From f1e01dcc94fde6b1e184dc799df7145aed34a18b Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Wed, 2 Dec 2009 17:15:24 +0000 Subject: [PATCH] Don't count PHI instructions toward the limit for tail duplicating a block. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90326 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/TailDuplication.cpp | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/lib/CodeGen/TailDuplication.cpp b/lib/CodeGen/TailDuplication.cpp index 9c0b596c33f..a5964585927 100644 --- a/lib/CodeGen/TailDuplication.cpp +++ b/lib/CodeGen/TailDuplication.cpp @@ -129,20 +129,22 @@ bool TailDuplicatePass::TailDuplicate(MachineBasicBlock *TailBB, // Check the instructions in the block to determine whether tail-duplication // is invalid or unlikely to be profitable. - unsigned i = 0; + unsigned InstrCount = 0; bool HasCall = false; for (MachineBasicBlock::iterator I = TailBB->begin(); - I != TailBB->end(); ++I, ++i) { + I != TailBB->end(); ++I) { // Non-duplicable things shouldn't be tail-duplicated. if (I->getDesc().isNotDuplicable()) return false; // Don't duplicate more than the threshold. - if (i == MaxDuplicateCount) return false; + if (InstrCount == MaxDuplicateCount) return false; // Remember if we saw a call. if (I->getDesc().isCall()) HasCall = true; + if (I->getOpcode() != TargetInstrInfo::PHI) + InstrCount += 1; } // Heuristically, don't tail-duplicate calls if it would expand code size, // as it's less likely to be worth the extra cost. - if (i > 1 && HasCall) + if (InstrCount > 1 && HasCall) return false; // Iterate through all the unique predecessors and tail-duplicate this -- 2.34.1