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R600: New control flow for SI v2

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This patch replaces the control flow handling with a new
pass which structurize the graph before transforming it to
machine instruction. This has a couple of different advantages
and currently fixes 20 piglit tests without a single regression.

It is now a general purpose transformation that could be not
only be used for SI/R6xx, but also for other hardware
implementations that use a form of structurized control flow.

v2: further cleanup, fixes and documentation

Patch by: Christian König

Signed-off-by: Christian König <deathsimple@vodafone.de>
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
Tested-by: Michel Dänzer <michel.daenzer@amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170591 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tom Stellard
2012-12-19 22:10:31 +00:00
parent 6eebe47060
commit 6b7d99d473
14 changed files with 1500 additions and 385 deletions
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116
lib/Target/R600/SIISelLowering.cpp
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@@ -44,8 +44,6 @@ SITargetLowering::SITargetLowering(TargetMachine &TM) :
setOperationAction(ISD::ADD, MVT::i64, Legal);
setOperationAction(ISD::ADD, MVT::i32, Legal);
setOperationAction(ISD::BR_CC, MVT::i32, Custom);
setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);
// We need to custom lower loads from the USER_SGPR address space, so we can
@@ -254,7 +252,7 @@ EVT SITargetLowering::getSetCCResultType(EVT VT) const {
SDValue SITargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
switch (Op.getOpcode()) {
default: return AMDGPUTargetLowering::LowerOperation(Op, DAG);
case ISD::BR_CC: return LowerBR_CC(Op, DAG);
case ISD::BRCOND: return LowerBRCOND(Op, DAG);
case ISD::LOAD: return LowerLOAD(Op, DAG);
case ISD::SELECT_CC: return LowerSELECT_CC(Op, DAG);
case ISD::AND: return Loweri1ContextSwitch(Op, DAG, ISD::AND);
@@ -298,27 +296,99 @@ SDValue SITargetLowering::Loweri1ContextSwitch(SDValue Op,
return DAG.getNode(SIISD::VCC_BITCAST, DL, MVT::i1, OpNode);
}
SDValue SITargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) const {
SDValue Chain = Op.getOperand(0);
SDValue CC = Op.getOperand(1);
SDValue LHS = Op.getOperand(2);
SDValue RHS = Op.getOperand(3);
SDValue JumpT = Op.getOperand(4);
SDValue CmpValue;
SDValue Result;
CmpValue = DAG.getNode(
ISD::SETCC,
Op.getDebugLoc(),
MVT::i1,
LHS, RHS,
CC);
/// \brief Helper function for LowerBRCOND
static SDNode *findUser(SDValue Value, unsigned Opcode) {
Result = DAG.getNode(
AMDGPUISD::BRANCH_COND,
CmpValue.getDebugLoc(),
MVT::Other, Chain,
JumpT, CmpValue);
return Result;
SDNode *Parent = Value.getNode();
for (SDNode::use_iterator I = Parent->use_begin(), E = Parent->use_end();
I != E; ++I) {
if (I.getUse().get() != Value)
continue;
if (I->getOpcode() == Opcode)
return *I;
}
return 0;
}
/// This transforms the control flow intrinsics to get the branch destination as
/// last parameter, also switches branch target with BR if the need arise
SDValue SITargetLowering::LowerBRCOND(SDValue BRCOND,
SelectionDAG &DAG) const {
DebugLoc DL = BRCOND.getDebugLoc();
SDNode *Intr = BRCOND.getOperand(1).getNode();
SDValue Target = BRCOND.getOperand(2);
SDNode *BR = 0;
if (Intr->getOpcode() == ISD::SETCC) {
// As long as we negate the condition everything is fine
SDNode *SetCC = Intr;
assert(SetCC->getConstantOperandVal(1) == 1);
CondCodeSDNode *CC = cast<CondCodeSDNode>(SetCC->getOperand(2).getNode());
assert(CC->get() == ISD::SETNE);
Intr = SetCC->getOperand(0).getNode();
} else {
// Get the target from BR if we don't negate the condition
BR = findUser(BRCOND, ISD::BR);
Target = BR->getOperand(1);
}
assert(Intr->getOpcode() == ISD::INTRINSIC_W_CHAIN);
// Build the result and
SmallVector<EVT, 4> Res;
for (unsigned i = 1, e = Intr->getNumValues(); i != e; ++i)
Res.push_back(Intr->getValueType(i));
// operands of the new intrinsic call
SmallVector<SDValue, 4> Ops;
Ops.push_back(BRCOND.getOperand(0));
for (unsigned i = 1, e = Intr->getNumOperands(); i != e; ++i)
Ops.push_back(Intr->getOperand(i));
Ops.push_back(Target);
// build the new intrinsic call
SDNode *Result = DAG.getNode(
Res.size() > 1 ? ISD::INTRINSIC_W_CHAIN : ISD::INTRINSIC_VOID, DL,
DAG.getVTList(Res.data(), Res.size()), Ops.data(), Ops.size()).getNode();
if (BR) {
// Give the branch instruction our target
SDValue Ops[] = {
BR->getOperand(0),
BRCOND.getOperand(2)
};
DAG.MorphNodeTo(BR, ISD::BR, BR->getVTList(), Ops, 2);
}
SDValue Chain = SDValue(Result, Result->getNumValues() - 1);
// Copy the intrinsic results to registers
for (unsigned i = 1, e = Intr->getNumValues() - 1; i != e; ++i) {
SDNode *CopyToReg = findUser(SDValue(Intr, i), ISD::CopyToReg);
if (!CopyToReg)
continue;
Chain = DAG.getCopyToReg(
Chain, DL,
CopyToReg->getOperand(1),
SDValue(Result, i - 1),
SDValue());
DAG.ReplaceAllUsesWith(SDValue(CopyToReg, 0), CopyToReg->getOperand(0));
}
// Remove the old intrinsic from the chain
DAG.ReplaceAllUsesOfValueWith(
SDValue(Intr, Intr->getNumValues() - 1),
Intr->getOperand(0));
return Chain;
}
SDValue SITargetLowering::LowerLOAD(SDValue Op, SelectionDAG &DAG) const {