#define DEBUG_TYPE "sched"
#include "PPCHazardRecognizers.h"
#include "PPC.h"
+#include "PPCInstrInfo.h"
#include "llvm/Support/Debug.h"
#include <iostream>
using namespace llvm;
// PowerPC 970 Hazard Recognizer
//
// This models the dispatch group formation of the PPC970 processor. Dispatch
-// groups are bundles of up to five instructions that can contain up to two ALU
-// (aka FXU) ops, two FPU ops, two Load/Store ops, one CR op, one VALU op, one
-// VPERM op, and one BRANCH op. If the code contains more instructions in a
-// sequence than the dispatch group can contain (e.g. three loads in a row) the
-// processor terminates the dispatch group early, wasting execution resources.
+// groups are bundles of up to five instructions that can contain various mixes
+// of instructions. The PPC970 can dispatch a peak of 4 non-branch and one
+// branch instruction per-cycle.
//
-// In addition to these restrictions, there are a number of other restrictions:
-// some instructions, e.g. branches, are required to be the last instruction in
-// a group. Additionally, only branches can issue in the 5th (last) slot.
+// There are a number of restrictions to dispatch group formation: some
+// instructions can only be issued in the first slot of a dispatch group, & some
+// instructions fill an entire dispatch group. Additionally, only branches can
+// issue in the 5th (last) slot.
//
// Finally, there are a number of "structural" hazards on the PPC970. These
// conditions cause large performance penalties due to misprediction, recovery,
// conditions, we insert no-op instructions when appropriate.
//
// FIXME: This is missing some significant cases:
-// 0. Handling of instructions that must be the first/last in a group.
// 1. Modeling of microcoded instructions.
-// 2. Handling of cracked instructions.
-// 3. Handling of serialized operations.
-// 4. Handling of the esoteric cases in "Resource-based Instruction Grouping",
-// e.g. integer divides that only execute in the second slot.
+// 2. Handling of serialized operations.
+// 3. Handling of the esoteric cases in "Resource-based Instruction Grouping".
//
+PPCHazardRecognizer970::PPCHazardRecognizer970(const TargetInstrInfo &tii)
+ : TII(tii) {
+ EndDispatchGroup();
+}
+
void PPCHazardRecognizer970::EndDispatchGroup() {
DEBUG(std::cerr << "=== Start of dispatch group\n");
- // Pipeline units.
- NumFXU = NumLSU = NumFPU = 0;
- HasCR = HasVALU = HasVPERM = false;
NumIssued = 0;
// Structural hazard info.
HasCTRSet = false;
- StorePtr1 = StorePtr2 = SDOperand();
- StoreSize = 0;
+ NumStores = 0;
}
-PPCHazardRecognizer970::PPC970InstrType
-PPCHazardRecognizer970::GetInstrType(unsigned Opcode) {
- if (Opcode < ISD::BUILTIN_OP_END)
- return PseudoInst;
+PPCII::PPC970_Unit
+PPCHazardRecognizer970::GetInstrType(unsigned Opcode,
+ bool &isFirst, bool &isSingle,
+ bool &isCracked,
+ bool &isLoad, bool &isStore) {
+ if (Opcode < ISD::BUILTIN_OP_END) {
+ isFirst = isSingle = isCracked = isLoad = isStore = false;
+ return PPCII::PPC970_Pseudo;
+ }
Opcode -= ISD::BUILTIN_OP_END;
- switch (Opcode) {
- case PPC::FMRSD: return PseudoInst; // Usually coallesced away.
- case PPC::BCTRL:
- case PPC::BL:
- case PPC::BLA:
- return BR;
- case PPC::LFS:
- case PPC::LWZ:
- return LSU_LD;
- case PPC::STFD:
- return LSU_ST;
- case PPC::FADDS:
- case PPC::FCTIWZ:
- return FPU;
- }
+ const TargetInstrDescriptor &TID = TII.get(Opcode);
- return FXU;
-}
-
-
-/// StartBasicBlock - Initiate a new dispatch group.
-void PPCHazardRecognizer970::StartBasicBlock() {
- EndDispatchGroup();
+ isLoad = TID.Flags & M_LOAD_FLAG;
+ isStore = TID.Flags & M_STORE_FLAG;
+
+ unsigned TSFlags = TID.TSFlags;
+
+ isFirst = TSFlags & PPCII::PPC970_First;
+ isSingle = TSFlags & PPCII::PPC970_Single;
+ isCracked = TSFlags & PPCII::PPC970_Cracked;
+ return (PPCII::PPC970_Unit)(TSFlags & PPCII::PPC970_Mask);
}
/// isLoadOfStoredAddress - If we have a load from the previously stored pointer
/// as indicated by StorePtr1/StorePtr2/StoreSize, return true.
bool PPCHazardRecognizer970::
isLoadOfStoredAddress(unsigned LoadSize, SDOperand Ptr1, SDOperand Ptr2) const {
- // Handle exact and commuted addresses.
