[llvm] r199840 - R600: Refactor stack size calculation
Tom Stellard
thomas.stellard at amd.com
Wed Jan 22 13:55:43 PST 2014
Author: tstellar
Date: Wed Jan 22 15:55:43 2014
New Revision: 199840
URL: http://llvm.org/viewvc/llvm-project?rev=199840&view=rev
Log:
R600: Refactor stack size calculation
reviewed-by: Vincent Lejeune <vljn at ovi.com>
Modified:
llvm/trunk/lib/Target/R600/AMDGPUSubtarget.cpp
llvm/trunk/lib/Target/R600/AMDGPUSubtarget.h
llvm/trunk/lib/Target/R600/R600ControlFlowFinalizer.cpp
llvm/trunk/test/CodeGen/R600/elf.r600.ll
Modified: llvm/trunk/lib/Target/R600/AMDGPUSubtarget.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/AMDGPUSubtarget.cpp?rev=199840&r1=199839&r2=199840&view=diff
==============================================================================
--- llvm/trunk/lib/Target/R600/AMDGPUSubtarget.cpp (original)
+++ llvm/trunk/lib/Target/R600/AMDGPUSubtarget.cpp Wed Jan 22 15:55:43 2014
@@ -79,6 +79,23 @@ unsigned
AMDGPUSubtarget::getWavefrontSize() const {
return WavefrontSize;
}
+unsigned
+AMDGPUSubtarget::getStackEntrySize() const {
+ assert(getGeneration() <= NORTHERN_ISLANDS);
+ switch(getWavefrontSize()) {
+ case 16:
+ return 8;
+ case 32:
+ if (hasCaymanISA())
+ return 4;
+ else
+ return 8;
+ case 64:
+ return 4;
+ default:
+ llvm_unreachable("Illegal wavefront size.");
+ }
+}
bool
AMDGPUSubtarget::isTargetELF() const {
return false;
Modified: llvm/trunk/lib/Target/R600/AMDGPUSubtarget.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/AMDGPUSubtarget.h?rev=199840&r1=199839&r2=199840&view=diff
==============================================================================
--- llvm/trunk/lib/Target/R600/AMDGPUSubtarget.h (original)
+++ llvm/trunk/lib/Target/R600/AMDGPUSubtarget.h Wed Jan 22 15:55:43 2014
@@ -70,6 +70,7 @@ public:
bool IsIRStructurizerEnabled() const;
bool isIfCvtEnabled() const;
unsigned getWavefrontSize() const;
+ unsigned getStackEntrySize() const;
virtual bool enableMachineScheduler() const {
return getGeneration() <= NORTHERN_ISLANDS;
Modified: llvm/trunk/lib/Target/R600/R600ControlFlowFinalizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/R600ControlFlowFinalizer.cpp?rev=199840&r1=199839&r2=199840&view=diff
==============================================================================
--- llvm/trunk/lib/Target/R600/R600ControlFlowFinalizer.cpp (original)
+++ llvm/trunk/lib/Target/R600/R600ControlFlowFinalizer.cpp Wed Jan 22 15:55:43 2014
@@ -28,6 +28,134 @@ using namespace llvm;
namespace {
+struct CFStack {
+
+ enum StackItem {
+ ENTRY = 0,
+ SUB_ENTRY = 1,
+ FIRST_NON_WQM_PUSH = 2,
+ FIRST_NON_WQM_PUSH_W_FULL_ENTRY = 3
+ };
+
+ const AMDGPUSubtarget &ST;
+ std::vector<StackItem> BranchStack;
+ std::vector<StackItem> LoopStack;
+ unsigned MaxStackSize;
+ unsigned CurrentEntries;
+ unsigned CurrentSubEntries;
+
+ CFStack(const AMDGPUSubtarget &st, unsigned ShaderType) : ST(st),
+ // We need to reserve a stack entry for CALL_FS in vertex shaders.
+ MaxStackSize(ShaderType == ShaderType::VERTEX ? 1 : 0),
+ CurrentEntries(0), CurrentSubEntries(0) { }
+
+ unsigned getLoopDepth();
+ bool branchStackContains(CFStack::StackItem);
+ bool requiresWorkAroundForInst(unsigned Opcode);
+ unsigned getSubEntrySize(CFStack::StackItem Item);
+ void updateMaxStackSize();
+ void pushBranch(unsigned Opcode, bool isWQM = false);
+ void pushLoop();
+ void popBranch();
+ void popLoop();
+};
+
+unsigned CFStack::getLoopDepth() {
+ return LoopStack.size();
+}
+
+bool CFStack::branchStackContains(CFStack::StackItem Item) {
+ for (std::vector<CFStack::StackItem>::const_iterator I = BranchStack.begin(),
+ E = BranchStack.end(); I != E; ++I) {
+ if (*I == Item)
+ return true;
+ }
+ return false;
+}
+
+unsigned CFStack::getSubEntrySize(CFStack::StackItem Item) {
+ switch(Item) {
+ default:
+ return 0;
+ case CFStack::FIRST_NON_WQM_PUSH:
+ assert(!ST.hasCaymanISA());
+ if (ST.getGeneration() <= AMDGPUSubtarget::R700) {
+ // +1 For the push operation.
