From 1a8f36e3ce5b9c230781b66600c81536128abfb5 Mon Sep 17 00:00:00 2001
From: David Goodwin <david_goodwin@apple.com>
Date: Wed, 12 Aug 2009 18:31:53 +0000
Subject: Enhance the InstrStage object to enable the specification of an
 Itinerary with overlapping stages. The default is to maintain the current
 behavior that the "next" stage immediately follows the previous one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78827 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/ExactHazardRecognizer.cpp | 54 ++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 29 deletions(-)

(limited to 'lib/CodeGen/ExactHazardRecognizer.cpp')

diff --git a/lib/CodeGen/ExactHazardRecognizer.cpp b/lib/CodeGen/ExactHazardRecognizer.cpp
index 48043f286c..8bac08a4a0 100644
--- a/lib/CodeGen/ExactHazardRecognizer.cpp
+++ b/lib/CodeGen/ExactHazardRecognizer.cpp
@@ -34,12 +34,12 @@ ExactHazardRecognizer::ExactHazardRecognizer(const InstrItineraryData &LItinData
       // If the begin stage of an itinerary has 0 cycles and units,
       // then we have reached the end of the itineraries.
       const InstrStage *IS = ItinData.begin(idx), *E = ItinData.end(idx);
-      if ((IS->Cycles == 0) && (IS->Units == 0))
+      if ((IS->getCycles() == 0) && (IS->getUnits() == 0))
         break;
 
       unsigned ItinDepth = 0;
       for (; IS != E; ++IS)
-        ItinDepth += std::max(1U, IS->Cycles);
+        ItinDepth += IS->getCycles();
 
       ScoreboardDepth = std::max(ScoreboardDepth, ItinDepth);
     }
@@ -89,27 +89,25 @@ ExactHazardRecognizer::HazardType ExactHazardRecognizer::getHazardType(SUnit *SU
   unsigned idx = SU->getInstr()->getDesc().getSchedClass();
   for (const InstrStage *IS = ItinData.begin(idx), *E = ItinData.end(idx);
        IS != E; ++IS) {
-    // If the stages cycles are 0, then we must have the FU free in
-    // the current cycle, but we don't advance the cycle time .
-    unsigned StageCycles = std::max(1U, IS->Cycles);
-
     // We must find one of the stage's units free for every cycle the
-    // stage is occupied.
-    for (unsigned int i = 0; i < StageCycles; ++i) {
-      assert((cycle < ScoreboardDepth) && "Scoreboard depth exceeded!");
-
-      unsigned index = getFutureIndex(cycle);
-      unsigned freeUnits = IS->Units & ~Scoreboard[index];
+    // stage is occupied. FIXME it would be more accurate to find the
+    // same unit free in all the cycles.
+    for (unsigned int i = 0; i < IS->getCycles(); ++i) {
+      assert(((cycle + i) < ScoreboardDepth) && 
+             "Scoreboard depth exceeded!");
+
+      unsigned index = getFutureIndex(cycle + i);
+      unsigned freeUnits = IS->getUnits() & ~Scoreboard[index];
       if (!freeUnits) {
-        DEBUG(errs() << "*** Hazard in cycle " << cycle << ", ");
+        DEBUG(errs() << "*** Hazard in cycle " << (cycle + i) << ", ");
         DEBUG(errs() << "SU(" << SU->NodeNum << "): ");
         DEBUG(SU->getInstr()->dump());
         return Hazard;
       }
-
-      if (IS->Cycles > 0)
-        ++cycle;
     }
+
+    // Advance the cycle to the next stage.
+    cycle += IS->getNextCycles();
   }
 
   return NoHazard;
@@ -123,17 +121,15 @@ void ExactHazardRecognizer::EmitInstruction(SUnit *SU) {
   unsigned idx = SU->getInstr()->getDesc().getSchedClass();
   for (const InstrStage *IS = ItinData.begin(idx), *E = ItinData.end(idx);
        IS != E; ++IS) {
-    // If the stages cycles are 0, then we must reserve the FU in the
-    // current cycle, but we don't advance the cycle time .
-    unsigned StageCycles = std::max(1U, IS->Cycles);
-
     // We must reserve one of the stage's units for every cycle the
-    // stage is occupied.
-    for (unsigned int i = 0; i < StageCycles; ++i) {
-      assert((cycle < ScoreboardDepth) && "Scoreboard depth exceeded!");
-
-      unsigned index = getFutureIndex(cycle);
-      unsigned freeUnits = IS->Units & ~Scoreboard[index];
+    // stage is occupied. FIXME it would be more accurate to reserve
+    // the same unit free in all the cycles.
+    for (unsigned int i = 0; i < IS->getCycles(); ++i) {
+      assert(((cycle + i) < ScoreboardDepth) &&
+             "Scoreboard depth exceeded!");
+
+      unsigned index = getFutureIndex(cycle + i);
+      unsigned freeUnits = IS->getUnits() & ~Scoreboard[index];
       
       // reduce to a single unit
       unsigned freeUnit = 0;
@@ -144,10 +140,10 @@ void ExactHazardRecognizer::EmitInstruction(SUnit *SU) {
 
       assert(freeUnit && "No function unit available!");
       Scoreboard[index] |= freeUnit;
-      
-      if (IS->Cycles > 0)
-        ++cycle;
     }
+
+    // Advance the cycle to the next stage.
+    cycle += IS->getNextCycles();
   }
 
   DEBUG(dumpScoreboard());
-- 
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