[llvm] TargetSchedule: factor out code in computeOperandLatency (NFC) (PR #73769)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon updated https://github.com/llvm/llvm-project/pull/73769

>From 997fa13eb0b347bf837967fe1de02f4866ec7bc6 Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <Ramkumar.Ramachandra at imgtec.com>
Date: Tue, 28 Nov 2023 13:29:45 +0000
Subject: [PATCH 1/2] TargetSchedule: factor out code in computeOperandLatency
 (NFC)

Factor out DefaultDefLatency and InstrLatency in computeOperandLatency.
---
 llvm/lib/CodeGen/TargetSchedule.cpp | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/llvm/lib/CodeGen/TargetSchedule.cpp b/llvm/lib/CodeGen/TargetSchedule.cpp
index 3cedb38de2ad8d9..a56e61149e26499 100644
--- a/llvm/lib/CodeGen/TargetSchedule.cpp
+++ b/llvm/lib/CodeGen/TargetSchedule.cpp
@@ -173,8 +173,11 @@ unsigned TargetSchedModel::computeOperandLatency(
   const MachineInstr *DefMI, unsigned DefOperIdx,
   const MachineInstr *UseMI, unsigned UseOperIdx) const {
 
+  unsigned InstrLatency = computeInstrLatency(DefMI);
+  unsigned DefaultDefLatency = TII->defaultDefLatency(SchedModel, *DefMI);
+
   if (!hasInstrSchedModel() && !hasInstrItineraries())
-    return TII->defaultDefLatency(SchedModel, *DefMI);
+    return InstrLatency;
 
   if (hasInstrItineraries()) {
     int OperLatency = 0;
@@ -186,21 +189,16 @@ unsigned TargetSchedModel::computeOperandLatency(
       unsigned DefClass = DefMI->getDesc().getSchedClass();
       OperLatency = InstrItins.getOperandCycle(DefClass, DefOperIdx);
     }
-    if (OperLatency >= 0)
-      return OperLatency;
-
-    // No operand latency was found.
-    unsigned InstrLatency = TII->getInstrLatency(&InstrItins, *DefMI);
 
     // Expected latency is the max of the stage latency and itinerary props.
     // Rather than directly querying InstrItins stage latency, we call a TII
     // hook to allow subtargets to specialize latency. This hook is only
     // applicable to the InstrItins model. InstrSchedModel should model all
     // special cases without TII hooks.
-    InstrLatency =
-        std::max(InstrLatency, TII->defaultDefLatency(SchedModel, *DefMI));
-    return InstrLatency;
+    return OperLatency >= 0 ? OperLatency
+                            : std::max(InstrLatency, DefaultDefLatency);
   }
+
   // hasInstrSchedModel()
   const MCSchedClassDesc *SCDesc = resolveSchedClass(DefMI);
   unsigned DefIdx = findDefIdx(DefMI, DefOperIdx);
@@ -237,7 +235,7 @@ unsigned TargetSchedModel::computeOperandLatency(
   // FIXME: Automatically giving all implicit defs defaultDefLatency is
   // undesirable. We should only do it for defs that are known to the MC
   // desc like flags. Truly implicit defs should get 1 cycle latency.
-  return DefMI->isTransient() ? 0 : TII->defaultDefLatency(SchedModel, *DefMI);
+  return DefMI->isTransient() ? 0 : DefaultDefLatency;
 }
 
 unsigned

>From 741abd61f9e1e9a3a42fbe1aa0683be29dc251dd Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <r at artagnon.com>
Date: Thu, 30 Nov 2023 09:51:27 +0000
Subject: [PATCH 2/2] Update llvm/lib/CodeGen/TargetSchedule.cpp

Co-authored-by: Francesco Petrogalli <francesco.petrogalli at apple.com>
---
 llvm/lib/CodeGen/TargetSchedule.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/CodeGen/TargetSchedule.cpp b/llvm/lib/CodeGen/TargetSchedule.cpp
index a56e61149e26499..606d59997c93bdd 100644
--- a/llvm/lib/CodeGen/TargetSchedule.cpp
+++ b/llvm/lib/CodeGen/TargetSchedule.cpp
@@ -173,8 +173,8 @@ unsigned TargetSchedModel::computeOperandLatency(
   const MachineInstr *DefMI, unsigned DefOperIdx,
   const MachineInstr *UseMI, unsigned UseOperIdx) const {
 
-  unsigned InstrLatency = computeInstrLatency(DefMI);
-  unsigned DefaultDefLatency = TII->defaultDefLatency(SchedModel, *DefMI);
+  const unsigned InstrLatency = computeInstrLatency(DefMI);
+  const unsigned DefaultDefLatency = TII->defaultDefLatency(SchedModel, *DefMI);
 
   if (!hasInstrSchedModel() && !hasInstrItineraries())
     return InstrLatency;