From 7c7aba6e5fef47a01a136be655b0a92cfd7090f6 Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Fri, 16 Jun 2017 21:03:24 +0000 Subject: Vendor import of llvm trunk r305575: https://llvm.org/svn/llvm-project/llvm/trunk@305575 --- lib/CodeGen/MachineLICM.cpp | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'lib/CodeGen/MachineLICM.cpp') diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp index 52d5819f8dbc..c7113f1fdc47 100644 --- a/lib/CodeGen/MachineLICM.cpp +++ b/lib/CodeGen/MachineLICM.cpp @@ -895,8 +895,11 @@ bool MachineLICM::IsLoopInvariantInst(MachineInstr &I) { // If the physreg has no defs anywhere, it's just an ambient register // and we can freely move its uses. Alternatively, if it's allocatable, // it could get allocated to something with a def during allocation. - if (!MRI->isConstantPhysReg(Reg)) - return false; + // However, if the physreg is known to always be caller saved/restored + // then this use is safe to hoist. + if (!MRI->isConstantPhysReg(Reg) && + !(TRI->isCallerPreservedPhysReg(Reg, *I.getParent()->getParent()))) + return false; // Otherwise it's safe to move. continue; } else if (!MO.isDead()) { -- cgit v1.3