From aa9db70243d96a7904b10aaf2aa8315b13c14e2c Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 20 Apr 2008 22:11:30 +0000 Subject: add a handy helper method to instruction, useful for determining whether it is used outside of some block. This can be used to see if there are any non-local references, for example. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50004 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/VMCore/Instruction.cpp | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 'lib') diff --git a/lib/VMCore/Instruction.cpp b/lib/VMCore/Instruction.cpp index 6f09c90..5344cf7 100644 --- a/lib/VMCore/Instruction.cpp +++ b/lib/VMCore/Instruction.cpp @@ -198,6 +198,29 @@ bool Instruction::isSameOperationAs(Instruction *I) const { return true; } +/// 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(*UI); + if (PN == 0) { + if (cast(*UI)->getParent() != BB) + return true; + continue; + } + + unsigned UseOperand = UI.getOperandNo(); + if (PN->getIncomingBlock(UseOperand/2) != BB) + return true; + } + return false; +} + + + /// mayWriteToMemory - Return true if this instruction may modify memory. /// bool Instruction::mayWriteToMemory() const { -- cgit v1.1