From 8ad916fe915734219a4bfbb79fb6d6e0b424a2ae Mon Sep 17 00:00:00 2001
From: Krzysztof Parzyszek <kparzysz@codeaurora.org>
Date: Wed, 16 Dec 2015 16:38:16 +0000
Subject: [PATCH] [Packetizer] Add a check whether an instruction should be
packetized now
Add a function VLIWPacketizerList::shouldAddToPacket, which will allow
specific implementations to decide if it is profitable to add given
instruction to the current packet.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255780 91177308-0d34-0410-b5e6-96231b3b80d8
---
include/llvm/CodeGen/DFAPacketizer.h | 10 ++++++++++
lib/CodeGen/DFAPacketizer.cpp | 5 +++--
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/llvm/CodeGen/DFAPacketizer.h b/include/llvm/CodeGen/DFAPacketizer.h
index 11d959b2e7f..40ec201107e 100644
--- a/include/llvm/CodeGen/DFAPacketizer.h
+++ b/include/llvm/CodeGen/DFAPacketizer.h
@@ -186,6 +186,16 @@ public:
return true;
}
+ // Check if the packetizer should try to add the given instruction to
+ // the current packet. One reasons for which it may not be desirable
+ // to include an instruction in the current packet could be that it
+ // would cause a stall.
+ // If this function returns "false", the current packet will be ended,
+ // and the instruction will be added to the next packet.
+ virtual bool shouldAddToPacket(const MachineInstr *MI) {
+ return true;
+ }
+
// isLegalToPacketizeTogether - Is it legal to packetize SUI and SUJ
// together.
virtual bool isLegalToPacketizeTogether(SUnit *SUI, SUnit *SUJ) {
diff --git a/lib/CodeGen/DFAPacketizer.cpp b/lib/CodeGen/DFAPacketizer.cpp
index 80e03d985d5..af6b6a392b7 100644
--- a/lib/CodeGen/DFAPacketizer.cpp
+++ b/lib/CodeGen/DFAPacketizer.cpp
@@ -239,7 +239,7 @@ void VLIWPacketizerList::PacketizeMIs(MachineBasicBlock *MBB,
// Ask DFA if machine resource is available for MI.
bool ResourceAvail = ResourceTracker->canReserveResources(MI);
- if (ResourceAvail) {
+ if (ResourceAvail && shouldAddToPacket(MI)) {
// Dependency check for MI with instructions in CurrentPacketMIs.
for (std::vector<MachineInstr*>::iterator VI = CurrentPacketMIs.begin(),
VE = CurrentPacketMIs.end(); VI != VE; ++VI) {
@@ -258,7 +258,8 @@ void VLIWPacketizerList::PacketizeMIs(MachineBasicBlock *MBB,
} // !isLegalToPacketizeTogether.
} // For all instructions in CurrentPacketMIs.
} else {
- // End the packet if resource is not available.
+ // End the packet if resource is not available, or if the instruction
+ // shoud not be added to the current packet.
endPacket(MBB, MI);
}
--
2.40.0