From 5b2c4dc5f8f70352f029d595797089821eb39b3c Mon Sep 17 00:00:00 2001 From: Nadav Rotem Date: Wed, 31 Oct 2012 03:31:07 +0000 Subject: LoopVectorize: Do not vectorize loops with tiny constant trip counts. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167101 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Vectorize/LoopVectorize.cpp | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'lib/Transforms/Vectorize/LoopVectorize.cpp') diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp index e82dfa2..fd728bd 100644 --- a/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -1145,6 +1145,14 @@ bool LoopVectorizationLegality::canVectorize() { return false; } + // Do not loop-vectorize loops with a tiny trip count. + unsigned TC = SE->getSmallConstantTripCount(TheLoop, BB); + if (TC > 0 && TC < 16) { + DEBUG(dbgs() << "LV: Found a loop with a very small trip count. " << + "This loop is not worth vectorizing.\n"); + return false; + } + DEBUG(dbgs() << "LV: We can vectorize this loop!\n"); // Okay! We can vectorize. At this point we don't have any other mem analysis -- cgit v1.1