[Mesa-dev] [PATCH] Revert "radeon/llvm: Inital flow control support for SI"
Michel Dänzer
michel at daenzer.net
Fri Sep 28 09:24:13 PDT 2012
From: Michel Dänzer <michel.daenzer at amd.com>
This reverts commit bfd55711c1eb32ffbfceb9d566abae98f0015f23.
It makes piglit unreliable due to VM protection faults and GPU lockups.
Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
Not sure why I wasn't seeing the piglit unreliablity when I tested the patch
before it was applied... I'm not sure how the patch could cause those issues
directly, so it may be pre-existing bugs merely exposed by it. But either way,
we need to make sure piglit works reliably with this before we can apply it
again.
src/gallium/drivers/radeon/AMDGPU.h | 1 -
src/gallium/drivers/radeon/AMDGPUTargetMachine.cpp | 1 -
.../drivers/radeon/AMDILCFGStructurizer.cpp | 2 -
src/gallium/drivers/radeon/AMDILInstrInfo.td | 2 +-
src/gallium/drivers/radeon/Makefile.sources | 1 -
src/gallium/drivers/radeon/SIISelLowering.cpp | 2 +-
src/gallium/drivers/radeon/SILowerFlowControl.cpp | 161 --------------------
7 files changed, 2 insertions(+), 168 deletions(-)
delete mode 100644 src/gallium/drivers/radeon/SILowerFlowControl.cpp
diff --git a/src/gallium/drivers/radeon/AMDGPU.h b/src/gallium/drivers/radeon/AMDGPU.h
index f484caa..fe36545 100644
--- a/src/gallium/drivers/radeon/AMDGPU.h
+++ b/src/gallium/drivers/radeon/AMDGPU.h
@@ -25,7 +25,6 @@ FunctionPass *createR600ExpandSpecialInstrsPass(TargetMachine &tm);
// SI Passes
FunctionPass *createSIAssignInterpRegsPass(TargetMachine &tm);
-FunctionPass *createSILowerFlowControlPass(TargetMachine &tm);
FunctionPass *createSICodeEmitterPass(formatted_raw_ostream &OS);
FunctionPass *createSILowerLiteralConstantsPass(TargetMachine &tm);
diff --git a/src/gallium/drivers/radeon/AMDGPUTargetMachine.cpp b/src/gallium/drivers/radeon/AMDGPUTargetMachine.cpp
index 0b70191..c1b6840 100644
--- a/src/gallium/drivers/radeon/AMDGPUTargetMachine.cpp
+++ b/src/gallium/drivers/radeon/AMDGPUTargetMachine.cpp
@@ -134,7 +134,6 @@ bool AMDGPUPassConfig::addPreEmitPass() {
addPass(FinalizeMachineBundlesID);
} else {
PM->add(createSILowerLiteralConstantsPass(*TM));
- PM->add(createSILowerFlowControlPass(*TM));
}
return false;
diff --git a/src/gallium/drivers/radeon/AMDILCFGStructurizer.cpp b/src/gallium/drivers/radeon/AMDILCFGStructurizer.cpp
index 20e27ef..b167d62 100644
--- a/src/gallium/drivers/radeon/AMDILCFGStructurizer.cpp
+++ b/src/gallium/drivers/radeon/AMDILCFGStructurizer.cpp
@@ -2892,8 +2892,6 @@ struct CFGStructTraits<AMDGPUCFGStructurizer>
switch (instr->getOpcode()) {
case AMDGPU::JUMP:
return instr->getOperand(instr->findFirstPredOperandIdx()).getReg() == 0;
- case AMDGPU::BRANCH:
- return true;
default:
return false;
}
diff --git a/src/gallium/drivers/radeon/AMDILInstrInfo.td b/src/gallium/drivers/radeon/AMDILInstrInfo.td
index 050a5bd..f8771af 100644
--- a/src/gallium/drivers/radeon/AMDILInstrInfo.td
+++ b/src/gallium/drivers/radeon/AMDILInstrInfo.td
@@ -211,7 +211,7 @@ include "AMDILIntrinsics.td"
// Custom Inserter for Branches and returns, this eventually will be a
// seperate pass
