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author | Evan Cheng <evan.cheng@apple.com> | 2008-03-13 00:44:09 +0000 |
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committer | Evan Cheng <evan.cheng@apple.com> | 2008-03-13 00:44:09 +0000 |
commit | be85662cf2ca0df74ad595ac2a2deae7e4799f6b (patch) | |
tree | d004a308e8429297ce4869ba39213069f4a1d949 /lib | |
parent | d24ed64de0739e3eca8c08e45c36b4f6e4d7d3a2 (diff) | |
download | external_llvm-be85662cf2ca0df74ad595ac2a2deae7e4799f6b.zip external_llvm-be85662cf2ca0df74ad595ac2a2deae7e4799f6b.tar.gz external_llvm-be85662cf2ca0df74ad595ac2a2deae7e4799f6b.tar.bz2 |
Refactor some code out of MachineSink into a MachineInstr query.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48311 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/CodeGen/MachineInstr.cpp | 42 | ||||
-rw-r--r-- | lib/CodeGen/MachineSink.cpp | 25 |
2 files changed, 38 insertions, 29 deletions
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp index b396382..265a330 100644 --- a/lib/CodeGen/MachineInstr.cpp +++ b/lib/CodeGen/MachineInstr.cpp @@ -628,16 +628,46 @@ void MachineInstr::copyKillDeadInfo(const MachineInstr *MI) { /// copyPredicates - Copies predicate operand(s) from MI. void MachineInstr::copyPredicates(const MachineInstr *MI) { const TargetInstrDesc &TID = MI->getDesc(); - if (TID.isPredicable()) { - for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { - if (TID.OpInfo[i].isPredicate()) { - // Predicated operands must be last operands. - addOperand(MI->getOperand(i)); - } + if (!TID.isPredicable()) + return; + for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { + if (TID.OpInfo[i].isPredicate()) { + // Predicated operands must be last operands. + addOperand(MI->getOperand(i)); } } } +/// isSafeToMove - Return true if it is safe to this instruction. If SawStore +/// true, it means there is a store (or call) between the instruction the +/// localtion and its intended destination. +bool MachineInstr::isSafeToMove(const TargetInstrInfo *TII, bool &SawStore) { + // Ignore stuff that we obviously can't move. + if (TID->mayStore() || TID->isCall()) { + SawStore = true; + return false; + } + if (TID->isReturn() || TID->isBranch() || TID->hasUnmodeledSideEffects()) + return false; + + // See if this instruction does a load. If so, we have to guarantee that the + // loaded value doesn't change between the load and the its intended + // destination. The check for isInvariantLoad gives the targe the chance to + // classify the load as always returning a constant, e.g. a constant pool + // load. + if (TID->mayLoad() && !TII->isInvariantLoad(this)) { + // Otherwise, this is a real load. If there is a store between the load and + // end of block, we can't sink the load. + // + // FIXME: we can't do this transformation until we know that the load is + // not volatile, and machineinstrs don't keep this info. :( + // + //if (SawStore) + return false; + } + return true; +} + void MachineInstr::dump() const { cerr << " " << *this; } diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp index db2fab0..97a4df5 100644 --- a/lib/CodeGen/MachineSink.cpp +++ b/lib/CodeGen/MachineSink.cpp @@ -132,30 +132,9 @@ bool MachineSinking::ProcessBlock(MachineBasicBlock &MBB) { /// SinkInstruction - Determine whether it is safe to sink the specified machine /// instruction out of its current block into a successor. bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) { - const TargetInstrDesc &TID = MI->getDesc(); - - // Ignore stuff that we obviously can't sink. - if (TID.mayStore() || TID.isCall()) { - SawStore = true; - return false; - } - if (TID.isReturn() || TID.isBranch() || TID.hasUnmodeledSideEffects()) + // Check if it's safe to move the instruction. + if (!MI->isSafeToMove(TII, SawStore)) return false; - - // See if this instruction does a load. If so, we have to guarantee that the - // loaded value doesn't change between the load and the end of block. The - // check for isInvariantLoad gives the targe the chance to classify the load - // as always returning a constant, e.g. a constant pool load. - if (TID.mayLoad() && !TII->isInvariantLoad(MI)) { - // Otherwise, this is a real load. If there is a store between the load and - // end of block, we can't sink the load. - // - // FIXME: we can't do this transformation until we know that the load is - // not volatile, and machineinstrs don't keep this info. :( - // - //if (SawStore) - return false; - } // FIXME: This should include support for sinking instructions within the // block they are currently in to shorten the live ranges. We often get |