ForLoopsLowering: Assume step == 1 for *Range (e.g., IntRange) and

handle accordingly (e.g., do not read `step` property).

compiler/testData/codegen/bytecodeText/forLoop/primitiveRange.kt

@@ -7,4 +7,5 @@ fun f(r: IntRange) {
 // 0 getStart
 // 0 getEnd
 // 1 getFirst
-// 1 getLast
+// 1 getLast
+// 0 getStep

compiler/testData/codegen/bytecodeText/forLoop/stepped/stepConstOnNonLiteralProgression.kt

@@ -1,6 +1,6 @@
 // TARGET_BACKEND: JVM_IR
 fun box(): String {
-    val intProgression = 1..7
+    val intProgression = 1..7 step 3  // `step` ensures type is IntProgression, NOT IntRange
     for (i in intProgression step 2) {
     }
 
@@ -15,10 +15,9 @@ fun box(): String {
 // Expected lowered form of loop:
 //
 //   // Additional statements:
-//   val progression = intProgression
-//   val nestedFirst = progression.first
-//   val nestedLast = progression.last
-//   val nestedStep = progression.step
+//   val nestedFirst = intProgression.first
+//   val nestedLast = intProgression.last
+//   val nestedStep = intProgression.step
 //   val maybeNegatedStep = if (nestedStep <= 0) -2 else 2
 //
 //   // Standard form of loop over progression

compiler/testData/codegen/bytecodeText/forLoop/stepped/stepNonConstOnNonLiteralProgression.kt

@@ -2,7 +2,7 @@
 fun one() = 1
 
 fun box(): String {
-    val intProgression = 1..7
+    val intProgression = 1..7 step 3  // `step` ensures type is IntProgression, NOT IntRange
     for (i in intProgression step one()) {
     }
 
@@ -16,10 +16,9 @@ fun box(): String {
 // Expected lowered form of loop:
 //
 //   // Additional statements:
-//   val progression = intProgression
-//   val nestedFirst = progression.first
-//   val nestedLast = progression.last
-//   val nestedStep = progression.step
+//   val nestedFirst = intProgression.first
+//   val nestedLast = intProgression.last
+//   val nestedStep = intProgression.step
 //   var stepArg = one()
 //   if (stepArg <= 0) throw IllegalArgumentException("Step must be positive, was: $stepArg.")
 //   if (nestedStep <= 0) stepArg = -stepArg

compiler/testData/codegen/bytecodeText/forLoop/stepped/stepOnNonLiteralRange.kt

@@ -0,0 +1,45 @@
+// TARGET_BACKEND: JVM_IR
+fun box(): String {
+    val intRange = 1..7
+    for (i in intRange step 2) {
+    }
+
+    return "OK"
+}
+
+// For "step" progressions in JVM IR, a call to getProgressionLastElement() is made to compute the "last" value.
+// If "step" is called on a non-literal progression, there is a check to see if that progression's step value is < 0.
+// However, if the progression is of type *Range (e.g., IntRange) instead of *Progression (e.g., IntProgression), this
+// check is not needed since *Range always has step == 1.
+//
+// Expected lowered form of loop:
+//
+//   // Additional statements:
+//   val nestedFirst = intRange.first
+//   val nestedLast = intRange.last
+//
+//   // Standard form of loop over progression
+//   var inductionVar = nestedFirst
+//   val last = getProgressionLastElement(nestedFirst, nestedLast, 2)
+//   if (inductionVar <= last) {
+//     // Loop is not empty
+//     do {
+//       val i = inductionVar
+//       inductionVar += 2
+//       // Loop body
+//     } while (i != last)
+//   }
+
+// 0 iterator
+// 0 getStart
+// 0 getEnd
+// 1 getFirst
+// 1 getLast
+// 0 getStep
+// 1 INVOKESTATIC kotlin/internal/ProgressionUtilKt.getProgressionLastElement
+// 0 NEW java/lang/IllegalArgumentException
+// 0 ATHROW
+// 1 IF_ICMPGT
+// 1 IF_ICMPNE
+// 2 IF
+// 0 INEG

compiler/testData/codegen/bytecodeText/forLoop/unsigned/stepConstOnNonLiteralProgression.kt

