[AMDGPU] Add perf hints to functions

This is adoption of HSAIL perfhint pass. Two types of hints are produced:

1. Function is memory bound.
2. Kernel can use wave limiter.

Currently these hints are used in the scheduler. If a function is suspected
to be memory bound we allow occupancy to decrease to 4 waves in the course
of scheduling.

Differential Revision: https://reviews.llvm.org/D46992

llvm-svn: 333289

1 files changed, 13 insertions, 1 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp b/llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp
index b7c8c12..73c073b 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp
@@ -9,6 +9,8 @@
 
 #include "AMDGPUMachineFunction.h"
 #include "AMDGPUSubtarget.h"
+#include "AMDGPUPerfHintAnalysis.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 
 using namespace llvm;
 
@@ -20,9 +22,19 @@ AMDGPUMachineFunction::AMDGPUMachineFunction(const MachineFunction &MF) :
   LDSSize(0),
   ABIArgOffset(0),
   IsEntryFunction(AMDGPU::isEntryFunctionCC(MF.getFunction().getCallingConv())),
-  NoSignedZerosFPMath(MF.getTarget().Options.NoSignedZerosFPMath) {
+  NoSignedZerosFPMath(MF.getTarget().Options.NoSignedZerosFPMath),
+  MemoryBound(false),
+  WaveLimiter(false) {
   // FIXME: Should initialize KernArgSize based on ExplicitKernelArgOffset,
   // except reserved size is not correctly aligned.
+
+  if (auto *Resolver = MF.getMMI().getResolver()) {
+    if (AMDGPUPerfHintAnalysis *PHA = static_cast<AMDGPUPerfHintAnalysis*>(
+          Resolver->getAnalysisIfAvailable(&AMDGPUPerfHintAnalysisID, true))) {
+      MemoryBound = PHA->isMemoryBound(&MF.getFunction());
+      WaveLimiter = PHA->needsWaveLimiter(&MF.getFunction());
+    }
+  }
 }
 
 unsigned AMDGPUMachineFunction::allocateLDSGlobal(const DataLayout &DL,