Fix min/max SIMD reduction
Use HVecReplicateScalar instead of HVecSetScalars when creating an
initial vector for min/max. This way we are preventing that zeroes
from the initial vector are taken into account for min/max
calculations. Otherwise, min(MAX_INT, x[0],.., x[n-1]) = 0 if each
x[i] is positive which is incorrect.
Added regression test cases in 661-checker-simd-reduc.
Test: ./testrunner.py --target --optimizing in QEMU (arm64)
Change-Id: I1779eefc7f2ab9971dec561b2e1fbf262652410e
diff --git a/compiler/optimizing/loop_optimization.cc b/compiler/optimizing/loop_optimization.cc
index 645915e..69c6b94 100644
--- a/compiler/optimizing/loop_optimization.cc
+++ b/compiler/optimizing/loop_optimization.cc
@@ -1623,17 +1623,28 @@
}
// Prepare the new initialization.
if (vector_mode_ == kVector) {
- // Generate a [initial, 0, .., 0] vector.
+ // Generate a [initial, 0, .., 0] vector for add or
+ // a [initial, initial, .., initial] vector for min/max.
HVecOperation* red_vector = new_red->AsVecOperation();
+ HVecReduce::ReductionKind kind = GetReductionKind(red_vector);
size_t vector_length = red_vector->GetVectorLength();
DataType::Type type = red_vector->GetPackedType();
- new_init = Insert(vector_preheader_,
- new (global_allocator_) HVecSetScalars(global_allocator_,
- &new_init,
- type,
- vector_length,
- 1,
- kNoDexPc));
+ if (kind == HVecReduce::ReductionKind::kSum) {
+ new_init = Insert(vector_preheader_,
+ new (global_allocator_) HVecSetScalars(global_allocator_,
+ &new_init,
+ type,
+ vector_length,
+ 1,
+ kNoDexPc));
+ } else {
+ new_init = Insert(vector_preheader_,
+ new (global_allocator_) HVecReplicateScalar(global_allocator_,
+ new_init,
+ type,
+ vector_length,
+ kNoDexPc));
+ }
} else {
new_init = ReduceAndExtractIfNeeded(new_init);
}