From 69d03cf2eeabcac172be96eb6b94e454dc33018c Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Thu, 16 Jul 2009 16:16:23 +0000 Subject: [PATCH] Add an isLoopSimplifyForm() predicate, following the example of isLCSSAForm(), to test whether a loop is in the form guaranteed by the LoopSimplify pass. llvm-svn: 76077 --- include/llvm/Analysis/LoopInfo.h | 5 +++++ lib/Analysis/LoopInfo.cpp | 24 ++++++++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h index 60c9564222a..7ce6a4eddab 100644 --- a/include/llvm/Analysis/LoopInfo.h +++ b/include/llvm/Analysis/LoopInfo.h @@ -551,6 +551,11 @@ public: /// isLCSSAForm - Return true if the Loop is in LCSSA form bool isLCSSAForm() const; + /// isLoopSimplifyForm - Return true if the Loop is in the form that + /// the LoopSimplify form transforms loops to, which is sometimes called + /// normal form. + bool isLoopSimplifyForm() const; + private: friend class LoopInfoBase; explicit Loop(BasicBlock *BB) : LoopBase(BB) {} diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp index 63de1aa7aee..d350fa6f9eb 100644 --- a/lib/Analysis/LoopInfo.cpp +++ b/lib/Analysis/LoopInfo.cpp @@ -276,6 +276,30 @@ bool Loop::isLCSSAForm() const { return true; } + +/// isLoopSimplifyForm - Return true if the Loop is in the form that +/// the LoopSimplify form transforms loops to, which is sometimes called +/// normal form. +bool Loop::isLoopSimplifyForm() const { + // Normal-form loops have a preheader. + if (!getLoopPreheader()) + return false; + // Normal-form loops have a single backedge. + if (!getLoopLatch()) + return false; + // Each predecessor of each exit block of a normal loop is contained + // within the loop. + SmallVector ExitBlocks; + getExitBlocks(ExitBlocks); + for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) + for (pred_iterator PI = pred_begin(ExitBlocks[i]), + PE = pred_end(ExitBlocks[i]); PI != PE; ++PI) + if (!contains(*PI)) + return false; + // All the requirements are met. + return true; +} + //===----------------------------------------------------------------------===// // LoopInfo implementation //