From 5e63d43e48f6d0b597d21b83a1eed9eaf2febc93 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Wed, 8 Aug 2012 00:20:37 +0000 Subject: Fix a quadratic algorithm in MachineBranchProbabilityInfo. The getSumForBlock function was quadratic in the number of successors because getSuccWeight would perform a linear search for an already known iterator. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161460 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/MachineBranchProbabilityInfo.cpp | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) (limited to 'lib/CodeGen/MachineBranchProbabilityInfo.cpp') diff --git a/lib/CodeGen/MachineBranchProbabilityInfo.cpp b/lib/CodeGen/MachineBranchProbabilityInfo.cpp index 0cc1af0..4479211 100644 --- a/lib/CodeGen/MachineBranchProbabilityInfo.cpp +++ b/lib/CodeGen/MachineBranchProbabilityInfo.cpp @@ -38,7 +38,7 @@ getSumForBlock(const MachineBasicBlock *MBB, uint32_t &Scale) const { Scale = 1; for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - uint32_t Weight = getEdgeWeight(MBB, *I); + uint32_t Weight = getEdgeWeight(MBB, I); Sum += Weight; } @@ -53,22 +53,30 @@ getSumForBlock(const MachineBasicBlock *MBB, uint32_t &Scale) const { Sum = 0; for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - uint32_t Weight = getEdgeWeight(MBB, *I); + uint32_t Weight = getEdgeWeight(MBB, I); Sum += Weight / Scale; } assert(Sum <= UINT32_MAX); return Sum; } -uint32_t -MachineBranchProbabilityInfo::getEdgeWeight(const MachineBasicBlock *Src, - const MachineBasicBlock *Dst) const { +uint32_t MachineBranchProbabilityInfo:: +getEdgeWeight(const MachineBasicBlock *Src, + MachineBasicBlock::const_succ_iterator Dst) const { uint32_t Weight = Src->getSuccWeight(Dst); if (!Weight) return DEFAULT_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, MachineBasicBlock *Dst) const { // Hot probability is at least 4/5 = 80% @@ -82,7 +90,7 @@ MachineBranchProbabilityInfo::getHotSucc(MachineBasicBlock *MBB) const { MachineBasicBlock *MaxSucc = 0; for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - uint32_t Weight = getEdgeWeight(MBB, *I); + uint32_t Weight = getEdgeWeight(MBB, I); if (Weight > MaxWeight) { MaxWeight = Weight; MaxSucc = *I; -- cgit v1.1 From 913ff09a9acf563ae9719ff223bc117dd66ad6b0 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Wed, 8 Aug 2012 01:10:31 +0000 Subject: Revert "Fix a quadratic algorithm in MachineBranchProbabilityInfo." 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 --- lib/CodeGen/MachineBranchProbabilityInfo.cpp | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) (limited to 'lib/CodeGen/MachineBranchProbabilityInfo.cpp') diff --git a/lib/CodeGen/MachineBranchProbabilityInfo.cpp b/lib/CodeGen/MachineBranchProbabilityInfo.cpp index 4479211..0cc1af0 100644 --- a/lib/CodeGen/MachineBranchProbabilityInfo.cpp +++ b/lib/CodeGen/MachineBranchProbabilityInfo.cpp @@ -38,7 +38,7 @@ getSumForBlock(const MachineBasicBlock *MBB, uint32_t &Scale) const { Scale = 1; for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - uint32_t Weight = getEdgeWeight(MBB, I); + uint32_t Weight = getEdgeWeight(MBB, *I); Sum += Weight; } @@ -53,30 +53,22 @@ getSumForBlock(const MachineBasicBlock *MBB, uint32_t &Scale) const { Sum = 0; for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - uint32_t Weight = getEdgeWeight(MBB, I); + uint32_t Weight = getEdgeWeight(MBB, *I); Sum += Weight / Scale; } assert(Sum <= UINT32_MAX); return Sum; } -uint32_t MachineBranchProbabilityInfo:: -getEdgeWeight(const MachineBasicBlock *Src, - MachineBasicBlock::const_succ_iterator Dst) const { +uint32_t +MachineBranchProbabilityInfo::getEdgeWeight(const MachineBasicBlock *Src, + const MachineBasicBlock *Dst) const { uint32_t Weight = Src->getSuccWeight(Dst); if (!Weight) return DEFAULT_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, MachineBasicBlock *Dst) const { // Hot probability is at least 4/5 = 80% @@ -90,7 +82,7 @@ MachineBranchProbabilityInfo::getHotSucc(MachineBasicBlock *MBB) const { MachineBasicBlock *MaxSucc = 0; for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - uint32_t Weight = getEdgeWeight(MBB, I); + uint32_t Weight = getEdgeWeight(MBB, *I); if (Weight > MaxWeight) { MaxWeight = Weight; MaxSucc = *I; -- cgit v1.1 From 990ca5517fd6666d4049b6b8281d9df99da11637 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Mon, 20 Aug 2012 22:01:38 +0000 Subject: Fix a quadratic algorithm in MachineBranchProbabilityInfo. The getSumForBlock function was quadratic in the number of successors because getSuccWeight would perform a linear search for an already known iterator. This patch was originally committed as r161460, but reverted again because of assertion failures. Now that duplicate Machine CFG edges have been eliminated, this works properly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162233 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/MachineBranchProbabilityInfo.cpp | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) (limited to 'lib/CodeGen/MachineBranchProbabilityInfo.cpp') diff --git a/lib/CodeGen/MachineBranchProbabilityInfo.cpp b/lib/CodeGen/MachineBranchProbabilityInfo.cpp index 0cc1af0..4479211 100644 --- a/lib/CodeGen/MachineBranchProbabilityInfo.cpp +++ b/lib/CodeGen/MachineBranchProbabilityInfo.cpp @@ -38,7 +38,7 @@ getSumForBlock(const MachineBasicBlock *MBB, uint32_t &Scale) const { Scale = 1; for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - uint32_t Weight = getEdgeWeight(MBB, *I); + uint32_t Weight = getEdgeWeight(MBB, I); Sum += Weight; } @@ -53,22 +53,30 @@ getSumForBlock(const MachineBasicBlock *MBB, uint32_t &Scale) const { Sum = 0; for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - uint32_t Weight = getEdgeWeight(MBB, *I); + uint32_t Weight = getEdgeWeight(MBB, I); Sum += Weight / Scale; } assert(Sum <= UINT32_MAX); return Sum; } -uint32_t -MachineBranchProbabilityInfo::getEdgeWeight(const MachineBasicBlock *Src, - const MachineBasicBlock *Dst) const { +uint32_t MachineBranchProbabilityInfo:: +getEdgeWeight(const MachineBasicBlock *Src, + MachineBasicBlock::const_succ_iterator Dst) const { uint32_t Weight = Src->getSuccWeight(Dst); if (!Weight) return DEFAULT_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, MachineBasicBlock *Dst) const { // Hot probability is at least 4/5 = 80% @@ -82,7 +90,7 @@ MachineBranchProbabilityInfo::getHotSucc(MachineBasicBlock *MBB) const { MachineBasicBlock *MaxSucc = 0; for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(), E = MBB->succ_end(); I != E; ++I) { - uint32_t Weight = getEdgeWeight(MBB, *I); + uint32_t Weight = getEdgeWeight(MBB, I); if (Weight > MaxWeight) { MaxWeight = Weight; MaxSucc = *I; -- cgit v1.1