From afc3ae30c834b8f519c87bf8c47fc7c96657fda7 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Thu, 16 Jul 2009 16:16:23 +0000 Subject: Add an isLoopSimplifyForm() predicate, following the example of isLCSSAForm(), to test whether a loop is in the form guaranteed by the LoopSimplify pass. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76077 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/LoopInfo.cpp | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'lib/Analysis') diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp index 63de1aa..d350fa6 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 // -- cgit v1.1