From de28bdadff78ceea6bb05e23dc3b4cc92fa359ed Mon Sep 17 00:00:00 2001
From: Tom Stellard <thomas.stellard@amd.com>
Date: Thu, 10 Oct 2013 17:11:12 +0000
Subject: R600: Use StructurizeCFGPass for non SI targets

StructurizeCFG pass allows to make complex cfg reducible ; it allows a lot of
shader from shadertoy (which exhibits complex control flow constructs) to works
correctly with respect to CFG handling (and allow us to detect potential bug in
other part of the backend).

We provide a cmd line argument to disable the pass for debug purpose.

Patch by: Vincent Lejeune

Reviewed-by: Tom Stellard <thomas.stellard@amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192363 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/R600/AMDGPU.td                 | 5 +++++
 lib/Target/R600/AMDGPUSubtarget.cpp       | 5 +++++
 lib/Target/R600/AMDGPUSubtarget.h         | 2 ++
 lib/Target/R600/AMDGPUTargetMachine.cpp   | 5 ++++-
 lib/Target/R600/R600EmitClauseMarkers.cpp | 1 +
 lib/Target/R600/R600Packetizer.cpp        | 2 +-
 6 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/lib/Target/R600/AMDGPU.td b/lib/Target/R600/AMDGPU.td
index 0048e25..a722f55 100644
--- a/lib/Target/R600/AMDGPU.td
+++ b/lib/Target/R600/AMDGPU.td
@@ -21,6 +21,11 @@ def FeatureDumpCode : SubtargetFeature <"DumpCode",
         "true",
         "Dump MachineInstrs in the CodeEmitter">;
 
+def FeatureIRStructurizer : SubtargetFeature <"EnableIRStructurizer",
+        "EnableIRStructurizer",
+        "true",
+        "Enable IR Structurizer">;
+
 // Target features
 
 def FeatureFP64     : SubtargetFeature<"fp64",
diff --git a/lib/Target/R600/AMDGPUSubtarget.cpp b/lib/Target/R600/AMDGPUSubtarget.cpp
index 53cfe84..1e21c8e 100644
--- a/lib/Target/R600/AMDGPUSubtarget.cpp
+++ b/lib/Target/R600/AMDGPUSubtarget.cpp
@@ -36,6 +36,7 @@ AMDGPUSubtarget::AMDGPUSubtarget(StringRef TT, StringRef CPU, StringRef FS) :
   Gen = AMDGPUSubtarget::R600;
   FP64 = false;
   CaymanISA = false;
+  EnableIRStructurizer = false;
   ParseSubtargetFeatures(GPU, FS);
   DevName = GPU;
 }
@@ -65,6 +66,10 @@ AMDGPUSubtarget::hasCaymanISA() const {
   return CaymanISA;
 }
 bool
+AMDGPUSubtarget::IsIRStructurizerEnabled() const {
+  return EnableIRStructurizer;
+}
+bool
 AMDGPUSubtarget::isTargetELF() const {
   return false;
 }
diff --git a/lib/Target/R600/AMDGPUSubtarget.h b/lib/Target/R600/AMDGPUSubtarget.h
index 0e8b58a..c5345cc 100644
--- a/lib/Target/R600/AMDGPUSubtarget.h
+++ b/lib/Target/R600/AMDGPUSubtarget.h
@@ -48,6 +48,7 @@ private:
   enum Generation Gen;
   bool FP64;
   bool CaymanISA;
+  bool EnableIRStructurizer;
 
   InstrItineraryData InstrItins;
 
@@ -63,6 +64,7 @@ public:
   enum Generation getGeneration() const;
   bool hasHWFP64() const;
   bool hasCaymanISA() const;
+  bool IsIRStructurizerEnabled() const;
 
   virtual bool enableMachineScheduler() const {
     return getGeneration() <= NORTHERN_ISLANDS;
diff --git a/lib/Target/R600/AMDGPUTargetMachine.cpp b/lib/Target/R600/AMDGPUTargetMachine.cpp
index 66585e4..1fef0b1 100644
--- a/lib/Target/R600/AMDGPUTargetMachine.cpp
+++ b/lib/Target/R600/AMDGPUTargetMachine.cpp
@@ -33,6 +33,7 @@
 #include "llvm/Transforms/Scalar.h"
 #include <llvm/CodeGen/Passes.h>
 
+
 using namespace llvm;
 
 extern "C" void LLVMInitializeR600Target() {
@@ -123,9 +124,11 @@ bool
 AMDGPUPassConfig::addPreISel() {
   const AMDGPUSubtarget &ST = TM->getSubtarget<AMDGPUSubtarget>();
   addPass(createFlattenCFGPass());
+  if (ST.IsIRStructurizerEnabled() ||
+      ST.getGeneration() > AMDGPUSubtarget::NORTHERN_ISLANDS)
+    addPass(createStructurizeCFGPass());
   if (ST.getGeneration() > AMDGPUSubtarget::NORTHERN_ISLANDS) {
     addPass(createSITypeRewriter());
-    addPass(createStructurizeCFGPass());
     addPass(createSIAnnotateControlFlowPass());
   } else {
     addPass(createR600TextureIntrinsicsReplacer());
diff --git a/lib/Target/R600/R600EmitClauseMarkers.cpp b/lib/Target/R600/R600EmitClauseMarkers.cpp
index beacc0e..928c0e3 100644
--- a/lib/Target/R600/R600EmitClauseMarkers.cpp
+++ b/lib/Target/R600/R600EmitClauseMarkers.cpp
@@ -84,6 +84,7 @@ private:
     switch (MI->getOpcode()) {
     case AMDGPU::KILL:
     case AMDGPU::RETURN:
+    case AMDGPU::IMPLICIT_DEF:
       return true;
     default:
       return false;
diff --git a/lib/Target/R600/R600Packetizer.cpp b/lib/Target/R600/R600Packetizer.cpp
index bed9115..03d8d87 100644
--- a/lib/Target/R600/R600Packetizer.cpp
+++ b/lib/Target/R600/R600Packetizer.cpp
@@ -340,7 +340,7 @@ bool R600Packetizer::runOnMachineFunction(MachineFunction &Fn) {
     MachineBasicBlock::iterator End = MBB->end();
     MachineBasicBlock::iterator MI = MBB->begin();
     while (MI != End) {
-      if (MI->isKill() ||
+      if (MI->isKill() || MI->getOpcode() == AMDGPU::IMPLICIT_DEF ||
           (MI->getOpcode() == AMDGPU::CF_ALU && !MI->getOperand(8).getImm())) {
         MachineBasicBlock::iterator DeleteMI = MI;
         ++MI;
-- 
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