterator version when
// possible.
return getEdgeWeight(Src, std::find(Src->succ_begin(), Src->succ_end(), Dst));
}
bool MachineBranchProbabilityInfo::isEdgeHot(MachineBasicBlock *Src, bool MachineBranchProbabilityInfo::isEdgeHot(MachineBasicBlock *Src,
MachineBasicBlock *Dst) const { MachineBasicBlock *Dst) const {
// Hot probability is at least 4/5 = 80% // Hot probability is at least 4/5 = 80%
@ -90,7 +82,7 @@ MachineBranchProbabilityInfo::getHotSucc(MachineBasicBlock *MBB) const {
MachineBasicBlock *MaxSucc = 0; MachineBasicBlock *MaxSucc = 0;
for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(),
E = MBB->succ_end(); I != E; ++I) { E = MBB->succ_end(); I != E; ++I) {
uint32_t Weight = getEdgeWeight(MBB, I); uint32_t Weight = getEdgeWeight(MBB, *I);
if (Weight > MaxWeight) { if (Weight > MaxWeight) {
MaxWeight = Weight; MaxWeight = Weight;
MaxSucc = *I; MaxSucc = *I;