JVM_IR KT-48640 generate for-in-downTo as a counter loop

This commit is contained in:
Dmitry Petrov
2021-09-21 17:55:13 +03:00
committed by TeamCityServer
parent 42e8017cc7
commit 2cc6b589f3
16 changed files with 262 additions and 32 deletions
@@ -0,0 +1,36 @@
// IGNORE_BACKEND_FIR: JVM_IR
// IMPORTANT!
// Please, when your changes cause failures in bytecodeText tests for 'for' loops,
// examine the resulting bytecode shape carefully.
// Range and progression-based loops generated with Kotlin compiler should be
// as close as possible to Java counter loops ('for (int i = a; i < b; ++i) { ... }').
// Otherwise it may result in performance regression due to missing HotSpot optimizations.
// Run Kotlin compiler benchmarks (https://github.com/Kotlin/kotlin-benchmarks)
// with compiler built from your changes if you are not sure.
const val M = 1L
fun f(a: Long): Int {
var n = 0
for (i in a downTo M) {
n++
}
return n
}
// 0 iterator
// 0 getStart
// 0 getEnd
// 0 getFirst
// 0 getLast
// 0 getStep
// 1 LCMP
// 1 IF
// JVM_IR_TEMPLATES
// 1 ILOAD
// 1 ISTORE
// 0 IADD
// 0 ISUB
// 1 IINC
@@ -24,8 +24,8 @@ fun test(): Int {
// 1 IF
// JVM_IR_TEMPLATES
// 5 ILOAD
// 4 ISTORE
// 4 ILOAD
// 3 ISTORE
// 1 IADD
// 0 ISUB
// 1 IINC