-
-
-void
-MachineSchedInfo::computeIssueGaps(const vector<InstrRUsage>& instrRUForClasses)
-{
- int numOpCodes = mii->getNumRealOpCodes();
- instrRUsages.resize(numOpCodes);
-
- assert(numOpCodes < (1 << MAX_OPCODE_SIZE) - 1
- && "numOpCodes invalid for implementation of class OpCodePair!");
-
- // First, compute issue gaps between pairs of classes based on common
- // resources usages for each class, because most instruction pairs will
- // usually behave the same as their class.
- //
- int classPairGaps[numSchedClasses][numSchedClasses];
- for (InstrSchedClass fromSC=0; fromSC < numSchedClasses; fromSC++)
- for (InstrSchedClass toSC=0; toSC < numSchedClasses; toSC++)
- {
- int classPairGap = ComputeMinGap(instrRUForClasses[fromSC],
- instrRUForClasses[toSC]);
- classPairGaps[fromSC][toSC] = classPairGap;
- }
-
- // Now, for each pair of instructions, use the class pair gap if both
- // instructions have identical resource usage as their respective classes.
- // If not, recompute the gap for the pair from scratch.
-
- longestIssueConflict = 0;
-
- for (MachineOpCode fromOp=0; fromOp < numOpCodes; fromOp++)
- for (MachineOpCode toOp=0; toOp < numOpCodes; toOp++)
- {
- int instrPairGap =
- (instrRUsages[fromOp].sameAsClass && instrRUsages[toOp].sameAsClass)
- ? classPairGaps[getSchedClass(fromOp)][getSchedClass(toOp)]
- : ComputeMinGap(instrRUsages[fromOp], instrRUsages[toOp]);
-
- if (instrPairGap > 0)
- {
- issueGaps[OpCodePair(fromOp,toOp)] = instrPairGap;
- conflictLists[fromOp].push_back(toOp);
- longestIssueConflict = max(longestIssueConflict, instrPairGap);
- }
- }
-}
-
-
-// Check if fromRVec and toRVec have *any* common entries.
-// Assume the vectors are sorted in increasing order.
-// Algorithm copied from function set_intersection() for sorted ranges (stl_algo.h).
-inline static bool
-RUConflict(const vector<resourceId_t>& fromRVec,
- const vector<resourceId_t>& toRVec)
-{
- bool commonElementFound = false;
-
- unsigned fN = fromRVec.size(), tN = toRVec.size();
- unsigned fi = 0, ti = 0;
- while (fi < fN && ti < tN)
- if (fromRVec[fi] < toRVec[ti])
- ++fi;
- else if (toRVec[ti] < fromRVec[fi])
- ++ti;
- else
- {
- commonElementFound = true;
- break;
- }
-
- return commonElementFound;
-}
-
-
-static cycles_t
-ComputeMinGap(const InstrRUsage& fromRU, const InstrRUsage& toRU)
-{
- cycles_t minGap = 0;
-
- if (fromRU.numBubbles > 0)
- minGap = fromRU.numBubbles;
-
- if (minGap < fromRU.numCycles)
- {
- // only need to check from cycle `minGap' onwards
- for (cycles_t gap=minGap; gap <= fromRU.numCycles-1; gap++)
- {
- // check if instr. #2 can start executing `gap' cycles after #1
- // by checking for resource conflicts in each overlapping cycle
- cycles_t numOverlap = min(fromRU.numCycles - gap, toRU.numCycles);
- for (cycles_t c = 0; c <= numOverlap-1; c++)
- if (RUConflict(fromRU.resourcesByCycle[gap + c],
- toRU.resourcesByCycle[c]))
- {// conflict found so minGap must be more than `gap'
- minGap = gap+1;
- break;
- }
- }
- }
-
- return minGap;
-}
-
-//---------------------------------------------------------------------------