From 1a37d7e807ad6cc71fe3cffdf6674644c46a60eb Mon Sep 17 00:00:00 2001 From: Sebastian Pop Date: Tue, 25 Sep 2012 20:35:36 +0000 Subject: TargetLowering interface to set/get minimum block entries for jump tables. Provide interface in TargetLowering to set or get the minimum number of basic blocks whereby jump tables are generated for switch statements rather than an if sequence. getMinimumJumpTableEntries() defaults to 4. setMinimumJumpTableEntries() allows target configuration. This patch changes the default for the Hexagon architecture to 5 as it improves performance on some benchmarks. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164628 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp') diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index 483b051bdc..f71c8b81cb 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -2093,7 +2093,7 @@ bool SelectionDAGBuilder::handleJTSwitchCase(CaseRec &CR, for (CaseItr I = CR.Range.first, E = CR.Range.second; I != E; ++I) TSize += I->size(); - if (!areJTsAllowed(TLI) || TSize.ult(4)) + if (!areJTsAllowed(TLI) || TSize.ult(TLI.getMinimumJumpTableEntries())) return false; APInt Range = ComputeRange(First, Last); @@ -2565,9 +2565,10 @@ void SelectionDAGBuilder::visitSwitch(const SwitchInst &SI) { if (handleSmallSwitchRange(CR, WorkList, SV, Default, SwitchMBB)) continue; - // If the switch has more than 5 blocks, and at least 40% dense, and the + // If the switch has more than N blocks, and is at least 40% dense, and the // target supports indirect branches, then emit a jump table rather than // lowering the switch to a binary tree of conditional branches. + // N defaults to 4 and is controlled via TLS.getMinimumJumpTableEntries(). if (handleJTSwitchCase(CR, WorkList, SV, Default, SwitchMBB)) continue; -- cgit v1.2.3-70-g09d2