From 55574c2ceab1b7c4dd1cc47d2fb328bc3728d29c Mon Sep 17 00:00:00 2001 From: Bill Wendling Date: Wed, 20 Feb 2008 19:35:34 +0000 Subject: [PATCH] Improve some comments explaining the "handle kills" stuff better. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47395 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/LiveVariables.cpp | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp index ea27b2e08e0..809048e8ef7 100644 --- a/lib/CodeGen/LiveVariables.cpp +++ b/lib/CodeGen/LiveVariables.cpp @@ -296,6 +296,7 @@ void LiveVariables::addRegisterKills(unsigned Reg, MachineInstr *MI, /// last def/use of the register, or /// - The register has sub-registers and none of them are killed elsewhere. /// +/// SubKills is filled with the set of sub-registers that are killed elsewhere. bool LiveVariables::HandlePhysRegKill(unsigned Reg, const MachineInstr *RefMI, SmallSet &SubKills) { const unsigned *SubRegs = RegInfo->getImmediateSubRegisters(Reg); @@ -320,8 +321,9 @@ bool LiveVariables::HandlePhysRegKill(unsigned Reg, const MachineInstr *RefMI, return false; } -/// HandlePhysRegKill - Calls the recursive version of HandlePhysRegKill. (See -/// above for details.) +/// HandlePhysRegKill - Returns true if the whole register is killed in the +/// machine instruction. If only some of its sub-registers are killed in this +/// machine instruction, then mark those as killed and return false. bool LiveVariables::HandlePhysRegKill(unsigned Reg, MachineInstr *RefMI) { SmallSet SubKills;