+ // +2 Extra space required.
+ return 3;
+ } else {
+ // Some documentation says that this is not necessary on Evergreen,
+ // but experimentation has show that we need to allocate 1 extra
+ // sub-entry for the first non-WQM push.
+ // +1 For the push operation.
+ // +1 Extra space required.
+ return 2;
+ }
+ case CFStack::FIRST_NON_WQM_PUSH_W_FULL_ENTRY:
+ assert(ST.getGeneration() >= AMDGPUSubtarget::EVERGREEN);
+ // +1 For the push operation.
+ // +1 Extra space required.
+ return 2;
+ case CFStack::SUB_ENTRY:
+ return 1;
+ }
+}
+
+void CFStack::updateMaxStackSize() {
+ unsigned CurrentStackSize = CurrentEntries +
+ (RoundUpToAlignment(CurrentSubEntries, 4) / 4);
+ MaxStackSize = std::max(CurrentStackSize, MaxStackSize);
+}
+
+void CFStack::pushBranch(unsigned Opcode, bool isWQM) {
+ CFStack::StackItem Item = CFStack::ENTRY;
+ switch(Opcode) {
+ case AMDGPU::CF_PUSH_EG:
+ case AMDGPU::CF_ALU_PUSH_BEFORE:
+ if (!isWQM) {
+ if (!ST.hasCaymanISA() && !branchStackContains(CFStack::FIRST_NON_WQM_PUSH))
+ Item = CFStack::FIRST_NON_WQM_PUSH; // May not be required on Evergreen/NI
+ // See comment in
+ // CFStack::getSubEntrySize()
+ else if (CurrentEntries > 0 &&
+ ST.getGeneration() > AMDGPUSubtarget::EVERGREEN &&
+ !ST.hasCaymanISA() &&
+ !branchStackContains(CFStack::FIRST_NON_WQM_PUSH_W_FULL_ENTRY))
+ Item = CFStack::FIRST_NON_WQM_PUSH_W_FULL_ENTRY;
+ else
+ Item = CFStack::SUB_ENTRY;
+ } else
+ Item = CFStack::ENTRY;
+ break;
+ }
+ BranchStack.push_back(Item);
+ if (Item == CFStack::ENTRY)
+ CurrentEntries++;
+ else
+ CurrentSubEntries += getSubEntrySize(Item);
+ updateMaxStackSize();
+}
+
+void CFStack::pushLoop() {
+ LoopStack.push_back(CFStack::ENTRY);
+ CurrentEntries++;
+ updateMaxStackSize();
+}
+
+void CFStack::popBranch() {
+ CFStack::StackItem Top = BranchStack.back();
+ if (Top == CFStack::ENTRY)
+ CurrentEntries--;
+ else
+ CurrentSubEntries-= getSubEntrySize(Top);
+ BranchStack.pop_back();
+}
+
+void CFStack::popLoop() {
+ CurrentEntries--;
+ LoopStack.pop_back();
+}
+
class R600ControlFlowFinalizer : public MachineFunctionPass {
private:
@@ -300,24 +428,6 @@ private:
}
}
- unsigned getHWStackSize(unsigned StackSubEntry, bool hasPush) const {
- switch (ST.getGeneration()) {
- case AMDGPUSubtarget::R600:
- case AMDGPUSubtarget::R700:
- if (hasPush)
- StackSubEntry += 2;
- break;
- case AMDGPUSubtarget::EVERGREEN:
- if (hasPush)
- StackSubEntry ++;
- case AMDGPUSubtarget::NORTHERN_ISLANDS:
- StackSubEntry += 2;
- break;
- default: llvm_unreachable("Not a VLIW4/VLIW5 GPU");
- }
- return (StackSubEntry + 3)/4; // Need ceil value of StackSubEntry/4
- }
-
public:
R600ControlFlowFinalizer(TargetMachine &tm) : MachineFunctionPass(ID),
TII (0), TRI(0),
@@ -329,23 +439,19 @@ public:
virtual bool runOnMachineFunction(MachineFunction &MF) {
TII=static_cast<const R600InstrInfo *>(MF.getTarget().getInstrInfo());
TRI=static_cast<const R600RegisterInfo *>(MF.getTarget().getRegisterInfo());
