Fix transfer over rejected induction.
Rationale:
With the more precise rejection of narrowing
linear induction, parent rules should be
prepared to reject failed transfers. Also
added a bit more comments to clarify rules.
With regression tests.
Bug: 33774618
Test: test-art-host
Change-Id: I4a206e51d4359ab383379914dd4697fc81903547
diff --git a/compiler/optimizing/induction_var_analysis.cc b/compiler/optimizing/induction_var_analysis.cc
index 5456b1e..88473f02 100644
--- a/compiler/optimizing/induction_var_analysis.cc
+++ b/compiler/optimizing/induction_var_analysis.cc
@@ -431,16 +431,17 @@
if (IsNarrowingLinear(a) || IsNarrowingLinear(b)) {
return nullptr; // no transfer
} else if (a->induction_class == kInvariant && b->induction_class == kInvariant) {
- return CreateInvariantOp(op, a, b);
+ return CreateInvariantOp(op, a, b); // direct invariant
} else if ((a->induction_class == kLinear && b->induction_class == kLinear) ||
(a->induction_class == kPolynomial && b->induction_class == kPolynomial)) {
- return CreateInduction(a->induction_class,
- a->operation,
- TransferAddSub(a->op_a, b->op_a, op),
- TransferAddSub(a->op_b, b->op_b, op),
- /*fetch*/ nullptr,
- type_);
+ // Rule induc(a, b) + induc(a', b') -> induc(a + a', b + b').
+ InductionInfo* new_a = TransferAddSub(a->op_a, b->op_a, op);
+ InductionInfo* new_b = TransferAddSub(a->op_b, b->op_b, op);
+ if (new_a != nullptr && new_b != nullptr) {
+ return CreateInduction(a->induction_class, a->operation, new_a, new_b, a->fetch, type_);
+ }
} else if (a->induction_class == kInvariant) {
+ // Rule a + induc(a', b') -> induc(a', a + b') or induc(a + a', a + b').
InductionInfo* new_a = b->op_a;
InductionInfo* new_b = TransferAddSub(a, b->op_b, op);
if (b->induction_class == kWrapAround || b->induction_class == kPeriodic) {
@@ -448,14 +449,19 @@
} else if (op == kSub) { // Negation required.
new_a = TransferNeg(new_a);
}
- return CreateInduction(b->induction_class, b->operation, new_a, new_b, b->fetch, type_);
+ if (new_a != nullptr && new_b != nullptr) {
+ return CreateInduction(b->induction_class, b->operation, new_a, new_b, b->fetch, type_);
+ }
} else if (b->induction_class == kInvariant) {
+ // Rule induc(a, b) + b' -> induc(a, b + b') or induc(a + b', b + b').
InductionInfo* new_a = a->op_a;
InductionInfo* new_b = TransferAddSub(a->op_b, b, op);
if (a->induction_class == kWrapAround || a->induction_class == kPeriodic) {
new_a = TransferAddSub(new_a, b, op);
}
- return CreateInduction(a->induction_class, a->operation, new_a, new_b, a->fetch, type_);
+ if (new_a != nullptr && new_b != nullptr) {
+ return CreateInduction(a->induction_class, a->operation, new_a, new_b, a->fetch, type_);
+ }
}
}
return nullptr;
@@ -468,14 +474,14 @@
if (IsNarrowingLinear(a)) {
return nullptr; // no transfer
} else if (a->induction_class == kInvariant) {
- return CreateInvariantOp(kNeg, nullptr, a);
+ return CreateInvariantOp(kNeg, nullptr, a); // direct invariant
} else if (a->induction_class != kGeometric || a->operation == kMul) {
- return CreateInduction(a->induction_class,
- a->operation,
- TransferNeg(a->op_a),
- TransferNeg(a->op_b),
- a->fetch,
- type_);
+ // Rule - induc(a, b) -> induc(-a, -b).
+ InductionInfo* new_a = TransferNeg(a->op_a);
+ InductionInfo* new_b = TransferNeg(a->op_b);
+ if (new_a != nullptr && new_b != nullptr) {
+ return CreateInduction(a->induction_class, a->operation, new_a, new_b, a->fetch, type_);
+ }
}
}
return nullptr;
@@ -490,23 +496,23 @@
if (IsNarrowingLinear(a) || IsNarrowingLinear(b)) {
return nullptr; // no transfer
} else if (a->induction_class == kInvariant && b->induction_class == kInvariant) {
- return CreateInvariantOp(kMul, a, b);
+ return CreateInvariantOp(kMul, a, b); // direct invariant
} else if (a->induction_class == kInvariant && (b->induction_class != kGeometric ||
b->operation == kMul)) {
- return CreateInduction(b->induction_class,
- b->operation,
- TransferMul(a, b->op_a),
- TransferMul(a, b->op_b),
- b->fetch,
- type_);
+ // Rule a * induc(a', b') -> induc(a * a', b * b').
+ InductionInfo* new_a = TransferMul(a, b->op_a);
+ InductionInfo* new_b = TransferMul(a, b->op_b);
+ if (new_a != nullptr && new_b != nullptr) {
+ return CreateInduction(b->induction_class, b->operation, new_a, new_b, b->fetch, type_);
+ }
} else if (b->induction_class == kInvariant && (a->induction_class != kGeometric ||
a->operation == kMul)) {
- return CreateInduction(a->induction_class,
- a->operation,
- TransferMul(a->op_a, b),
- TransferMul(a->op_b, b),
- a->fetch,
- type_);
+ // Rule induc(a, b) * b' -> induc(a * b', b * b').
