[llvm-commits] [llvm] r156114 - in /llvm/trunk: include/llvm/Transforms/Utils/FunctionUtils.h lib/Transforms/Utils/CodeExtractor.cpp
Chandler Carruth
chandlerc at gmail.com
Thu May 3 15:26:53 PDT 2012
Author: chandlerc
Date: Thu May 3 17:26:53 2012
New Revision: 156114
URL: http://llvm.org/viewvc/llvm-project?rev=156114&view=rev
Log:
Factor the logic for testing whether a basic block is viable for code
extraction into a public interface. Also clean it up and apply it more
consistently such that we check for landing pads *anywhere* in the
extracted code, not just in single-block extraction.
This will be used to guide decisions in passes that are planning to
eventually perform a round of code extraction.
Modified:
llvm/trunk/include/llvm/Transforms/Utils/FunctionUtils.h
llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp
Modified: llvm/trunk/include/llvm/Transforms/Utils/FunctionUtils.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/FunctionUtils.h?rev=156114&r1=156113&r2=156114&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/FunctionUtils.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/FunctionUtils.h Thu May 3 17:26:53 2012
@@ -23,6 +23,14 @@
class Function;
class Loop;
+ /// \brief Test whether a basic block is a viable candidate for extraction.
+ ///
+ /// This tests whether a particular basic block is viable for extraction into
+ /// a separate function. It can be used to prune code extraction eagerly
+ /// rather than waiting for one of the Extract* methods below to reject
+ /// a request.
+ bool isBlockViableForExtraction(const BasicBlock &BB);
+
/// ExtractCodeRegion - Rip out a sequence of basic blocks into a new
/// function.
///
Modified: llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp?rev=156114&r1=156113&r2=156114&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/CodeExtractor.cpp Thu May 3 17:26:53 2012
@@ -756,24 +756,31 @@
}
bool CodeExtractor::isEligible(ArrayRef<BasicBlock*> code) {
- // Deny a single basic block that's a landing pad block.
- if (code.size() == 1 && code[0]->isLandingPad())
- return false;
+ for (ArrayRef<BasicBlock*>::iterator I = code.begin(), E = code.end();
+ I != E; ++I)
+ if (!isBlockViableForExtraction(**I))
+ return false;
- // Deny code region if it contains allocas or vastarts.
- for (ArrayRef<BasicBlock*>::iterator BB = code.begin(), e=code.end();
- BB != e; ++BB)
- for (BasicBlock::const_iterator I = (*BB)->begin(), Ie = (*BB)->end();
- I != Ie; ++I)
- if (isa<AllocaInst>(*I))
- return false;
- else if (const CallInst *CI = dyn_cast<CallInst>(I))
- if (const Function *F = CI->getCalledFunction())
- if (F->getIntrinsicID() == Intrinsic::vastart)
- return false;
return true;
}
+bool llvm::isBlockViableForExtraction(const BasicBlock &BB) {
+ // Landing pads must be in the function where they were inserted for cleanup.
+ if (BB.isLandingPad())
+ return false;
+
+ // Don't hoist code containing allocas, invokes, or vastarts.
+ for (BasicBlock::const_iterator I = BB.begin(), E = BB.end(); I != E; ++I) {
+ if (isa<AllocaInst>(I) || isa<InvokeInst>(I))
+ return false;
+ if (const CallInst *CI = dyn_cast<CallInst>(I))
+ if (const Function *F = CI->getCalledFunction())
+ if (F->getIntrinsicID() == Intrinsic::vastart)
+ return false;
+ }
+
+ return true;
+}
/// ExtractCodeRegion - Slurp a sequence of basic blocks into a brand new
/// function.
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