//===---------------------------------------------------------------------===//
-let isTerminator = 1, usesCustomInserter = 1, isBranch = 1, isBarrier = 1 in {
+let isTerminator = 1, usesCustomInserter = 1 in {
def BRANCH : ILFormat<(outs), (ins brtarget:$target),
"; Pseudo unconditional branch instruction",
[(br bb:$target)]>;
diff --git a/src/gallium/drivers/radeon/Makefile.sources b/src/gallium/drivers/radeon/Makefile.sources
index c5d1207..4b0699b 100644
--- a/src/gallium/drivers/radeon/Makefile.sources
+++ b/src/gallium/drivers/radeon/Makefile.sources
@@ -71,7 +71,6 @@ CPP_SOURCES := \
SIInstrInfo.cpp \
SIISelLowering.cpp \
SILowerLiteralConstants.cpp \
- SILowerFlowControl.cpp \
SIMachineFunctionInfo.cpp \
SIRegisterInfo.cpp \
InstPrinter/AMDGPUInstPrinter.cpp \
diff --git a/src/gallium/drivers/radeon/SIISelLowering.cpp b/src/gallium/drivers/radeon/SIISelLowering.cpp
index 7c2739c..3f23949 100644
--- a/src/gallium/drivers/radeon/SIISelLowering.cpp
+++ b/src/gallium/drivers/radeon/SIISelLowering.cpp
@@ -78,7 +78,7 @@ MachineBasicBlock * SITargetLowering::EmitInstrWithCustomInserter(
switch (MI->getOpcode()) {
default:
return AMDGPUTargetLowering::EmitInstrWithCustomInserter(MI, BB);
- case AMDGPU::BRANCH: return BB;
+
case AMDGPU::CLAMP_SI:
BuildMI(*BB, I, BB->findDebugLoc(I), TII->get(AMDGPU::V_MOV_B32_e64))
.addOperand(MI->getOperand(0))
diff --git a/src/gallium/drivers/radeon/SILowerFlowControl.cpp b/src/gallium/drivers/radeon/SILowerFlowControl.cpp
deleted file mode 100644
index bf5192e..0000000
--- a/src/gallium/drivers/radeon/SILowerFlowControl.cpp
+++ /dev/null
@@ -1,161 +0,0 @@
-//===-- SILowerFlowControl.cpp - Use predicates for flow control ----------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass lowers the pseudo flow control instructions (SI_IF_NZ, ELSE, ENDIF)
-// to predicated instructions.
-//
-// All flow control (except loops) is handled using predicated instructions and
-// a predicate stack. Each Scalar ALU controls the operations of 64 Vector
-// ALUs. The Scalar ALU can update the predicate for any of the Vector ALUs
-// by writting to the 64-bit EXEC register (each bit corresponds to a
-// single vector ALU). Typically, for predicates, a vector ALU will write
-// to its bit of the VCC register (like EXEC VCC is 64-bits, one for each
-// Vector ALU) and then the ScalarALU will AND the VCC register with the
-// EXEC to update the predicates.
-//
-// For example:
-// %VCC = V_CMP_GT_F32 %VGPR1, %VGPR2
-// SI_IF_NZ %VCC
-// %VGPR0 = V_ADD_F32 %VGPR0, %VGPR0
-// ELSE
-// %VGPR0 = V_SUB_F32 %VGPR0, %VGPR0
-// ENDIF
-//
-// becomes:
-//
-// %SGPR0 = S_MOV_B64 %EXEC // Save the current exec mask
-// %EXEC = S_AND_B64 %VCC, %EXEC // Update the exec mask
-// S_CBRANCH_EXECZ label0 // This instruction is an
-// // optimization which allows us to
-// // branch if all the bits of
-// // EXEC are zero.
-// %VGPR0 = V_ADD_F32 %VGPR0, %VGPR0 // Do the IF block of the branch
-//
-// label0:
-// %EXEC = S_NOT_B64 %EXEC // Invert the exec mask for the
-// // Then block.
-// %EXEC = S_AND_B64 %SGPR0, %EXEC
-// S_BRANCH_EXECZ label1 // Use our branch optimization
-// // instruction again.