- if (Ptr1 == StorePtr1 && Ptr2 == StorePtr2)
- return true;
- if (Ptr2 == StorePtr1 && Ptr1 == StorePtr2)
- return true;
-
- // Okay, we don't have an exact match, if this is an indexed offset, see if we
- // have overlap (which happens during fp->int conversion for example).
- if (StorePtr2 == Ptr2) {
- if (ConstantSDNode *StoreOffset = dyn_cast<ConstantSDNode>(StorePtr1))
- if (ConstantSDNode *LoadOffset = dyn_cast<ConstantSDNode>(Ptr1)) {
- // Okay the base pointers match, so we have [c1+r] vs [c2+r]. Check to
- // see if the load and store actually overlap.
- int StoreOffs = StoreOffset->getValue();
- int LoadOffs = LoadOffset->getValue();
- if (StoreOffs < LoadOffs) {
- if (int(StoreOffs+StoreSize) > LoadOffs) return true;
- } else {
- if (int(LoadOffs+LoadSize) > StoreOffs) return true;
+ for (unsigned i = 0, e = NumStores; i != e; ++i) {
+ // Handle exact and commuted addresses.
+ if (Ptr1 == StorePtr1[i] && Ptr2 == StorePtr2[i])
+ return true;
+ if (Ptr2 == StorePtr1[i] && Ptr1 == StorePtr2[i])
+ return true;
+
+ // Okay, we don't have an exact match, if this is an indexed offset, see if
+ // we have overlap (which happens during fp->int conversion for example).
+ if (StorePtr2[i] == Ptr2) {
+ if (ConstantSDNode *StoreOffset = dyn_cast<ConstantSDNode>(StorePtr1[i]))
+ if (ConstantSDNode *LoadOffset = dyn_cast<ConstantSDNode>(Ptr1)) {
+ // Okay the base pointers match, so we have [c1+r] vs [c2+r]. Check
+ // to see if the load and store actually overlap.
+ int StoreOffs = StoreOffset->getValue();
+ int LoadOffs = LoadOffset->getValue();
+ if (StoreOffs < LoadOffs) {
+ if (int(StoreOffs+StoreSize[i]) > LoadOffs) return true;
+ } else {
+ if (int(LoadOffs+LoadSize) > StoreOffs) return true;
+ }
}
- }
+ }
}
return false;
}
/// pipeline flush.
HazardRecognizer::HazardType PPCHazardRecognizer970::
getHazardType(SDNode *Node) {
- PPC970InstrType InstrType = GetInstrType(Node->getOpcode());
- if (InstrType == PseudoInst) return NoHazard;
+ bool isFirst, isSingle, isCracked, isLoad, isStore;
+ PPCII::PPC970_Unit InstrType =
+ GetInstrType(Node->getOpcode(), isFirst, isSingle, isCracked,
+ isLoad, isStore);
+ if (InstrType == PPCII::PPC970_Pseudo) return NoHazard;
unsigned Opcode = Node->getOpcode()-ISD::BUILTIN_OP_END;
+ // We can only issue a PPC970_First/PPC970_Single instruction (such as
+ // crand/mtspr/etc) if this is the first cycle of the dispatch group.
+ if (NumIssued != 0 && (isFirst || isSingle))
+ return Hazard;
+
+ // If this instruction is cracked into two ops by the decoder, we know that
+ // it is not a branch and that it cannot issue if 3 other instructions are
+ // already in the dispatch group.
+ if (isCracked && NumIssued > 2)
+ return Hazard;
+
switch (InstrType) {
default: assert(0 && "Unknown instruction type!");
- case FXU: if (NumFXU == 2) return Hazard;
- case LSU_ST:
- case LSU_LD: if (NumLSU == 2) return Hazard;
- case FPU: if (NumFPU == 2) return Hazard;
- case CR: if (HasCR) return Hazard;
- case VALU: if (HasVALU) return Hazard;
- case VPERM: if (HasVPERM) return Hazard;
- case BR: break;
+ case PPCII::PPC970_FXU:
+ case PPCII::PPC970_LSU:
+ case PPCII::PPC970_FPU:
+ case PPCII::PPC970_VALU:
+ case PPCII::PPC970_VPERM:
+ // We can only issue a branch as the last instruction in a group.
+ if (NumIssued == 4) return Hazard;
+ break;
+ case PPCII::PPC970_CRU:
+ // We can only issue a CR instruction in the first two slots.
