From de5fa932b9bc0eebe803c9549586bf512eeb12f9 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Wed, 27 Oct 2010 23:17:17 +0000 Subject: [PATCH] Putting r117193 back except for the compile time cost. Rather than assuming fallthroughs uses all registers, just gather the union of all successor liveins. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117506 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/ScheduleDAGInstrs.cpp | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/lib/CodeGen/ScheduleDAGInstrs.cpp b/lib/CodeGen/ScheduleDAGInstrs.cpp index 9b5d13b1200..abd68caf122 100644 --- a/lib/CodeGen/ScheduleDAGInstrs.cpp +++ b/lib/CodeGen/ScheduleDAGInstrs.cpp @@ -168,9 +168,16 @@ void ScheduleDAGInstrs::AddSchedBarrierDeps() { } } else { // For others, e.g. fallthrough, conditional branch, assume the exit - // uses all the registers. - // FIXME: This causes too much compile time regression. We need to compute - // liveout instead. + // uses all the registers that are livein to the successor blocks. + SmallSet Seen; + for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(), + SE = BB->succ_end(); SI != SE; ++SI) + for (MachineBasicBlock::livein_iterator I = (*SI)->livein_begin(), + E = (*SI)->livein_end(); I != E; ++I) { + unsigned Reg = *I; + if (Seen.insert(Reg)) + Uses[Reg].push_back(&ExitSU); + } } } -- 2.34.1