From 80799fbe3c048cc78aba59c389e4b33e936bc190 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Tue, 27 Mar 2012 17:06:09 +0000 Subject: Branch folding may invalidate liveness. Branch folding can use a register scavenger to update liveness information when required. Don't do that if liveness information is already invalid. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153517 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/BranchFolding.cpp | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'lib/CodeGen') diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp index f57f4a8e28..ef1d2baed9 100644 --- a/lib/CodeGen/BranchFolding.cpp +++ b/lib/CodeGen/BranchFolding.cpp @@ -23,6 +23,7 @@ #include "llvm/CodeGen/MachineModuleInfo.h" #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineJumpTableInfo.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/RegisterScavenging.h" #include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetMachine.h" @@ -183,8 +184,14 @@ bool BranchFolder::OptimizeFunction(MachineFunction &MF, TII = tii; TRI = tri; MMI = mmi; - - RS = TRI->requiresRegisterScavenging(MF) ? new RegScavenger() : NULL; + RS = NULL; + + // Use a RegScavenger to help update liveness when required. + MachineRegisterInfo &MRI = MF.getRegInfo(); + if (MRI.tracksLiveness() && TRI->requiresRegisterScavenging(MF)) + RS = new RegScavenger(); + else + MRI.invalidateLiveness(); // Fix CFG. The later algorithms expect it to be right. bool MadeChange = false; -- cgit v1.2.3