+ if (NumIssued >= 2) return Hazard;
+ break;
+ case PPCII::PPC970_BRU:
+ break;
}
-
- // We can only issue a branch as the last instruction in a group.
- if (NumIssued == 4 && InstrType != BR)
- return Hazard;
// Do not allow MTCTR and BCTRL to be in the same dispatch group.
if (HasCTRSet && Opcode == PPC::BCTRL)
// If this is a load following a store, make sure it's not to the same or
// overlapping address.
- if (InstrType == LSU_LD && StoreSize) {
+ if (isLoad && NumStores) {
unsigned LoadSize;
switch (Opcode) {
default: assert(0 && "Unknown load!");
+ case PPC::LBZ:
+ case PPC::LBZX:
+ case PPC::LVEBX:
+ LoadSize = 1;
+ break;
+ case PPC::LHA:
+ case PPC::LHAX:
+ case PPC::LHZ:
+ case PPC::LHZX:
+ case PPC::LVEHX:
+ LoadSize = 2;
+ break;
case PPC::LFS:
- case PPC::LWZ: LoadSize = 4; break;
+ case PPC::LFSX:
+ case PPC::LWZ:
+ case PPC::LWZX:
+ case PPC::LWZU:
+ case PPC::LWA:
+ case PPC::LWAX:
+ case PPC::LVEWX:
+ LoadSize = 4;
+ break;
+ case PPC::LFD:
+ case PPC::LFDX:
+ case PPC::LD:
+ case PPC::LDX:
+ LoadSize = 8;
+ break;
+ case PPC::LVX:
+ LoadSize = 16;
+ break;
}
if (isLoadOfStoredAddress(LoadSize,
}
void PPCHazardRecognizer970::EmitInstruction(SDNode *Node) {
- PPC970InstrType InstrType = GetInstrType(Node->getOpcode());
- if (InstrType == PseudoInst) return;
+ bool isFirst, isSingle, isCracked, isLoad, isStore;
+ PPCII::PPC970_Unit InstrType =
+ GetInstrType(Node->getOpcode(), isFirst, isSingle, isCracked,
+ isLoad, isStore);
+ if (InstrType == PPCII::PPC970_Pseudo) return;
unsigned Opcode = Node->getOpcode()-ISD::BUILTIN_OP_END;
// Update structural hazard information.
if (Opcode == PPC::MTCTR) HasCTRSet = true;
// Track the address stored to.
- if (InstrType == LSU_ST) {
- StorePtr1 = Node->getOperand(1);
- StorePtr2 = Node->getOperand(2);
+ if (isStore) {
+ unsigned ThisStoreSize;
switch (Opcode) {
default: assert(0 && "Unknown store instruction!");
- case PPC::STFD: StoreSize = 8; break;
+ case PPC::STBX:
+ case PPC::STB:
+ case PPC::STVEBX:
+ ThisStoreSize = 1;
+ break;
+ case PPC::STHX:
+ case PPC::STH:
+ case PPC::STVEHX:
+ ThisStoreSize = 2;
+ break;
+ case PPC::STFS:
+ case PPC::STFSX:
+ case PPC::STWU:
+ case PPC::STWX:
+ case PPC::STWUX:
+ case PPC::STW:
+ case PPC::STVEWX:
+ case PPC::STFIWX:
+ ThisStoreSize = 4;
+ break;
+ case PPC::STD_32:
+ case PPC::STDX_32:
+ case PPC::STD:
+ case PPC::STFD:
+ case PPC::STFDX:
+ case PPC::STDX:
+ case PPC::STDUX:
+ ThisStoreSize = 8;
+ break;
+ case PPC::STVX:
+ ThisStoreSize = 16;
+ break;
}
+
+ StoreSize[NumStores] = ThisStoreSize;
+ StorePtr1[NumStores] = Node->getOperand(1);
+ StorePtr2[NumStores] = Node->getOperand(2);
+ ++NumStores;
}
- switch (InstrType) {
- default: assert(0 && "Unknown instruction type!");
- case FXU: ++NumFXU; break;
- case LSU_LD:
- case LSU_ST: ++NumLSU; break;
- case FPU: ++NumFPU; break;
- case CR: HasCR = true; break;
- case VALU: HasVALU = true; break;
- case VPERM: HasVPERM = true; break;
- case BR: NumIssued = 4; return; // ends a d-group.
- }
+ if (InstrType == PPCII::PPC970_BRU || isSingle)
+ NumIssued = 4; // Terminate a d-group.
++NumIssued;
+ // If this instruction is cracked into two ops by the decoder, remember that
+ // we issued two pieces.
+ if (isCracked)
+ ++NumIssued;
+
if (NumIssued == 5)
EndDispatchGroup();
}
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