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Diffstat (limited to 'src/main')
| -rw-r--r-- | src/main/scala/firrtl/passes/ZeroWidth.scala | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/main/scala/firrtl/passes/ZeroWidth.scala b/src/main/scala/firrtl/passes/ZeroWidth.scala index 003ab3c9..80eeab12 100644 --- a/src/main/scala/firrtl/passes/ZeroWidth.scala +++ b/src/main/scala/firrtl/passes/ZeroWidth.scala @@ -132,6 +132,10 @@ object ZeroWidth extends Transform with DependencyAPIMigration { case seq => DoPrim(Cat, seq, consts, tpe).map(onExp) } case DoPrim(Andr, Seq(x), _, _) if (bitWidth(x.tpe) == 0) => UIntLiteral(1) // nothing false + // The width of the result type of dshl is a function of the width of the shift. This has to be special cased for + // the zero-width shift case to prevent increasing the result width. Canonicalize a dshl by a zero-width element as + // just returning the unshifted expression. + case DoPrim(Dshl, Seq(x, a), _, _) if (bitWidth(a.tpe) == 0) => x case other => other.tpe match { case UIntType(IntWidth(ZERO)) => UIntLiteral(ZERO, IntWidth(BigInt(1))) |