-// %VGPR0 = V_SUB_F32 %VGPR0, %VGPR // Do the THEN block
-// label1:
-// S_MOV_B64 // Restore the old EXEC value
-//===----------------------------------------------------------------------===//
-
-#include "AMDGPU.h"
-#include "SIInstrInfo.h"
-#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
-
-using namespace llvm;
-
-namespace {
-
-class SILowerFlowControlPass : public MachineFunctionPass {
-
-private:
- static char ID;
- const TargetInstrInfo *TII;
- std::vector<unsigned> PredicateStack;
- std::vector<unsigned> UnusedRegisters;
-
- void pushExecMask(MachineBasicBlock &MBB, MachineBasicBlock::iterator I);
- void popExecMask(MachineBasicBlock &MBB, MachineBasicBlock::iterator I);
-
-public:
- SILowerFlowControlPass(TargetMachine &tm) :
- MachineFunctionPass(ID), TII(tm.getInstrInfo()) { }
-
- virtual bool runOnMachineFunction(MachineFunction &MF);
-
- const char *getPassName() const {
- return "SI Lower flow control instructions";
- }
-
-};
-
-} // End anonymous namespace
-
-char SILowerFlowControlPass::ID = 0;
-
-FunctionPass *llvm::createSILowerFlowControlPass(TargetMachine &tm) {
- return new SILowerFlowControlPass(tm);
-}
-
-bool SILowerFlowControlPass::runOnMachineFunction(MachineFunction &MF) {
-
- // Find all the unused registers that can be used for the predicate stack.
- for (TargetRegisterClass::iterator S = AMDGPU::SReg_64RegClass.begin(),
- I = AMDGPU::SReg_64RegClass.end();
- I != S; --I) {
- unsigned Reg = *I;
- if (!MF.getRegInfo().isPhysRegOrOverlapUsed(Reg)) {
- UnusedRegisters.push_back(Reg);
- }
- }
-
- for (MachineFunction::iterator BB = MF.begin(), BB_E = MF.end();
- BB != BB_E; ++BB) {
- MachineBasicBlock &MBB = *BB;
- for (MachineBasicBlock::iterator I = MBB.begin(), Next = llvm::next(I);
- I != MBB.end(); I = Next, Next = llvm::next(I)) {
- MachineInstr &MI = *I;
- switch (MI.getOpcode()) {
- default: break;
- case AMDGPU::SI_IF_NZ:
- pushExecMask(MBB, I);
- BuildMI(MBB, I, MBB.findDebugLoc(I), TII->get(AMDGPU::S_AND_B64),
- AMDGPU::EXEC)
- .addOperand(MI.getOperand(0)) // VCC
- .addReg(AMDGPU::EXEC);
- MI.eraseFromParent();
- break;
- case AMDGPU::ELSE:
- BuildMI(MBB, I, MBB.findDebugLoc(I), TII->get(AMDGPU::S_NOT_B64),
- AMDGPU::EXEC)
- .addReg(AMDGPU::EXEC);
- BuildMI(MBB, I, MBB.findDebugLoc(I), TII->get(AMDGPU::S_AND_B64),
- AMDGPU::EXEC)
- .addReg(PredicateStack.back())
- .addReg(AMDGPU::EXEC);
- MI.eraseFromParent();
- break;
- case AMDGPU::ENDIF:
- popExecMask(MBB, I);
- MI.eraseFromParent();
- break;
- }
- }
- }
- return false;
-}
-
-void SILowerFlowControlPass::pushExecMask(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator I) {
-
- assert(!UnusedRegisters.empty() && "Ran out of registers for predicate stack");
- unsigned StackReg = UnusedRegisters.back();
- UnusedRegisters.pop_back();
- PredicateStack.push_back(StackReg);
- BuildMI(MBB, I, MBB.findDebugLoc(I), TII->get(AMDGPU::S_MOV_B64),
- StackReg)
- .addReg(AMDGPU::EXEC);
-}
-
-void SILowerFlowControlPass::popExecMask(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator I) {
- unsigned StackReg = PredicateStack.back();
- PredicateStack.pop_back();
- UnusedRegisters.push_back(StackReg);
- BuildMI(MBB, I, MBB.findDebugLoc(I), TII->get(AMDGPU::S_MOV_B64),
- AMDGPU::EXEC)
- .addReg(StackReg);
-}
--
1.7.10.4
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