From 9a326368bbae7c7b52ccb9558b21022e544929e4 Mon Sep 17 00:00:00 2001
From: Bea Healy <57840981+TaoBi22@users.noreply.github.com>
Date: Wed, 30 Apr 2025 08:38:48 +0100
Subject: [PATCH] [Comb] Drop redundant concat verifier (#8454)

---
 include/circt/Dialect/Comb/Combinational.td |  1 -
 lib/Dialect/Comb/CombOps.cpp                | 12 ------------
 test/Dialect/Comb/errors.mlir               | 19 +++++++++++++++++++
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/include/circt/Dialect/Comb/Combinational.td b/include/circt/Dialect/Comb/Combinational.td
index 114d5ce1ce..9321d2912d 100644
--- a/include/circt/Dialect/Comb/Combinational.td
+++ b/include/circt/Dialect/Comb/Combinational.td
@@ -214,7 +214,6 @@ def ConcatOp : CombOp<"concat", [InferTypeOpInterface, Pure]> {
 
   let hasFolder = true;
   let hasCanonicalizeMethod = true;
-  let hasVerifier = 1;
 
   let assemblyFormat = "$inputs attr-dict `:` qualified(type($inputs))";
 
diff --git a/lib/Dialect/Comb/CombOps.cpp b/lib/Dialect/Comb/CombOps.cpp
index 652ec40fba..941a205acc 100644
--- a/lib/Dialect/Comb/CombOps.cpp
+++ b/lib/Dialect/Comb/CombOps.cpp
@@ -297,18 +297,6 @@ static unsigned getTotalWidth(ValueRange inputs) {
   return resultWidth;
 }
 
-LogicalResult ConcatOp::verify() {
-  unsigned tyWidth = cast<IntegerType>(getType()).getWidth();
-  unsigned operandsTotalWidth = getTotalWidth(getInputs());
-  if (tyWidth != operandsTotalWidth)
-    return emitOpError("ConcatOp requires operands total width to "
-                       "match type width. operands "
-                       "totalWidth is")
-           << operandsTotalWidth << ", but concatOp type width is " << tyWidth;
-
-  return success();
-}
-
 void ConcatOp::build(OpBuilder &builder, OperationState &result, Value hd,
                      ValueRange tl) {
   result.addOperands(ValueRange{hd});
diff --git a/test/Dialect/Comb/errors.mlir b/test/Dialect/Comb/errors.mlir
index d8c6ca0883..363df1b51b 100644
--- a/test/Dialect/Comb/errors.mlir
+++ b/test/Dialect/Comb/errors.mlir
@@ -11,3 +11,22 @@ hw.module @err(in %a: i1, in %b: i1) {
   // expected-error @+1 {{Truth tables support a maximum of 63 inputs}}
   %0 = comb.truth_table %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b, %a, %b -> [false]
 }
+
+// -----
+
+hw.module @err(in %a: i4, out out: i7) {
+  // expected-note @+1 {{prior use here}}
+  %0 = comb.concat %a, %a : i4, i4
+  // expected-error @+1 {{use of value '%0' expects different type than prior uses: 'i7' vs 'i8'}}
+  hw.output %0 : i7
+}
+
+// -----
+
+// Check return type is still inferred correctly with generic parser
+hw.module @err(in %a: i4, out out: i7) {
+  // expected-error @+2 {{'comb.concat' op inferred type(s) 'i8' are incompatible with return type(s) of operation 'i7'}}
+  // expected-error @+1 {{'comb.concat' op failed to infer returned types}}
+  %0 = "comb.concat"(%a, %a) : (i4, i4) -> i7
+  hw.output %0 : i7
+}