ARM: Optimize Div/Rem by 2^n for non-negative dividends
When it can be proved that dividends are non-negative or the min integer
if their type is integral, there is no need to generate instructions
correcting the result.
The CL implements this optimization for ARM32/ARM64.
Test: 411-checker-hdiv-hrem-pow2
Test: test.py --host --optimizing --jit --gtest --interpreter
Test: test.py -target --optimizing --jit --interpreter
Test: run-gtests.sh
Change-Id: I11211a42918b5801fce8e78f305e69549739c23c
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index ec4b79e..64e62fd 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -3173,4 +3173,22 @@
resolved_method_ = method;
}
+bool IsGEZero(HInstruction* instruction) {
+ DCHECK(instruction != nullptr);
+ if (instruction->IsArrayLength()) {
+ return true;
+ } else if (instruction->IsMin()) {
+ // Instruction MIN(>=0, >=0) is >= 0.
+ return IsGEZero(instruction->InputAt(0)) &&
+ IsGEZero(instruction->InputAt(1));
+ } else if (instruction->IsAbs()) {
+ // Instruction ABS(>=0) is >= 0.
+ // NOTE: ABS(minint) = minint prevents assuming
+ // >= 0 without looking at the argument.
+ return IsGEZero(instruction->InputAt(0));
+ }
+ int64_t value = -1;
+ return IsInt64AndGet(instruction, &value) && value >= 0;
+}
+
} // namespace art