+ R600MachineFunctionInfo *MFI = MF.getInfo<R600MachineFunctionInfo>();
- unsigned MaxStack = 0;
- unsigned CurrentStack = 0;
- unsigned CurrentLoopDepth = 0;
- bool HasPush = false;
+ CFStack CFStack(ST, MFI->ShaderType);
for (MachineFunction::iterator MB = MF.begin(), ME = MF.end(); MB != ME;
++MB) {
MachineBasicBlock &MBB = *MB;
unsigned CfCount = 0;
std::vector<std::pair<unsigned, std::set<MachineInstr *> > > LoopStack;
std::vector<MachineInstr * > IfThenElseStack;
- R600MachineFunctionInfo *MFI = MF.getInfo<R600MachineFunctionInfo>();
if (MFI->ShaderType == 1) {
BuildMI(MBB, MBB.begin(), MBB.findDebugLoc(MBB.begin()),
getHWInstrDesc(CF_CALL_FS));
CfCount++;
- MaxStack = 1;
}
std::vector<ClauseFile> FetchClauses, AluClauses;
std::vector<MachineInstr *> LastAlu(1);
@@ -368,16 +474,16 @@ public:
I++;
switch (MI->getOpcode()) {
case AMDGPU::CF_ALU_PUSH_BEFORE:
- CurrentStack++;
- MaxStack = std::max(MaxStack, CurrentStack);
- HasPush = true;
- if (ST.hasCaymanISA() && CurrentLoopDepth > 1) {
+ if (ST.hasCaymanISA() && CFStack.getLoopDepth() > 1) {
BuildMI(MBB, MI, MBB.findDebugLoc(MI), TII->get(AMDGPU::CF_PUSH_EG))
.addImm(CfCount + 1)
.addImm(1);
MI->setDesc(TII->get(AMDGPU::CF_ALU));
CfCount++;
- }
+ CFStack.pushBranch(AMDGPU::CF_PUSH_EG);
+ } else
+ CFStack.pushBranch(AMDGPU::CF_ALU_PUSH_BEFORE);
+
case AMDGPU::CF_ALU:
I = MI;
AluClauses.push_back(MakeALUClause(MBB, I));
@@ -385,9 +491,7 @@ public:
CfCount++;
break;
case AMDGPU::WHILELOOP: {
- CurrentStack+=4;
- CurrentLoopDepth++;
- MaxStack = std::max(MaxStack, CurrentStack);
+ CFStack.pushLoop();
MachineInstr *MIb = BuildMI(MBB, MI, MBB.findDebugLoc(MI),
getHWInstrDesc(CF_WHILE_LOOP))
.addImm(1);
@@ -400,8 +504,7 @@ public:
break;
}
case AMDGPU::ENDLOOP: {
- CurrentStack-=4;
- CurrentLoopDepth--;
+ CFStack.popLoop();
std::pair<unsigned, std::set<MachineInstr *> > Pair =
LoopStack.back();
LoopStack.pop_back();
@@ -439,7 +542,7 @@ public:
break;
}
case AMDGPU::ENDIF: {
- CurrentStack--;
+ CFStack.popBranch();
if (LastAlu.back()) {
ToPopAfter.push_back(LastAlu.back());
} else {
@@ -514,7 +617,7 @@ public:
.addImm(Alu->getOperand(8).getImm());
Alu->eraseFromParent();
}
- MFI->StackSize = getHWStackSize(MaxStack, HasPush);
+ MFI->StackSize = CFStack.MaxStackSize;
}
return false;
Modified: llvm/trunk/test/CodeGen/R600/elf.r600.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/R600/elf.r600.ll?rev=199840&r1=199839&r2=199840&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/R600/elf.r600.ll (original)
+++ llvm/trunk/test/CodeGen/R600/elf.r600.ll Wed Jan 22 15:55:43 2014
@@ -6,7 +6,7 @@
; CONFIG-CHECK: .section .AMDGPU.config
; CONFIG-CHECK-NEXT: .long 166100
-; CONFIG-CHECK-NEXT: .long 258
+; CONFIG-CHECK-NEXT: .long 2
; CONFIG-CHECK-NEXT: .long 165900
; CONFIG-CHECK-NEXT: .long 0
define void @test(float addrspace(1)* %out, i32 %p) {
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