From 2f60ce21a061a3ebdd25b03717c1ace5ffee278f Mon Sep 17 00:00:00 2001
From: pyos <pyos@google.com>
Date: Wed, 26 May 2021 14:24:42 +0200
Subject: [PATCH] JVM: remove CHECKCAST handling from
 PopBackwardPropagationTransformer

Redundant CHECKCASTs should've been removed by a previous pass.
---
 .../PopBackwardPropagationTransformer.kt      | 32 ++++---------------
 1 file changed, 7 insertions(+), 25 deletions(-)

diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/PopBackwardPropagationTransformer.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/PopBackwardPropagationTransformer.kt
index 0c0489d42d7..3c63eab07a1 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/PopBackwardPropagationTransformer.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/PopBackwardPropagationTransformer.kt
@@ -60,7 +60,7 @@ class PopBackwardPropagationTransformer : MethodTransformer() {
                 if (insn.opcode == Opcodes.POP && frames[i] != null) {
                     val inputTop = getInputTop(insn)
                     val sources = inputTop.insns
-                    if (sources.all { !isDontTouch(it) } && sources.any { isTransformablePopOperand(it) }) {
+                    if (sources.none { isDontTouch(it) } && sources.any { isTransformablePopOperand(it) }) {
                         transformations[insn] = REPLACE_WITH_NOP
                         sources.forEach { propagatePopBackwards(it, inputTop.size) }
                     }
@@ -122,7 +122,7 @@ class PopBackwardPropagationTransformer : MethodTransformer() {
             }
 
             override fun unaryOperation(insn: AbstractInsnNode, value: SourceValue): SourceValue {
-                if (insn.opcode != Opcodes.CHECKCAST && !insn.isPrimitiveTypeConversion()) {
+                if (!insn.isPrimitiveTypeConversion()) {
                     value.insns.markAsDontTouch()
                 }
                 return super.unaryOperation(insn, value)
@@ -157,30 +157,16 @@ class PopBackwardPropagationTransformer : MethodTransformer() {
             if (transformations.containsKey(insn)) return
 
             when {
-                insn.opcode == Opcodes.CHECKCAST -> {
-                    val inputTop = getInputTop(insn)
-                    val sources = inputTop.insns
-                    val resultType = (insn as TypeInsnNode).desc
-                    if (sources.all { !isDontTouch(it) } && sources.any { isTransformableCheckcastOperand(it, resultType) }) {
-                        transformations[insn] = REPLACE_WITH_NOP
-                        sources.forEach { propagatePopBackwards(it, inputTop.size) }
-                    } else {
-                        transformations[insn] = insertPopAfterTransformation(poppedValueSize)
-                    }
-                }
-
-                insn.isPrimitiveBoxing() -> {
+                insn.isPrimitiveBoxing() ->
                     transformations[insn] = replaceWithPopTransformation(getInputTop(insn).size)
-                }
 
-                insn.isPurePush() -> {
+                insn.isPurePush() ->
                     transformations[insn] = REPLACE_WITH_NOP
-                }
 
                 insn.isPrimitiveTypeConversion() -> {
                     val inputTop = getInputTop(insn)
                     val sources = inputTop.insns
-                    if (sources.all { !isDontTouch(it) }) {
+                    if (sources.none { isDontTouch(it) }) {
                         transformations[insn] = REPLACE_WITH_NOP
                         sources.forEach { propagatePopBackwards(it, inputTop.size) }
                     } else {
@@ -188,9 +174,8 @@ class PopBackwardPropagationTransformer : MethodTransformer() {
                     }
                 }
 
-                else -> {
+                else ->
                     transformations[insn] = insertPopAfterTransformation(poppedValueSize)
-                }
             }
         }
 
@@ -214,11 +199,8 @@ class PopBackwardPropagationTransformer : MethodTransformer() {
             return frame.top() ?: throw AssertionError("Instruction #$i has empty stack on input")
         }
 
-        private fun isTransformableCheckcastOperand(it: AbstractInsnNode, resultType: String) =
-            it.isPrimitiveBoxing() && (it as MethodInsnNode).owner == resultType
-
         private fun isTransformablePopOperand(insn: AbstractInsnNode) =
-            insn.opcode == Opcodes.CHECKCAST || insn.isPrimitiveBoxing() || insn.isPurePush()
+            insn.isPrimitiveBoxing() || insn.isPurePush()
 
         private fun isDontTouch(insn: AbstractInsnNode) =
             dontTouchInsnIndices[insnList.indexOf(insn)]