mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-12-22 03:28:35 +00:00
While calculating upper loop bound for first loop and lower loop bound for second loop, take care of edge cases.
llvm-svn: 41387
This commit is contained in:
Devang Patel
parent
666f15ac0a
commit
027410a7aa
@ -58,7 +58,8 @@ namespace {
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class SplitInfo {
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public:
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SplitInfo() : SplitValue(NULL), SplitCondition(NULL),
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UseTrueBranchFirst(true) {}
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UseTrueBranchFirst(true), A_ExitValue(NULL),
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B_StartValue(NULL) {}
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// Induction variable's range is split at this value.
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Value *SplitValue;
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@ -69,11 +70,20 @@ namespace {
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// True if after loop index split, first loop will execute split condition's
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// true branch.
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bool UseTrueBranchFirst;
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// Exit value for first loop after loop split.
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Value *A_ExitValue;
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// Start value for second loop after loop split.
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Value *B_StartValue;
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// Clear split info.
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void clear() {
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SplitValue = NULL;
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SplitCondition = NULL;
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UseTrueBranchFirst = true;
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A_ExitValue = NULL;
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B_StartValue = NULL;
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}
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};
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@ -112,6 +122,10 @@ namespace {
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/// split loop using given split condition.
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bool safeSplitCondition(SplitInfo &SD);
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/// calculateLoopBounds - ALoop exit value and BLoop start values are calculated
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/// based on split value.
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void calculateLoopBounds(SplitInfo &SD);
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/// splitLoop - Split current loop L in two loops using split information
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/// SD. Update dominator information. Maintain LCSSA form.
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bool splitLoop(SplitInfo &SD);
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@ -295,7 +309,14 @@ void LoopIndexSplit::findLoopConditionals() {
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ICmpInst *CI = dyn_cast<ICmpInst>(BR->getCondition());
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if (!CI)
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return;
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// FIXME
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if (CI->getPredicate() == ICmpInst::ICMP_SGT
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|| CI->getPredicate() == ICmpInst::ICMP_UGT
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|| CI->getPredicate() == ICmpInst::ICMP_SGE
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|| CI->getPredicate() == ICmpInst::ICMP_UGE)
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return;
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ExitCondition = CI;
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// Exit condition's one operand is loop invariant exit value and second
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@ -747,6 +768,207 @@ bool LoopIndexSplit::safeSplitCondition(SplitInfo &SD) {
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return false;
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}
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/// calculateLoopBounds - ALoop exit value and BLoop start values are calculated
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/// based on split value.
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void LoopIndexSplit::calculateLoopBounds(SplitInfo &SD) {
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ICmpInst::Predicate SP = SD.SplitCondition->getPredicate();
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const Type *Ty = SD.SplitValue->getType();
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bool Sign = ExitCondition->isSignedPredicate();
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BasicBlock *Preheader = L->getLoopPreheader();
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Instruction *PHTerminator = Preheader->getTerminator();
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// Initially use split value as upper loop bound for first loop and lower loop
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// bound for second loop.
