aligned view factor can be a multiple of the banking factor

cucapra · May 2, 2019 · 9e43c62 · 9e43c62
1 parent 7f375d0
commit 9e43c62
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Showing 3 changed files with 29 additions and 7 deletions.
diff --git a/src/main/scala/Errors.scala b/src/main/scala/Errors.scala
@@ -79,7 +79,7 @@ object Errors {
   case class InvalidShrinkWidth(pos: Position, bf: Int, width: Int) extends TypeError(
     s"Invalid shrinking factor for view. Expected factor of $bf (banking factor), received: $width", pos)
   case class InvalidAlignFactor(pos: Position, afac: Int, bank: Int) extends TypeError(
-    s"Aligned suffix factor $afac does not divide the banking factor $bank.", pos)
+    s"Aligned suffix factor $afac is not a multiple of the banking factor $bank.", pos)
   case class ViewInsideUnroll(pos: Position, arrId: Id) extends TypeError(
     s"Cannot create view for $arrId inside an unrolled context.", pos)
   case class InvalidSplitFactor(id: Id, arrId: Id, split: Int, bank: Int, dim: Int) extends TypeError(

diff --git a/src/main/scala/TypeCheck.scala b/src/main/scala/TypeCheck.scala
@@ -258,9 +258,11 @@ object TypeChecker {
       throw InvalidShrinkWidth(view.pos, bank, shrink.get)
     }
 
+    val newBank = shrink.getOrElse(bank)
+
     val idx = suf match {
-      case Aligned(fac, idx) => if (bank < fac || bank % fac != 0) {
-        throw InvalidAlignFactor(suf.pos, fac, bank)
+      case Aligned(fac, idx) => if (newBank > fac || fac % newBank != 0) {
+        throw InvalidAlignFactor(suf.pos, fac, newBank)
       } else {
         idx
       }
@@ -273,7 +275,7 @@ object TypeChecker {
       case _:IntType => () // IntTypes are valid
     }
 
-    nEnv -> (pre.getOrElse(len) -> shrink.getOrElse(bank))
+    nEnv -> (pre.getOrElse(len) -> newBank)
   }
 
   private def checkC(cmd: Command)

diff --git a/src/test/scala/TypeCheckerSpec.scala b/src/test/scala/TypeCheckerSpec.scala
@@ -765,7 +765,7 @@ class TypeCheckerSpec extends FunSpec {
         typeCheck("""
           decl a: bit<10>[16 bank 8];
           for (let i = 0..4) {
-            view v = a[4 * i :]
+            view v = a[8 * i :]
           }
           """ )
     }
@@ -846,20 +846,40 @@ class TypeCheckerSpec extends FunSpec {
     it("width must be factor of banking factor") {
       assertThrows[InvalidAlignFactor] {
         typeCheck("""
+          decl x: bit<32>;
           decl a: bit<10>[10 bank 5];
-          view v = a[3 * i :]
+          view v = a[3 * x :]
+          """ )
+      }
+    }
+
+    it("width must be a multiple of the banking factor") {
+      assertThrows[InvalidAlignFactor] {
+        typeCheck("""
+          decl x: bit<32>;
+          decl a: bit<10>[10 bank 10];
+          view v = a[5 * x :]
           """ )
       }
     }
 
     it("width must be statically known") {
       assertThrows[ParserError] {
         typeCheck("""
+          decl x: bit<32>;
           decl a: bit<10>[10 bank 5];
-          view v = a[i * i :]
+          view v = a[x * x :]
           """ )
       }
     }
+
+    it("suffix factor is a factor of the new banking") {
+      typeCheck("""
+        decl x: bit<32>;
+        decl a: bit<10>[16 bank 8];
+        view v = a[6 * x : bank 2]
+        """ )
+    }
   }
 
   describe("Simple rotation views") {