[llvm-mca] Move llvm-mca library to llvm/lib/MCA.
Summary: See PR38731.
Reviewers: andreadb
Subscribers: mgorny, javed.absar, tschuett, gbedwell, andreadb, RKSimon, llvm-commits
Differential Revision: https://reviews.llvm.org/D55557
llvm-svn: 349332
diff --git a/llvm/lib/MCA/Support.cpp b/llvm/lib/MCA/Support.cpp
new file mode 100644
index 0000000..3271bc6
--- /dev/null
+++ b/llvm/lib/MCA/Support.cpp
@@ -0,0 +1,79 @@
+//===--------------------- Support.cpp --------------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// This file implements a few helper functions used by various pipeline
+/// components.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MCA/Support.h"
+#include "llvm/MC/MCSchedule.h"
+
+namespace llvm {
+namespace mca {
+
+void computeProcResourceMasks(const MCSchedModel &SM,
+ SmallVectorImpl<uint64_t> &Masks) {
+ unsigned ProcResourceID = 0;
+
+ // Create a unique bitmask for every processor resource unit.
+ // Skip resource at index 0, since it always references 'InvalidUnit'.
+ Masks.resize(SM.getNumProcResourceKinds());
+ for (unsigned I = 1, E = SM.getNumProcResourceKinds(); I < E; ++I) {
+ const MCProcResourceDesc &Desc = *SM.getProcResource(I);
+ if (Desc.SubUnitsIdxBegin)
+ continue;
+ Masks[I] = 1ULL << ProcResourceID;
+ ProcResourceID++;
+ }
+
+ // Create a unique bitmask for every processor resource group.
+ for (unsigned I = 1, E = SM.getNumProcResourceKinds(); I < E; ++I) {
+ const MCProcResourceDesc &Desc = *SM.getProcResource(I);
+ if (!Desc.SubUnitsIdxBegin)
+ continue;
+ Masks[I] = 1ULL << ProcResourceID;
+ for (unsigned U = 0; U < Desc.NumUnits; ++U) {
+ uint64_t OtherMask = Masks[Desc.SubUnitsIdxBegin[U]];
+ Masks[I] |= OtherMask;
+ }
+ ProcResourceID++;
+ }
+}
+
+double computeBlockRThroughput(const MCSchedModel &SM, unsigned DispatchWidth,
+ unsigned NumMicroOps,
+ ArrayRef<unsigned> ProcResourceUsage) {
+ // The block throughput is bounded from above by the hardware dispatch
+ // throughput. That is because the DispatchWidth is an upper bound on the
+ // number of opcodes that can be part of a single dispatch group.
+ double Max = static_cast<double>(NumMicroOps) / DispatchWidth;
+
+ // The block throughput is also limited by the amount of hardware parallelism.
+ // The number of available resource units affects the resource pressure
+ // distribution, as well as how many blocks can be executed every cycle.
+ for (unsigned I = 0, E = SM.getNumProcResourceKinds(); I < E; ++I) {
+ unsigned ResourceCycles = ProcResourceUsage[I];
+ if (!ResourceCycles)
+ continue;
+
+ const MCProcResourceDesc &MCDesc = *SM.getProcResource(I);
+ double Throughput = static_cast<double>(ResourceCycles) / MCDesc.NumUnits;
+ Max = std::max(Max, Throughput);
+ }
+
+ // The block reciprocal throughput is computed as the MAX of:
+ // - (NumMicroOps / DispatchWidth)
+ // - (NumUnits / ResourceCycles) for every consumed processor resource.
+ return Max;
+}
+
+} // namespace mca
+} // namespace llvm