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Value *AEV = SD.SplitValue;
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Value *BSV = SD.SplitValue;
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switch (ExitCondition->getPredicate()) {
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case ICmpInst::ICMP_SGT:
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case ICmpInst::ICMP_UGT:
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case ICmpInst::ICMP_SGE:
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case ICmpInst::ICMP_UGE:
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default:
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assert (0 && "Unexpected exit condition predicate");
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case ICmpInst::ICMP_SLT:
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case ICmpInst::ICMP_ULT:
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{
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switch (SP) {
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case ICmpInst::ICMP_SLT:
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case ICmpInst::ICMP_ULT:
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//
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// for (i = LB; i < UB; ++i) { if (i < SV) A; else B; }
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//
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// is transformed into
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// AEV = BSV = SV
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// for (i = LB; i < min(UB, AEV); ++i)
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// A;
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// for (i = max(LB, BSV); i < UB; ++i);
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// B;
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break;
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case ICmpInst::ICMP_SLE:
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case ICmpInst::ICMP_ULE:
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{
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//
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// for (i = LB; i < UB; ++i) { if (i <= SV) A; else B; }
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//
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// is transformed into
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//
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// AEV = SV + 1
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// BSV = SV + 1
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// for (i = LB; i < min(UB, AEV); ++i)
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// A;
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// for (i = max(LB, BSV); i < UB; ++i)
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// B;
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BSV = BinaryOperator::createAdd(SD.SplitValue,
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ConstantInt::get(Ty, 1, Sign),
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"lsplit.add", PHTerminator);
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AEV = BSV;
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}
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break;
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case ICmpInst::ICMP_SGE:
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case ICmpInst::ICMP_UGE:
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//
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// for (i = LB; i < UB; ++i) { if (i >= SV) A; else B; }
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//
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// is transformed into
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// AEV = BSV = SV
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// for (i = LB; i < min(UB, AEV); ++i)
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// B;
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// for (i = max(BSV, LB); i < UB; ++i)
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// A;
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break;
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case ICmpInst::ICMP_SGT:
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case ICmpInst::ICMP_UGT:
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{
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//
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// for (i = LB; i < UB; ++i) { if (i > SV) A; else B; }
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//
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// is transformed into
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//
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// BSV = AEV = SV + 1
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// for (i = LB; i < min(UB, AEV); ++i)
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// B;
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// for (i = max(LB, BSV); i < UB; ++i)
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// A;
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BSV = BinaryOperator::createAdd(SD.SplitValue,
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ConstantInt::get(Ty, 1, Sign),
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"lsplit.add", PHTerminator);
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AEV = BSV;
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}
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break;
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default:
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assert (0 && "Unexpected split condition predicate");
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break;
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} // end switch (SP)
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}
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break;
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case ICmpInst::ICMP_SLE:
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case ICmpInst::ICMP_ULE:
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{
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switch (SP) {
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case ICmpInst::ICMP_SLT:
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case ICmpInst::ICMP_ULT:
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//
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// for (i = LB; i <= UB; ++i) { if (i < SV) A; else B; }
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//
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// is transformed into
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// AEV = SV - 1;
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// BSV = SV;
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// for (i = LB; i <= min(UB, AEV); ++i)
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// A;
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// for (i = max(LB, BSV); i <= UB; ++i)
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// B;
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AEV = BinaryOperator::createSub(SD.SplitValue,
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ConstantInt::get(Ty, 1, Sign),
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"lsplit.sub", PHTerminator);
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break;
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case ICmpInst::ICMP_SLE:
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case ICmpInst::ICMP_ULE:
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//
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// for (i = LB; i <= UB; ++i) { if (i <= SV) A; else B; }
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//
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// is transformed into
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// AEV = SV;
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// BSV = SV + 1;
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// for (i = LB; i <= min(UB, AEV); ++i)
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// A;
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// for (i = max(LB, BSV); i <= UB; ++i)
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// B;
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BSV = BinaryOperator::createAdd(SD.SplitValue,
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ConstantInt::get(Ty, 1, Sign),
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"lsplit.add", PHTerminator);
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break;
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case ICmpInst::ICMP_SGT:
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case ICmpInst::ICMP_UGT:
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//
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// for (i = LB; i <= UB; ++i) { if (i > SV) A; else B; }
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//
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// is transformed into
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// AEV = SV;
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// BSV = SV + 1;
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// for (i = LB; i <= min(AEV, UB); ++i)
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// B;
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// for (i = max(LB, BSV); i <= UB; ++i)
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// A;
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BSV = BinaryOperator::createAdd(SD.SplitValue,
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ConstantInt::get(Ty, 1, Sign),
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"lsplit.add", PHTerminator);
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break;
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case ICmpInst::ICMP_SGE:
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case ICmpInst::ICMP_UGE:
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// ** TODO **
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//
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// for (i = LB; i <= UB; ++i) { if (i >= SV) A; else B; }
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//
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// is transformed into
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// AEV = SV - 1;
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// BSV = SV;
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// for (i = LB; i <= min(AEV, UB); ++i)
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// B;
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// for (i = max(LB, BSV); i <= UB; ++i)
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// A;
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AEV = BinaryOperator::createSub(SD.SplitValue,
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ConstantInt::get(Ty, 1, Sign),
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"lsplit.sub", PHTerminator);
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break;
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default:
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assert (0 && "Unexpected split condition predicate");
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break;
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} // end switch (SP)
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}
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break;
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}
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// Calculate ALoop induction variable's new exiting value and
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// BLoop induction variable's new starting value. Calculuate these
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// values in original loop's preheader.
