vioProbe uses its clock lazily (#2551)

Fixes #2532
clash-lang · Aug 18, 2023 · a02d6a3 · a02d6a3
1 parent 3a2d320
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diff --git a/clash-cores/clash-cores.cabal b/clash-cores/clash-cores.cabal
@@ -153,6 +153,7 @@ library
   build-depends:
     clash-lib,
     infinite-list           ^>= 0.1,
+    ghc-prim                >= 0.3.1.0 && < 1.0,
     mtl                     >= 2.1.1 && < 2.4,
     pretty-show,
     prettyprinter           >= 1.2.0.1  && < 1.8,

diff --git a/clash-cores/src/Clash/Cores/Xilinx/VIO.hs b/clash-cores/src/Clash/Cores/Xilinx/VIO.hs
@@ -49,6 +49,7 @@ import Clash.Explicit.Prelude
 import Clash.Annotations.Primitive (Primitive (InlineYamlPrimitive))
 
 import Data.String.Interpolate (__i)
+import GHC.Magic (lazy)
 
 import Clash.Cores.Xilinx.VIO.Internal.BlackBoxes
 
@@ -123,7 +124,12 @@ vioProbe# ::
   o ->
   Clock dom ->
   a
-vioProbe# !_inputNames !_outputNames !_initialOutputProbeValues !_clk = vioX @dom @a @o
+vioProbe# !_inputNames !_outputNames !_initialOutputProbeValues clk =
+  lazy clk `seq` -- Ensure clk is considered used, but not marked "used once".
+                 -- This makes makes GHC not inline the clock argument.
+                 --
+                 -- Fixes #2532
+  vioX @dom @a @o
 -- See: https://github.com/clash-lang/clash-compiler/pull/2511
 {-# CLASH_OPAQUE vioProbe# #-}
 {-# ANN vioProbe# (