[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, 9 insertions, 3 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
index 12e90cc7732..4c23beef616 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
@@ -278,11 +278,14 @@ void AMDGPUAsmPrinter::emitCommonFunctionComments(
   uint32_t NumVGPR,
   uint32_t NumSGPR,
   uint64_t ScratchSize,
-  uint64_t CodeSize) {
+  uint64_t CodeSize,
+  const AMDGPUMachineFunction *MFI) {
   OutStreamer->emitRawComment(" codeLenInByte = " + Twine(CodeSize), false);
   OutStreamer->emitRawComment(" NumSgprs: " + Twine(NumSGPR), false);
   OutStreamer->emitRawComment(" NumVgprs: " + Twine(NumVGPR), false);
   OutStreamer->emitRawComment(" ScratchSize: " + Twine(ScratchSize), false);
+  OutStreamer->emitRawComment(" MemoryBound: " + Twine(MFI->isMemoryBound()),
+                              false);
 }
 
 bool AMDGPUAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
@@ -339,7 +342,7 @@ bool AMDGPUAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
         Info.NumVGPR,
         Info.getTotalNumSGPRs(MF.getSubtarget<SISubtarget>()),
         Info.PrivateSegmentSize,
-        getFunctionCodeSize(MF));
+        getFunctionCodeSize(MF), MFI);
       return false;
     }
 
@@ -347,7 +350,7 @@ bool AMDGPUAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
     emitCommonFunctionComments(CurrentProgramInfo.NumVGPR,
                                CurrentProgramInfo.NumSGPR,
                                CurrentProgramInfo.ScratchSize,
-                               getFunctionCodeSize(MF));
+                               getFunctionCodeSize(MF), MFI);
 
     OutStreamer->emitRawComment(
       " FloatMode: " + Twine(CurrentProgramInfo.FloatMode), false);
@@ -376,6 +379,9 @@ bool AMDGPUAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
       " ReservedVGPRCount: " + Twine(CurrentProgramInfo.ReservedVGPRCount),
       false);
 
+    OutStreamer->emitRawComment(
+      " WaveLimiterHint : " + Twine(MFI->needsWaveLimiter()), false);
+
     if (MF.getSubtarget<SISubtarget>().debuggerEmitPrologue()) {
       OutStreamer->emitRawComment(
         " DebuggerWavefrontPrivateSegmentOffsetSGPR: s" +