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Teach if-converter to be more careful with predicating instructions that would

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take multiple cycles to decode.
For the current if-converter clients (actually only ARM), the instructions that
are predicated on false are not nops. They would still take machine cycles to
decode. Micro-coded instructions such as LDM / STM can potentially take multiple
cycles to decode. If-converter should take treat them as non-micro-coded
simple instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113570 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2010-09-10 01:29:16 +00:00
parent 920a2089d9
commit 3ef1c8759a
28 changed files with 160 additions and 80 deletions
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22
lib/CodeGen/PostRAHazardRecognizer.cpp
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@@ -23,19 +23,19 @@
using namespace llvm;
PostRAHazardRecognizer::
PostRAHazardRecognizer(const InstrItineraryData &LItinData) :
PostRAHazardRecognizer(const InstrItineraryData *LItinData) :
ScheduleHazardRecognizer(), ItinData(LItinData) {
// Determine the maximum depth of any itinerary. This determines the
// depth of the scoreboard. We always make the scoreboard at least 1
// cycle deep to avoid dealing with the boundary condition.
unsigned ScoreboardDepth = 1;
if (!ItinData.isEmpty()) {
if (ItinData && !ItinData->isEmpty()) {
for (unsigned idx = 0; ; ++idx) {
if (ItinData.isEndMarker(idx))
if (ItinData->isEndMarker(idx))
break;
const InstrStage *IS = ItinData.beginStage(idx);
const InstrStage *E = ItinData.endStage(idx);
const InstrStage *IS = ItinData->beginStage(idx);
const InstrStage *E = ItinData->endStage(idx);
unsigned ItinDepth = 0;
for (; IS != E; ++IS)
ItinDepth += IS->getCycles();
@@ -74,7 +74,7 @@ void PostRAHazardRecognizer::ScoreBoard::dump() const {
ScheduleHazardRecognizer::HazardType
PostRAHazardRecognizer::getHazardType(SUnit *SU) {
if (ItinData.isEmpty())
if (!ItinData || ItinData->isEmpty())
return NoHazard;
unsigned cycle = 0;
@@ -82,8 +82,8 @@ PostRAHazardRecognizer::getHazardType(SUnit *SU) {
// Use the itinerary for the underlying instruction to check for
// free FU's in the scoreboard at the appropriate future cycles.
unsigned idx = SU->getInstr()->getDesc().getSchedClass();
for (const InstrStage *IS = ItinData.beginStage(idx),
*E = ItinData.endStage(idx); IS != E; ++IS) {
for (const InstrStage *IS = ItinData->beginStage(idx),
*E = ItinData->endStage(idx); IS != E; ++IS) {
// We must find one of the stage's units free for every cycle the
// stage is occupied. FIXME it would be more accurate to find the
// same unit free in all the cycles.
@@ -121,7 +121,7 @@ PostRAHazardRecognizer::getHazardType(SUnit *SU) {
}
void PostRAHazardRecognizer::EmitInstruction(SUnit *SU) {
if (ItinData.isEmpty())
if (!ItinData || ItinData->isEmpty())
return;
unsigned cycle = 0;
@@ -129,8 +129,8 @@ void PostRAHazardRecognizer::EmitInstruction(SUnit *SU) {
// Use the itinerary for the underlying instruction to reserve FU's
// in the scoreboard at the appropriate future cycles.
unsigned idx = SU->getInstr()->getDesc().getSchedClass();
for (const InstrStage *IS = ItinData.beginStage(idx),
*E = ItinData.endStage(idx); IS != E; ++IS) {
for (const InstrStage *IS = ItinData->beginStage(idx),
*E = ItinData->endStage(idx); IS != E; ++IS) {
// We must reserve one of the stage's units for every cycle the
// stage is occupied. FIXME it would be more accurate to reserve
// the same unit free in all the cycles.