From daa2bf9a192496a456b548fbb6787cdcee183c70 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 28 Jun 2006 16:38:55 +0000 Subject: [PATCH] Don't unswitch really large loops even if they are mostly filled with empty blocks. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28959 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/LoopUnswitch.cpp | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp index d33dcb7c0b0..945803f0afc 100644 --- a/lib/Transforms/Scalar/LoopUnswitch.cpp +++ b/lib/Transforms/Scalar/LoopUnswitch.cpp @@ -333,6 +333,12 @@ unsigned LoopUnswitch::getLoopUnswitchCost(Loop *L, Value *LIC) { if (IsTrivialUnswitchCondition(L, LIC)) return 0; + // If the loop is really large (over twice our threshold) don't even consider + // unswitching it. This will produce a really large loop with lots of empty + // blocks. + if (L->getBlocks().size() > 2*Threshold) + return 2*Threshold; + unsigned Cost = 0; // FIXME: this is brain dead. It should take into consideration code // shrinkage. -- 2.34.1