Fix last value generation in loop optimization.

Instead of `in_body`, propagate the context block and loop
information to make better decisions for trip count if the
context is outside the loop.

In particular, fix `InductionVarRange::IsConstant()` to take
and use this information instead of assuming that we are
asking about values in the loop body.

For trip count with context outside the loop, we know that
the value shall be the maximum trip count if the context
is dominated by the loop control exit block.

Test: Enable run-test 835-b216762268.
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 216762268
Change-Id: Id564ba75c812d54abdd9b229e643cc8ab4701c52

1 files changed, 2 insertions, 2 deletions

diff --git a/compiler/optimizing/loop_optimization.cc b/compiler/optimizing/loop_optimization.cc
index 9e298a5418..77dfe68bf6 100644
--- a/compiler/optimizing/loop_optimization.cc
+++ b/compiler/optimizing/loop_optimization.cc
@@ -1331,7 +1331,7 @@ bool HLoopOptimization::VectorizeDef(LoopNode* node,
     }
     if (TrySetVectorType(type, &restrictions) &&
         node->loop_info->IsDefinedOutOfTheLoop(base) &&
-        induction_range_.IsUnitStride(instruction, index, graph_, &offset) &&
+        induction_range_.IsUnitStride(instruction->GetBlock(), index, graph_, &offset) &&
         VectorizeUse(node, value, generate_code, type, restrictions)) {
       if (generate_code) {
         GenerateVecSub(index, offset);
@@ -1412,7 +1412,7 @@ bool HLoopOptimization::VectorizeUse(LoopNode* node,
     HInstruction* offset = nullptr;
     if (HVecOperation::ToSignedType(type) == HVecOperation::ToSignedType(instruction->GetType()) &&
         node->loop_info->IsDefinedOutOfTheLoop(base) &&
-        induction_range_.IsUnitStride(instruction, index, graph_, &offset)) {
+        induction_range_.IsUnitStride(instruction->GetBlock(), index, graph_, &offset)) {
       if (generate_code) {
         GenerateVecSub(index, offset);
         GenerateVecMem(instruction, vector_map_->Get(index), nullptr, offset, type);