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Add a method to MachineInstr for testing whether it makes
any volatile memory references. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56528 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -250,8 +250,16 @@ public:
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/// the instruction's location and its intended destination.
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bool isSafeToMove(const TargetInstrInfo *TII, bool &SawStore);
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/// isSafeToReMat - Return true if it's safe to rematerialize the specified
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/// instruction which defined the specified register instead of copying it.
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bool isSafeToReMat(const TargetInstrInfo *TII, unsigned DstReg);
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/// hasVolatileMemoryRef - Return true if this instruction may have a
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/// volatile memory reference, or if the information describing the
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/// memory reference is not available. Return false if it is known to
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/// have no volatile memory references.
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bool hasVolatileMemoryRef() const;
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//
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// Debugging support
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//
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@ -711,16 +711,11 @@ bool MachineInstr::isSafeToMove(const TargetInstrInfo *TII, bool &SawStore) {
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// destination. The check for isInvariantLoad gives the targe the chance to
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// classify the load as always returning a constant, e.g. a constant pool
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// load.
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if (TID->mayLoad() && !TII->isInvariantLoad(this)) {
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if (TID->mayLoad() && !TII->isInvariantLoad(this))
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// Otherwise, this is a real load. If there is a store between the load and
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// end of block, we can't sink the load.
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//
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// FIXME: we can't do this transformation until we know that the load is
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// not volatile, and machineinstrs don't keep this info. :(
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//
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//if (SawStore)
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return false;
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}
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// end of block, or if the laod is volatile, we can't move it.
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return SawStore || hasVolatileMemoryRef();
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return true;
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}
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@ -749,6 +744,32 @@ bool MachineInstr::isSafeToReMat(const TargetInstrInfo *TII, unsigned DstReg) {
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return true;
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}
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/// hasVolatileMemoryRef - Return true if this instruction may have a
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/// volatile memory reference, or if the information describing the
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/// memory reference is not available. Return false if it is known to
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/// have no volatile memory references.
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bool MachineInstr::hasVolatileMemoryRef() const {
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// An instruction known never to access memory won't have a volatile access.
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if (!TID->mayStore() &&
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!TID->mayLoad() &&
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!TID->isCall() &&
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!TID->hasUnmodeledSideEffects())
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return false;
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// Otherwise, if the instruction has no memory reference information,
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// conservatively assume it wasn't preserved.
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if (memoperands_empty())
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return true;
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// Check the memory reference information for volatile references.
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for (std::list<MachineMemOperand>::const_iterator I = memoperands_begin(),
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E = memoperands_end(); I != E; ++I)
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if (I->isVolatile())
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return true;
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return false;
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}
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void MachineInstr::dump() const {
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cerr << " " << *this;
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}
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