From e057403835c0eac0dccd04f22ce9faafa4c17d4c Mon Sep 17 00:00:00 2001 From: Dale Johannesen Date: Sat, 30 Jan 2010 00:57:47 +0000 Subject: Fix a case where debug_value could affect codegen. llvm-svn: 94866 --- llvm/lib/CodeGen/RegAllocLocal.cpp | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'llvm/lib/CodeGen/RegAllocLocal.cpp') diff --git a/llvm/lib/CodeGen/RegAllocLocal.cpp b/llvm/lib/CodeGen/RegAllocLocal.cpp index cbb5826ce9a..6a09bd98166 100644 --- a/llvm/lib/CodeGen/RegAllocLocal.cpp +++ b/llvm/lib/CodeGen/RegAllocLocal.cpp @@ -838,6 +838,18 @@ void RALocal::AllocateBasicBlock(MachineBasicBlock &MBB) { } } + // If a DEBUG_VALUE says something is located in a spilled register, + // change the DEBUG_VALUE to be undef, which prevents the register + // from being reloaded here. Doing that would change the generated + // code, unless another use immediately follows this instruction. + if (MI->getOpcode()==TargetInstrInfo::DEBUG_VALUE && + MI->getNumOperands()==3 && MI->getOperand(0).isReg()) { + unsigned VirtReg = MI->getOperand(0).getReg(); + if (VirtReg && TargetRegisterInfo::isVirtualRegister(VirtReg) && + !getVirt2PhysRegMapSlot(VirtReg)) + MI->getOperand(0).setReg(0U); + } + // Get the used operands into registers. This has the potential to spill // incoming values if we are out of registers. Note that we completely // ignore physical register uses here. We assume that if an explicit -- cgit v1.2.3