@@ -1,7 +1,7 @@
 // TARGET_BACKEND: JVM_IR
 // WITH_RUNTIME
 fun box(): String {
-    val uintProgression = 1u..7u
+    val uintProgression = 1u..7u step 3  // `step` ensures type is UIntProgression, NOT UIntRange
     for (i in uintProgression step 2) {
     }
 
@@ -16,10 +16,9 @@ fun box(): String {
 // Expected lowered form of loop:
 //
 //   // Additional statements:
-//   val progression = intProgression
-//   val nestedFirst = progression.first
-//   val nestedLast = progression.last
-//   val nestedStep = progression.step
+//   val nestedFirst = uintProgression.first
+//   val nestedLast = uintProgression.last
+//   val nestedStep = uintProgression.step
 //   val maybeNegatedStep = if (nestedStep <= 0) -2 else 2
 //
 //   // Standard form of loop over progression

compiler/testData/codegen/bytecodeText/forLoop/unsigned/stepNonConstOnNonLiteralProgression.kt

@@ -3,7 +3,7 @@
 fun one() = 1
 
 fun box(): String {
-    val uintProgression = 1u..7u
+    val uintProgression = 1u..7u step 3  // `step` ensures type is UIntProgression, NOT UIntRange
     for (i in uintProgression step one()) {
     }
 
@@ -17,10 +17,9 @@ fun box(): String {
 // Expected lowered form of loop:
 //
 //   // Additional statements:
-//   val progression = intProgression
-//   val nestedFirst = progression.first
-//   val nestedLast = progression.last
-//   val nestedStep = progression.step
+//   val nestedFirst = uintProgression.first
+//   val nestedLast = uintProgression.last
+//   val nestedStep = uintProgression.step
 //   var stepArg = one()
 //   if (stepArg <= 0) throw IllegalArgumentException("Step must be positive, was: $stepArg.")
 //   if (nestedStep <= 0) stepArg = -stepArg

compiler/testData/codegen/bytecodeText/forLoop/unsigned/stepOnNonLiteralRange.kt

@@ -0,0 +1,49 @@
+// TARGET_BACKEND: JVM_IR
+// WITH_RUNTIME
+fun box(): String {
+    val uintRange = 1u..7u
+    for (i in uintRange step 2) {
+    }
+
+    return "OK"
+}
+
+// For "step" progressions in JVM IR, a call to getProgressionLastElement() is made to compute the "last" value.
+// If "step" is called on a non-literal progression, there is a check to see if that progression's step value is < 0.
+// However, if the progression is of type *Range (e.g., IntRange) instead of *Progression (e.g., IntProgression), this
+// check is not needed since *Range always has step == 1.
+//
+// Expected lowered form of loop:
+//
+//   // Additional statements:
+//   val nestedFirst = uintRange.first
+//   val nestedLast = uintRange.last
+//
+//   // Standard form of loop over progression
+//   var inductionVar = nestedFirst
+//   val last = getProgressionLastElement(nestedFirst, nestedLast, 2)
+//   if (inductionVar <= last) {
+//     // Loop is not empty
+//     do {
+//       val i = inductionVar
+//       inductionVar += 2
+//       // Loop body
+//     } while (i != last)
+//   }
+
+// 0 iterator
+// 0 getStart
+// 0 getEnd
+// 1 getFirst
+// 1 getLast
+// 0 getStep
+// 1 INVOKESTATIC kotlin/internal/UProgressionUtilKt.getProgressionLastElement
+// 0 NEW java/lang/IllegalArgumentException
+// 0 ATHROW
+// 1 INVOKESTATIC kotlin/UnsignedKt.uintCompare
+// 1 IFGT
+// 1 IF_ICMPNE
+// 2 IF
+// 0 INEG
+// 0 INVOKESTATIC kotlin/UInt.constructor-impl
+// 0 INVOKE\w+ kotlin/UInt.(un)?box-impl