1 files changed, 82 insertions, 0 deletions
diff --git a/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp b/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
new file mode 100644
index 00000000000..6dacc742b12
--- /dev/null
+++ b/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
@@ -0,0 +1,82 @@
+//===-- AMDGPUTargetTransformInfo.cpp - AMDGPU specific TTI pass ---------===//
+//
+//                     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 TargetTransformInfo analysis pass specific to the
+// AMDGPU target machine. It uses the target's detailed information to provide
+// more precise answers to certain TTI queries, while letting the target
+// independent and default TTI implementations handle the rest.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AMDGPUTargetTransformInfo.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/CodeGen/BasicTTIImpl.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Target/CostTable.h"
+#include "llvm/Target/TargetLowering.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "AMDGPUtti"
+
+void AMDGPUTTIImpl::getUnrollingPreferences(Loop *L,
+                                            TTI::UnrollingPreferences &UP) {
+  UP.Threshold = 300; // Twice the default.
+  UP.MaxCount = UINT_MAX;
+  UP.Partial = true;
+
+  // TODO: Do we want runtime unrolling?
+
+  for (const BasicBlock *BB : L->getBlocks()) {
+    const DataLayout &DL = BB->getModule()->getDataLayout();
+    for (const Instruction &I : *BB) {
+      const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&I);
+      if (!GEP || GEP->getAddressSpace() != AMDGPUAS::PRIVATE_ADDRESS)
+        continue;
+
+      const Value *Ptr = GEP->getPointerOperand();
+      const AllocaInst *Alloca =
+          dyn_cast<AllocaInst>(GetUnderlyingObject(Ptr, DL));
+      if (Alloca) {
+        // We want to do whatever we can to limit the number of alloca
+        // instructions that make it through to the code generator.  allocas
+        // require us to use indirect addressing, which is slow and prone to
+        // compiler bugs.  If this loop does an address calculation on an
+        // alloca ptr, then we want to use a higher than normal loop unroll
+        // threshold. This will give SROA a better chance to eliminate these
+        // allocas.
+        //
+        // Don't use the maximum allowed value here as it will make some
+        // programs way too big.
+        UP.Threshold = 800;
+      }
+    }
+  }
+}
+
+unsigned AMDGPUTTIImpl::getNumberOfRegisters(bool Vec) {
+  if (Vec)
+    return 0;
+
+  // Number of VGPRs on SI.
+  if (ST->getGeneration() >= AMDGPUSubtarget::SOUTHERN_ISLANDS)
+    return 256;
+
+  return 4 * 128; // XXX - 4 channels. Should these count as vector instead?
+}
+
+unsigned AMDGPUTTIImpl::getRegisterBitWidth(bool) { return 32; }
+
+unsigned AMDGPUTTIImpl::getMaxInterleaveFactor(unsigned VF) {
+  // Semi-arbitrary large amount.
+  return 64;
+}