From e1e7e0feaf1f444d90c771d5ae16ad4a66e9ed88 Mon Sep 17 00:00:00 2001
From: Chris Lattner <clattner@nondot.org>
Date: Sun, 19 Sep 2021 12:33:01 -0700
Subject: [PATCH] [SV] Switch LocalParamOp to take an attribute instead of SSA
 value.

This keeps params and attributes in different domains.  This will
allow better enforcement of valid parameter values in the verifier.
---
 include/circt/Dialect/SV/SVExpressions.td       | 11 ++++-------
 lib/Translation/ExportVerilog/ExportVerilog.cpp |  2 +-
 test/Dialect/SV/basic.mlir                      |  6 +++---
 test/ExportVerilog/sv-dialect.mlir              |  9 ++++-----
 4 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/include/circt/Dialect/SV/SVExpressions.td b/include/circt/Dialect/SV/SVExpressions.td
index 385635228d..4fa4777614 100644
--- a/include/circt/Dialect/SV/SVExpressions.td
+++ b/include/circt/Dialect/SV/SVExpressions.td
@@ -95,20 +95,17 @@ def ConstantZOp : SVOp<"constantZ", [NoSideEffect, HasCustomSSAName]> {
 }
 
 def LocalParamOp : SVOp<"localparam",
-      [SameOperandsAndResultType, NoSideEffect, HasCustomSSAName]> {
+      [FirstAttrDerivedResultType, NoSideEffect, HasCustomSSAName]> {
   let summary = "Declare a localparam";
   let description = [{
     The localparam operation produces a `localparam` declaration. See SV spec
     6.20.4 p125.
-    ```
-      %result = hw.localparam %input : t1
-    ```
     }];
 
-  let arguments = (ins StrAttr:$name, HWIntegerType:$input);
-  let results = (outs HWIntegerType:$result);
+  let arguments = (ins AnyAttr:$value, StrAttr:$name);
+  let results = (outs HWValueType:$result);
 
   let assemblyFormat = [{
-    custom<ImplicitSSAName>(attr-dict) $input `:` type($result)
+    `:` type($result) custom<ImplicitSSAName>(attr-dict)
   }];
 }
diff --git a/lib/Translation/ExportVerilog/ExportVerilog.cpp b/lib/Translation/ExportVerilog/ExportVerilog.cpp
index 7368850a19..6b7d87a7ca 100644
--- a/lib/Translation/ExportVerilog/ExportVerilog.cpp
+++ b/lib/Translation/ExportVerilog/ExportVerilog.cpp
@@ -2860,7 +2860,7 @@ void StmtEmitter::collectNamesEmitDecls(Block &block) {
 
     if (auto localparam = dyn_cast<LocalParamOp>(op)) {
       os << " = ";
-      emitExpression(localparam.input(), opsForLocation, ForceEmitMultiUse);
+      printParamValue(localparam.value(), op, localparam.name(), os);
     }
 
     // Constants carry their assignment directly in the declaration.
diff --git a/test/Dialect/SV/basic.mlir b/test/Dialect/SV/basic.mlir
index a04c138db1..565aaaf3ed 100644
--- a/test/Dialect/SV/basic.mlir
+++ b/test/Dialect/SV/basic.mlir
@@ -4,9 +4,9 @@
 // CHECK-LABEL: hw.module @test1(%arg0: i1, %arg1: i1, %arg8: i8) {
 hw.module @test1(%arg0: i1, %arg1: i1, %arg8: i8) {
 
-  %c11_i42 = hw.constant 11: i42
-  // CHECK: %param_x = sv.localparam %c11_i42 : i42
-  %param_x = sv.localparam %c11_i42 : i42
+  // CHECK: %param_x = sv.localparam : i42 {value = 11 : i42}
+  %param_x = sv.localparam : i42 {value = 11 : i42}
+
 
   // This corresponds to this block of system verilog code:
   //    always @(posedge arg0) begin
diff --git a/test/ExportVerilog/sv-dialect.mlir b/test/ExportVerilog/sv-dialect.mlir
index ad207f8e1e..d0c437bfb9 100644
--- a/test/ExportVerilog/sv-dialect.mlir
+++ b/test/ExportVerilog/sv-dialect.mlir
@@ -6,12 +6,11 @@ hw.module @M1(%clock : i1, %cond : i1, %val : i8) {
   %forceWire = sv.wire : !hw.inout<i1>
  
   %c11_i42 = hw.constant 11: i42
-  // CHECK: localparam [41:0] param_x = 42'hB;
-  %param_x = sv.localparam %c11_i42 : i42
+  // CHECK: localparam [41:0] param_x = 42'd11;
+  %param_x = sv.localparam : i42 { value = 11: i42 }
 
-  %param_tmp = comb.add %param_x, %c11_i42 : i42
-  // CHECK: localparam [41:0] param_y = param_x + 42'hB;
-  %param_y = sv.localparam %param_tmp : i42
+  // CHECK: localparam [41:0] param_y = 42'd4;
+  %param_y = sv.localparam : i42 { value = 4: i42 }
 
   // CHECK:      always @(posedge clock) begin
   sv.always posedge %clock {