+ InductionInfo* new_a = TransferMul(a->op_a, b);
+ InductionInfo* new_b = TransferMul(a->op_b, b);
+ if (new_a != nullptr && new_b != nullptr) {
+ return CreateInduction(a->induction_class, a->operation, new_a, new_b, a->fetch, type_);
+ }
}
}
return nullptr;
@@ -522,7 +528,7 @@
if (IsNarrowingIntegralConversion(from, to) &&
a->induction_class == kLinear &&
(a->type == to || IsNarrowingIntegralConversion(a->type, to))) {
- return CreateInduction(kLinear, kNop, a->op_a, a->op_b, /*fetch*/ nullptr, to);
+ return CreateInduction(kLinear, kNop, a->op_a, a->op_b, a->fetch, to);
}
}
return nullptr;
@@ -600,17 +606,15 @@
return CreateInvariantOp(op, a, b);
}
}
- } else if (b->induction_class == kLinear) {
+ } else if (b->induction_class == kLinear && b->type == type_) {
// Solve within a tight cycle that adds a term that is already classified as a linear
// induction for a polynomial induction k = k + i (represented as sum over linear terms).
if (x == entry_phi && entry_phi->InputCount() == 2 && instruction == entry_phi->InputAt(1)) {
InductionInfo* initial = LookupInfo(loop, entry_phi->InputAt(0));
- return CreateInduction(kPolynomial,
- kNop,
- op == kAdd ? b : TransferNeg(b),
- initial,
- /*fetch*/ nullptr,
- type_);
+ InductionInfo* new_a = op == kAdd ? b : TransferNeg(b);
+ if (new_a != nullptr) {
+ return CreateInduction(kPolynomial, kNop, new_a, initial, /*fetch*/ nullptr, type_);
+ }
}
}
}
diff --git a/test/623-checker-loop-regressions/src/Main.java b/test/623-checker-loop-regressions/src/Main.java
index ce5bda1..7cc0b8b 100644
--- a/test/623-checker-loop-regressions/src/Main.java
+++ b/test/623-checker-loop-regressions/src/Main.java
@@ -82,6 +82,88 @@
return 0;
}
+ // Regression test for b/33774618: transfer operations involving
+ // narrowing linear induction should be done correctly.
+ //
+ /// CHECK-START: int Main.transferNarrowWrap() loop_optimization (before)
+ /// CHECK-DAG: Phi loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ //
+ /// CHECK-START: int Main.transferNarrowWrap() loop_optimization (after)
+ /// CHECK-DAG: Phi loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ static int transferNarrowWrap() {
+ short x = 0;
+ int w = 10;
+ int v = 3;
+ for (int i = 0; i < 10; i++) {
+ v = w + 1; // transfer on wrap-around
+ w = x; // wrap-around
+ x += 2; // narrowing linear
+ }
+ return v;
+ }
+
+ // Regression test for b/33774618: transfer operations involving
+ // narrowing linear induction should be done correctly
+ // (currently rejected, could be improved).
+ //
+ /// CHECK-START: int Main.polynomialShort() loop_optimization (before)
+ /// CHECK-DAG: Phi loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ //
+ /// CHECK-START: int Main.polynomialShort() loop_optimization (after)
+ /// CHECK-DAG: Phi loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ static int polynomialShort() {
+ int x = 0;
+ for (short i = 0; i < 10; i++) {
+ x = x - i; // polynomial on narrowing linear
+ }
+ return x;
+ }
+
+ // Regression test for b/33774618: transfer operations involving
+ // narrowing linear induction should be done correctly
+ // (currently rejected, could be improved).
+ //
+ /// CHECK-START: int Main.polynomialIntFromLong() loop_optimization (before)
+ /// CHECK-DAG: Phi loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ //
+ /// CHECK-START: int Main.polynomialIntFromLong() loop_optimization (after)
+ /// CHECK-DAG: Phi loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ static int polynomialIntFromLong() {
+ int x = 0;
+ for (long i = 0; i < 10; i++) {
+ x = x - (int) i; // polynomial on narrowing linear
+ }
+ return x;
+ }
+
+ /// CHECK-START: int Main.polynomialInt() loop_optimization (before)
+ /// CHECK-DAG: Phi loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none
+ //
+ /// CHECK-START: int Main.polynomialInt() loop_optimization (after)
+ /// CHECK-NOT: Phi
+ //
+ /// CHECK-START: int Main.polynomialInt() instruction_simplifier$after_bce (after)
+ /// CHECK-DAG: <<Int:i\d+>> IntConstant -45 loop:none
+ /// CHECK-DAG: Return [<<Int>>] loop:none
+ static int polynomialInt() {
+ int x = 0;
+ for (int i = 0; i < 10; i++) {
+ x = x - i;
+ }
+ return x;
+ }
+
public static void main(String[] args) {
expectEquals(10, earlyExitFirst(-1));
for (int i = 0; i <= 10; i++) {
@@ -98,6 +180,11 @@
expectEquals(2, earlyExitNested());
+ expectEquals(17, transferNarrowWrap());
+ expectEquals(-45, polynomialShort());
+ expectEquals(-45, polynomialIntFromLong());
+ expectEquals(-45, polynomialInt());
+
System.out.println("passed");
}
