diff options
| -rw-r--r-- | compiler/optimizing/induction_var_range.cc | 12 | ||||
| -rw-r--r-- | test/618-checker-induction/src/Main.java | 37 | ||||
| -rw-r--r-- | test/654-checker-periodic/src/Main.java | 44 |
3 files changed, 92 insertions, 1 deletions
diff --git a/compiler/optimizing/induction_var_range.cc b/compiler/optimizing/induction_var_range.cc index b1f33abdf8..b54507a03c 100644 --- a/compiler/optimizing/induction_var_range.cc +++ b/compiler/optimizing/induction_var_range.cc @@ -1359,6 +1359,15 @@ bool InductionVarRange::GenerateLastValuePeriodic(const HBasicBlock* context, HInstruction* x = nullptr; HInstruction* y = nullptr; HInstruction* t = nullptr; + + // Overflows when the stride is equal to `1` are fine since the periodicity is + // `2` and the lowest bit is the same. Similar with `-1`. + auto allow_potential_overflow = [&]() { + int64_t stride_value = 0; + return IsConstant(context, loop, trip->op_a->op_b, kExact, &stride_value) && + (stride_value == 1 || stride_value == -1); + }; + if (period == 2 && GenerateCode(context, loop, @@ -1383,7 +1392,8 @@ bool InductionVarRange::GenerateLastValuePeriodic(const HBasicBlock* context, graph, block, /*is_min=*/ false, - graph ? &t : nullptr)) { + graph ? &t : nullptr, + allow_potential_overflow())) { // During actual code generation (graph != nullptr), generate is_even ? x : y. if (graph != nullptr) { DataType::Type type = trip->type; diff --git a/test/618-checker-induction/src/Main.java b/test/618-checker-induction/src/Main.java index 21cca22dd3..bcd545cd85 100644 --- a/test/618-checker-induction/src/Main.java +++ b/test/618-checker-induction/src/Main.java @@ -672,6 +672,40 @@ public class Main { return k; } + /// CHECK-START: int Main.periodicOverflowTripCountNotOptimized() loop_optimization (before) + /// CHECK-DAG: <<Phi1:i\d+>> Phi loop:<<Loop:B\d+>> outer_loop:none + /// CHECK-DAG: {{i\d+}} Phi loop:<<Loop>> outer_loop:none + /// CHECK-DAG: Return [<<Phi1>>] loop:none + // + /// CHECK-START: int Main.periodicOverflowTripCountNotOptimized() loop_optimization (after) + /// CHECK-DAG: <<Phi1:i\d+>> Phi loop:<<Loop:B\d+>> outer_loop:none + /// CHECK-DAG: {{i\d+}} Phi loop:<<Loop>> outer_loop:none + /// CHECK-DAG: Return [<<Phi1>>] loop:none + static int periodicOverflowTripCountNotOptimized() { + int k = 0; + for (int i = Integer.MIN_VALUE; i < Integer.MAX_VALUE - 81; i += 80) { + k = 1 - k; + } + return k; + } + + /// CHECK-START: int Main.periodicCouldOverflowTripCountNotOptimized(int) loop_optimization (before) + /// CHECK-DAG: <<Phi1:i\d+>> Phi loop:<<Loop:B\d+>> outer_loop:none + /// CHECK-DAG: {{i\d+}} Phi loop:<<Loop>> outer_loop:none + /// CHECK-DAG: Return [<<Phi1>>] loop:none + // + /// CHECK-START: int Main.periodicCouldOverflowTripCountNotOptimized(int) loop_optimization (after) + /// CHECK-DAG: <<Phi1:i\d+>> Phi loop:<<Loop:B\d+>> outer_loop:none + /// CHECK-DAG: {{i\d+}} Phi loop:<<Loop>> outer_loop:none + /// CHECK-DAG: Return [<<Phi1>>] loop:none + static int periodicCouldOverflowTripCountNotOptimized(int start) { + int k = 0; + for (int i = start; i < Integer.MAX_VALUE - 81; i += 80) { + k = 1 - k; + } + return k; + } + // If ever replaced by closed form, last value should be correct! private static int getSumN(int n) { int k = 0; @@ -1138,6 +1172,9 @@ public class Main { expectEquals((tc * (tc + 1)) / 2, getSumN(n)); } + expectEquals(1, periodicOverflowTripCountNotOptimized()); + expectEquals(1, periodicCouldOverflowTripCountNotOptimized(Integer.MIN_VALUE)); + expectEquals(10, closedTwice()); expectEquals(20, closedFeed()); expectEquals(-10, closedLargeUp()); diff --git a/test/654-checker-periodic/src/Main.java b/test/654-checker-periodic/src/Main.java index 7a0c98cfae..0ae0b31841 100644 --- a/test/654-checker-periodic/src/Main.java +++ b/test/654-checker-periodic/src/Main.java @@ -50,6 +50,21 @@ public class Main { return lI; } + /// CHECK-START: int Main.doitDownInt2(int) loop_optimization (before) + /// CHECK-DAG: <<Phi:i\d+>> Phi loop:<<Loop:B\d+>> outer_loop:none + /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none + // + /// CHECK-START: int Main.doitDownInt2(int) loop_optimization (after) + /// CHECK-NOT: Phi + static int doitDownInt2(int n) { + // Complete loop is replaced by last-value. + int lI = 1; + for (int i1 = n; i1 > 0; i1--) { + lI = (1486662021 - lI); + } + return lI; + } + /// CHECK-START: float Main.doitUpFloat(int) loop_optimization (before) /// CHECK-DAG: <<Phi:i\d+>> Phi loop:<<Loop:B\d+>> outer_loop:none /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none @@ -122,6 +137,25 @@ public class Main { return lF; } + /// CHECK-START: float Main.doitDownFloatAlt2(int) loop_optimization (before) + /// CHECK-DAG: <<Phi:i\d+>> Phi loop:<<Loop:B\d+>> outer_loop:none + /// CHECK-DAG: Phi loop:<<Loop>> outer_loop:none + // + /// CHECK-START: float Main.doitDownFloatAlt2(int) loop_optimization (after) + /// CHECK-NOT: Phi + static float doitDownFloatAlt2(int n) { + // Complete loop is replaced by last-value + // since the values are now precise. + float lF = 1.0f; + float l2 = 1486662020.0f; + for (int i1 = n; i1 > 0; i1--) { + float old = lF; + lF = l2; + l2 = old; + } + return lF; + } + // Main driver. public static void main(String[] args) { for (int i = 0; i < 10; i++) { @@ -135,6 +169,11 @@ public class Main { expectEquals(ei, ci); } for (int i = 0; i < 10; i++) { + int ei = (i & 1) == 0 ? 1 : 1486662020; + int ci = doitDownInt2(i); + expectEquals(ei, ci); + } + for (int i = 0; i < 10; i++) { float ef = i == 0 ? 1.0f : ((i & 1) == 0 ? 0.0f : 1486662021.0f); float cf = doitUpFloat(i); expectEquals(ef, cf); @@ -154,6 +193,11 @@ public class Main { float cf = doitDownFloatAlt(i); expectEquals(ef, cf); } + for (int i = 0; i < 10; i++) { + float ef = (i & 1) == 0 ? 1.0f : 1486662020.0f; + float cf = doitDownFloatAlt2(i); + expectEquals(ef, cf); + } System.out.println("passed"); } |