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// A_ExitValue = min(SplitValue, OrignalLoopExitValue)
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// B_StartValue = max(SplitValue, OriginalLoopStartValue)
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if (isa<ConstantInt>(SD.SplitValue)) {
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SD.A_ExitValue = AEV;
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SD.B_StartValue = BSV;
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return;
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}
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Value *C1 = new ICmpInst(Sign ?
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ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT,
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AEV,
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ExitCondition->getOperand(ExitValueNum),
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"lsplit.ev", PHTerminator);
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SD.A_ExitValue = new SelectInst(C1, AEV,
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ExitCondition->getOperand(ExitValueNum),
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"lsplit.ev", PHTerminator);
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Value *C2 = new ICmpInst(Sign ?
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ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT,
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BSV, StartValue, "lsplit.sv",
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PHTerminator);
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SD.B_StartValue = new SelectInst(C2, StartValue, BSV,
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"lsplit.sv", PHTerminator);
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}
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/// splitLoop - Split current loop L in two loops using split information
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/// SD. Update dominator information. Maintain LCSSA form.
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bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
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@ -762,38 +984,11 @@ bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
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//
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// ALoop's exit edge enters BLoop's header through a forwarding block which
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// acts as a BLoop's preheader.
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BasicBlock *Preheader = L->getLoopPreheader();
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//[*] Calculate ALoop induction variable's new exiting value and
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// BLoop induction variable's new starting value. Calculuate these
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// values in original loop's preheader.
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// A_ExitValue = min(SplitValue, OrignalLoopExitValue)
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// B_StartValue = max(SplitValue, OriginalLoopStartValue)
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Value *A_ExitValue = NULL;
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Value *B_StartValue = NULL;
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if (isa<ConstantInt>(SD.SplitValue)) {
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A_ExitValue = SD.SplitValue;
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B_StartValue = SD.SplitValue;
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}
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else {
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BasicBlock *Preheader = L->getLoopPreheader();
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Instruction *PHTerminator = Preheader->getTerminator();
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bool SignedPredicate = ExitCondition->isSignedPredicate();
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Value *C1 = new ICmpInst(SignedPredicate ?
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ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT,
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SD.SplitValue,
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ExitCondition->getOperand(ExitValueNum),
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"lsplit.ev", PHTerminator);
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A_ExitValue = new SelectInst(C1, SD.SplitValue,
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ExitCondition->getOperand(ExitValueNum),
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"lsplit.ev", PHTerminator);
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Value *C2 = new ICmpInst(SignedPredicate ?
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ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT,
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SD.SplitValue, StartValue, "lsplit.sv",
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PHTerminator);
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B_StartValue = new SelectInst(C2, StartValue, SD.SplitValue,
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"lsplit.sv", PHTerminator);
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}
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// Calculate ALoop induction variable's new exiting value and
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// BLoop induction variable's new starting value.
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calculateLoopBounds(SD);
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//[*] Clone loop.
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DenseMap<const Value *, Value *> ValueMap;
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@ -815,7 +1010,7 @@ bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
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A_ExitInsn->setSuccessor(1, B_Header);
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//[*] Update ALoop's exit value using new exit value.
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ExitCondition->setOperand(ExitValueNum, A_ExitValue);
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ExitCondition->setOperand(ExitValueNum, SD.A_ExitValue);
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// [*] Update BLoop's header phi nodes. Remove incoming PHINode's from
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// original loop's preheader. Add incoming PHINode values from
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@ -831,7 +1026,7 @@ bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
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} else
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break;
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}
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BasicBlock *Preheader = L->getLoopPreheader();
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for (BasicBlock::iterator BI = B_Header->begin(), BE = B_Header->end();
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BI != BE; ++BI) {
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if (PHINode *PN = dyn_cast<PHINode>(BI)) {
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@ -840,7 +1035,7 @@ bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
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// Add incoming value from A_ExitingBlock.
