+/// isUsedOutsideOfBlock - Return true if there are any uses of I outside of the
+/// specified block. Note that PHI nodes are considered to evaluate their
+/// operands in the corresponding predecessor block.
+bool Instruction::isUsedOutsideOfBlock(const BasicBlock *BB) const {
+ for (use_const_iterator UI = use_begin(), E = use_end(); UI != E; ++UI) {
+ // PHI nodes uses values in the corresponding predecessor block. For other
+ // instructions, just check to see whether the parent of the use matches up.
+ const PHINode *PN = dyn_cast<PHINode>(*UI);
+ if (PN == 0) {
+ if (cast<Instruction>(*UI)->getParent() != BB)
+ return true;
+ continue;
+ }
+
+ unsigned UseOperand = UI.getOperandNo();
+ if (PN->getIncomingBlock(UseOperand/2) != BB)
+ return true;
+ }
+ return false;
+}
+
+/// mayReadFromMemory - Return true if this instruction may read memory.
+///
+bool Instruction::mayReadFromMemory() const {
+ switch (getOpcode()) {
+ default: return false;
+ case Instruction::Free:
+ case Instruction::VAArg:
+ case Instruction::Load:
+ return true;
+ case Instruction::Call:
+ return !cast<CallInst>(this)->doesNotAccessMemory();
+ case Instruction::Invoke:
+ return !cast<InvokeInst>(this)->doesNotAccessMemory();
+ case Instruction::Store:
+ return cast<StoreInst>(this)->isVolatile();
+ }
+}
+
+/// mayWriteToMemory - Return true if this instruction may modify memory.
+///
+bool Instruction::mayWriteToMemory() const {
+ switch (getOpcode()) {
+ default: return false;
+ case Instruction::Free:
+ case Instruction::Store:
+ case Instruction::VAArg:
+ return true;
+ case Instruction::Call:
+ return !cast<CallInst>(this)->onlyReadsMemory();
+ case Instruction::Invoke:
+ return !cast<InvokeInst>(this)->onlyReadsMemory();
+ case Instruction::Load:
+ return cast<LoadInst>(this)->isVolatile();
+ }
+}