MIPS32R2: Share address computation
For array accesses the element address has the following structure:
Address = CONST_OFFSET + base_addr + index << ELEM_SHIFT
The address part (index << ELEM_SHIFT) can be shared across array
accesses with the same data type and index.
For example, in the following loop 5 accesses can share address
computation:
void foo(int[] a, int[] b, int[] c) {
for (i...) {
a[i] = a[i] + 5;
b[i] = b[i] + c[i];
}
}
Test: test-art-host, test-art-target
Change-Id: Id09fa782934aad4ee47669275e7e1a4d7d23b0fa
diff --git a/compiler/optimizing/nodes_mips.h b/compiler/optimizing/nodes_mips.h
index 80e652e..ef388c3 100644
--- a/compiler/optimizing/nodes_mips.h
+++ b/compiler/optimizing/nodes_mips.h
@@ -69,6 +69,46 @@
DISALLOW_COPY_AND_ASSIGN(HMipsPackedSwitch);
};
+// This instruction computes part of the array access offset (index offset).
+//
+// For array accesses the element address has the following structure:
+// Address = CONST_OFFSET + base_addr + index << ELEM_SHIFT. The address part
+// (index << ELEM_SHIFT) can be shared across array accesses with
+// the same data type and index. For example, in the following loop 5 accesses can share address
+// computation:
+//
+// void foo(int[] a, int[] b, int[] c) {
+// for (i...) {
+// a[i] = a[i] + 5;
+// b[i] = b[i] + c[i];
+// }
+// }
+//
+// Note: as the instruction doesn't involve base array address into computations it has no side
+// effects.
+class HIntermediateArrayAddressIndex FINAL : public HExpression<2> {
+ public:
+ HIntermediateArrayAddressIndex(HInstruction* index, HInstruction* shift, uint32_t dex_pc)
+ : HExpression(DataType::Type::kInt32, SideEffects::None(), dex_pc) {
+ SetRawInputAt(0, index);
+ SetRawInputAt(1, shift);
+ }
+
+ bool CanBeMoved() const OVERRIDE { return true; }
+ bool InstructionDataEquals(const HInstruction* other ATTRIBUTE_UNUSED) const OVERRIDE {
+ return true;
+ }
+ bool IsActualObject() const OVERRIDE { return false; }
+
+ HInstruction* GetIndex() const { return InputAt(0); }
+ HInstruction* GetShift() const { return InputAt(1); }
+
+ DECLARE_INSTRUCTION(IntermediateArrayAddressIndex);
+
+ private:
+ DISALLOW_COPY_AND_ASSIGN(HIntermediateArrayAddressIndex);
+};
+
} // namespace art
#endif // ART_COMPILER_OPTIMIZING_NODES_MIPS_H_