diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/optimizing/induction_var_analysis.cc | 8 | ||||
| -rw-r--r-- | compiler/optimizing/induction_var_range.cc | 8 |
2 files changed, 13 insertions, 3 deletions
diff --git a/compiler/optimizing/induction_var_analysis.cc b/compiler/optimizing/induction_var_analysis.cc index a1e1cde9df..82a898a9f1 100644 --- a/compiler/optimizing/induction_var_analysis.cc +++ b/compiler/optimizing/induction_var_analysis.cc @@ -552,9 +552,11 @@ void HInductionVarAnalysis::VisitCondition(HLoopInformation* loop, if (!IsExact(stride_expr, &stride_value)) { return; } - // Rewrite condition i != U into i < U or i > U if end condition is reached exactly. - if (cmp == kCondNE && ((stride_value == +1 && IsTaken(lower_expr, upper_expr, kCondLT)) || - (stride_value == -1 && IsTaken(lower_expr, upper_expr, kCondGT)))) { + // Rewrite condition i != U into strict end condition i < U or i > U if this end condition + // is reached exactly (tested by verifying if the loop has a unit stride and the non-strict + // condition would be always taken). + if (cmp == kCondNE && ((stride_value == +1 && IsTaken(lower_expr, upper_expr, kCondLE)) || + (stride_value == -1 && IsTaken(lower_expr, upper_expr, kCondGE)))) { cmp = stride_value > 0 ? kCondLT : kCondGT; } // Normalize a linear loop control with a nonzero stride: diff --git a/compiler/optimizing/induction_var_range.cc b/compiler/optimizing/induction_var_range.cc index b162696a42..f9b6910acd 100644 --- a/compiler/optimizing/induction_var_range.cc +++ b/compiler/optimizing/induction_var_range.cc @@ -216,6 +216,14 @@ bool InductionVarRange::IsConstant(HInductionVarAnalysis::InductionInfo* info, } } } while (RefineOuter(&v_min, &v_max)); + // Exploit array length + c >= c, with c <= 0 to avoid arithmetic wrap-around anomalies + // (e.g. array length == maxint and c == 1 would yield minint). + if (request == kAtLeast) { + if (v_min.a_constant == 1 && v_min.b_constant <= 0 && v_min.instruction->IsArrayLength()) { + *value = v_min.b_constant; + return true; + } + } } return false; } |