From d493b34d31ddb37b2e2f0b24e00c4597cb1dcfd6 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sat, 9 Apr 2005 15:23:25 +0000 Subject: [PATCH] Consider the livein/out set for a function, allowing targets to not have to use ugly imp_def/imp_uses for arguments and return values. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21180 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/LiveVariables.cpp | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp index 80316102601..175b5fd7c16 100644 --- a/lib/CodeGen/LiveVariables.cpp +++ b/lib/CodeGen/LiveVariables.cpp @@ -163,6 +163,14 @@ bool LiveVariables::runOnMachineFunction(MachineFunction &MF) { /// Get some space for a respectable number of registers... VirtRegInfo.resize(64); + + // Mark live-in registers as live-in. + for (MachineFunction::liveinout_iterator I = MF.livein_begin(), + E = MF.livein_end(); I != E; ++I) { + assert(MRegisterInfo::isPhysicalRegister(*I) && + "Cannot have a live-in virtual register!"); + HandlePhysRegDef(*I, 0); + } // Calculate live variable information in depth first order on the CFG of the // function. This guarantees that we will see the definition of a virtual @@ -260,6 +268,18 @@ bool LiveVariables::runOnMachineFunction(MachineFunction &MF) { } } + // Finally, if the last block in the function is a return, make sure to mark + // it as using all of the live-out values in the function. + if (!MBB->empty() && TII.isReturn(MBB->back().getOpcode())) { + MachineInstr *Ret = &MBB->back(); + for (MachineFunction::liveinout_iterator I = MF.liveout_begin(), + E = MF.liveout_end(); I != E; ++I) { + assert(MRegisterInfo::isPhysicalRegister(*I) && + "Cannot have a live-in virtual register!"); + HandlePhysRegUse(*I, Ret); + } + } + // Loop over PhysRegInfo, killing any registers that are available at the // end of the basic block. This also resets the PhysRegInfo map. for (unsigned i = 0, e = RegInfo->getNumRegs(); i != e; ++i) -- 2.34.1