revert new attribute and add TODO for mapping cost attr

Author: okekayode

include/circt/Dialect/Synth/SynthAttributes.td

@@ -71,19 +71,6 @@ def LinearTimingArcAttr : AttrDef<Synth_Dialect, "LinearTimingArc"> {
     "$polarity `>`";
 }
 
-def PositionalLinearTimingArcAttr : AttrDef<Synth_Dialect, "PositionalLinearTimingArc"> {
-  let mnemonic = "positional_linear_timing_arc";
-  let summary = "A simplified linear timing arc using positional input index";
-  let parameters = (ins
-    "uint64_t":$inputIndex,
-    "int64_t":$intrinsic,
-    "int64_t":$sensitivity,
-    "PolarityAttr":$polarity
-  );
-  let assemblyFormat =
-    "`<` $inputIndex `,` $intrinsic `,` $sensitivity `,` $polarity `>`";
-}
-
 def MappingCostAttr : AttrDef<Synth_Dialect, "MappingCost"> {
   let mnemonic = "mapping_cost";
   let summary = "Simplified timing and area cost for tech mapping";

lib/Dialect/Synth/SynthAttributes.cpp

@@ -25,8 +25,9 @@ MappingCostAttr::verify(llvm::function_ref<InFlightDiagnostic()> emitError,
                         DictionaryAttr inputCaps) {
   if (arcs)
     for (auto attr : arcs)
-      if (!isa<LinearTimingArcAttr, PositionalLinearTimingArcAttr>(attr))
-        return emitError() << "expected arcs to contain timing arc attributes";
+      if (!isa<LinearTimingArcAttr>(attr))
+        return emitError()
+               << "expected arcs to contain synth.linear_timing_arc";
 
   if (inputCaps)
     for (auto entry : inputCaps)

lib/Dialect/Synth/SynthOps.cpp

@@ -712,19 +712,16 @@ LogicalResult CutRewritePatternOp::verify() {
                          << blockArg.getType();
 
   auto cost = getCost();
-  if (auto arcs = cost.getArcs()) {
+  if (auto arcs = cost.getArcs())
     for (auto attr : arcs) {
-      auto arc = dyn_cast<PositionalLinearTimingArcAttr>(attr);
-      if (!arc)
+      // TODO: LinearTimingArcAttr pin names are currently ignored for cut
+      // rewrite patterns. In the future MappingCostAttr should use a 2D
+      // ArrayAttr container for arcs. Names may be dropped from
+      // LinearTimingArcAttr in a future cleanup.
+      if (!isa<LinearTimingArcAttr>(attr))
         return emitError()
-               << "mapping cost arcs for cut rewrite patterns must use "
-                  "synth.positional_linear_timing_arc";
-
-      if (arc.getInputIndex() >= functionType.getNumInputs())
-        return emitError()
-               << "mapping cost arc input index exceeds number of arguments";
+               << "mapping cost arcs must use synth.linear_timing_arc";
     }
-  }
 
   if (auto inputCaps = cost.getInputCaps())
     if (inputCaps.size() != functionType.getNumInputs())

test/Dialect/Synth/errors.mlir

@@ -43,25 +43,3 @@ synth.cut_rewrite_pattern (%a: i1) -> i1 attributes {cost = #synth.mapping_cost<
   %0 = hw.constant 0 : i2
   synth.yield %0 : i2
 }
-
-// -----
-
-// expected-error @below {{mapping cost arcs for cut rewrite patterns must use synth.positional_linear_timing_arc}}
-synth.cut_rewrite_pattern (%a: i1) -> i1 attributes {
-  cost = #synth.mapping_cost<area = 1.0 : f64, arcs = [
-    #synth.linear_timing_arc<"result", "a", 1, 0, #synth.polarity<positive>>
-  ]>
-} {
-  synth.yield %a : i1
-}
-
-// -----
-
-// expected-error @below {{mapping cost arc input index exceeds number of arguments}}
-synth.cut_rewrite_pattern (%a: i1) -> i1 attributes {
-  cost = #synth.mapping_cost<area = 1.0 : f64, arcs = [
-    #synth.positional_linear_timing_arc<1, 1, 0, #synth.polarity<positive>>
-  ]>
-} {
-  synth.yield %a : i1
-}

test/Dialect/Synth/round-trip.mlir

@@ -57,11 +57,11 @@ hw.module @gamble(in %x: i1, in %y: i1, in %z: i1) {
 
 // CHECK-LABEL: synth.cut_rewrite_pattern
 // CHECK-SAME: (%{{.*}}: i1, %{{.*}}: i1, %{{.*}}: i1) -> i1
-// CHECK-SAME: attributes {cost = #synth.mapping_cost<area =
-// CHECK-SAME: #synth.positional_linear_timing_arc<1, 1, 0, <positive>>
+// CHECK-SAME: attributes {cost = #synth.mapping_cost<area = 
+// CHECK-SAME: #synth.linear_timing_arc<"result", "b", 1, 0, <positive>>
 synth.cut_rewrite_pattern (%a: i1, %b: i1, %c: i1) -> i1 attributes {
   cost = #synth.mapping_cost<area = 1.0 : f64, arcs = [
-    #synth.positional_linear_timing_arc<1, 1, 0, #synth.polarity<positive>>
+    #synth.linear_timing_arc<"result", "b", 1, 0, #synth.polarity<positive>>
   ]>
 } {
   %0 = synth.aig.and_inv %a, not %b, %c : i1