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if (PN == B_IndVar)
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PN->addIncoming(B_StartValue, A_ExitingBlock);
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PN->addIncoming(SD.B_StartValue, A_ExitingBlock);
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else {
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PHINode *OrigPN = cast<PHINode>(InverseMap[PN]);
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Value *V2 = OrigPN->getIncomingValueForBlock(A_ExitingBlock);
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52
test/Transforms/LoopIndexSplit/SplitValue-2007-08-24.ll
Normal file
52
test/Transforms/LoopIndexSplit/SplitValue-2007-08-24.ll
Normal file
@ -0,0 +1,52 @@
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; Split loop. Save last value. Split value is off by one in this example.
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; RUN: llvm-as < %s | opt -loop-index-split -disable-output -stats |& \
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; RUN: grep "loop-index-split" | count 1
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@k = external global i32 ; <i32*> [#uses=2]
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define void @foobar(i32 %a, i32 %b) {
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entry:
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br label %bb
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bb: ; preds = %cond_next16, %entry
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%i.01.0 = phi i32 [ 0, %entry ], [ %tmp18, %cond_next16 ] ; <i32> [#uses=5]
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%tsum.18.0 = phi i32 [ 42, %entry ], [ %tsum.013.1, %cond_next16 ] ; <i32> [#uses=3]
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%tmp1 = icmp sgt i32 %i.01.0, 50 ; <i1> [#uses=1]
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br i1 %tmp1, label %cond_true, label %cond_false
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cond_true: ; preds = %bb
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%tmp4 = tail call i32 @foo( i32 %i.01.0 ) ; <i32> [#uses=1]
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%tmp6 = add i32 %tmp4, %tsum.18.0 ; <i32> [#uses=2]
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%tmp914 = load i32* @k, align 4 ; <i32> [#uses=1]
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%tmp1015 = icmp eq i32 %tmp914, 0 ; <i1> [#uses=1]
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br i1 %tmp1015, label %cond_next16, label %cond_true13
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cond_false: ; preds = %bb
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%tmp8 = tail call i32 @bar( i32 %i.01.0 ) ; <i32> [#uses=0]
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%tmp9 = load i32* @k, align 4 ; <i32> [#uses=1]
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%tmp10 = icmp eq i32 %tmp9, 0 ; <i1> [#uses=1]
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br i1 %tmp10, label %cond_next16, label %cond_true13
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cond_true13: ; preds = %cond_false, %cond_true
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%tsum.013.0 = phi i32 [ %tmp6, %cond_true ], [ %tsum.18.0, %cond_false ] ; <i32> [#uses=1]
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%tmp15 = tail call i32 @bar( i32 %i.01.0 ) ; <i32> [#uses=0]
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br label %cond_next16
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cond_next16: ; preds = %cond_false, %cond_true, %cond_true13
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%tsum.013.1 = phi i32 [ %tsum.013.0, %cond_true13 ], [ %tmp6, %cond_true ], [ %tsum.18.0, %cond_false ] ; <i32> [#uses=2]
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%tmp18 = add i32 %i.01.0, 1 ; <i32> [#uses=3]
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%tmp21 = icmp slt i32 %tmp18, 100 ; <i1> [#uses=1]
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br i1 %tmp21, label %bb, label %bb24
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bb24: ; preds = %cond_next16
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%tmp18.lcssa = phi i32 [ %tmp18, %cond_next16 ] ; <i32> [#uses=1]
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%tsum.013.1.lcssa = phi i32 [ %tsum.013.1, %cond_next16 ] ; <i32> [#uses=1]
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%tmp27 = tail call i32 @t( i32 %tmp18.lcssa, i32 %tsum.013.1.lcssa ) ; <i32> [#uses=0]
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ret void
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}
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declare i32 @foo(i32)
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declare i32 @bar(i32)
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declare i32 @t(i32, i32)
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