diff --git a/include/circt/Dialect/FIRRTL/FIRRTLCanonicalization.td b/include/circt/Dialect/FIRRTL/FIRRTLCanonicalization.td
index 7a5cd3c179..0b57030226 100644
--- a/include/circt/Dialect/FIRRTL/FIRRTLCanonicalization.td
+++ b/include/circt/Dialect/FIRRTL/FIRRTLCanonicalization.td
@@ -47,6 +47,9 @@ def EqualTypes : Constraint<CPred<"areAnonymousTypesEquivalent($0.getType(), $1.
 // Constraint that enforces equal type sizes
 def EqualIntSize : Constraint<CPred<"type_cast<IntType>($0.getType()).getWidth() == type_cast<IntType>($1.getType()).getWidth()">>;
 
+// Constraint that enforces equal type signedness
+def EqualSigns : Constraint<CPred<"type_cast<IntType>($0.getType()).isSigned() == type_cast<IntType>($1.getType()).isSigned()">>;
+
 // sizeof(0) >= sizeof(1)
 def IntTypeWidthGEQ32 : Constraint<CPred<
   "type_cast<IntType>($0.getType()).getBitWidthOrSentinel() >= type_cast<IntType>($1.getType()).getBitWidthOrSentinel()">>;
@@ -684,6 +687,12 @@ def CatDoubleConst : Pat <
   (MoveNameHint $old, (CatPrimOp (CatPrimOp $cst1, (AsUIntPrimOp $cst2)), (AsUIntPrimOp $v))),
   [(KnownWidth $v), (AnyConstantOp $cst1), (AnyConstantOp $cst2)]>;
 
+// cat(asUint(x), asUint(y)) -> cat(x,y)
+def CatCast : Pat <
+  (CatPrimOp:$old (AsUIntPrimOp $x), (AsUIntPrimOp $y)),
+  (MoveNameHint $old, (CatPrimOp $x, $y)),
+  [(EqualSigns $x, $y)]>;
+
 // regreset(clock, constant_zero, resetValue) -> reg(clock)
 def RegResetWithZeroReset : Pat<
   (RegResetOp $clock, $reset, $_, $name, $nameKind, $annotations, $inner_sym, $forceable),
diff --git a/lib/Dialect/FIRRTL/FIRRTLFolds.cpp b/lib/Dialect/FIRRTL/FIRRTLFolds.cpp
index 0c23cc228c..aa93ebd0b5 100644
--- a/lib/Dialect/FIRRTL/FIRRTLFolds.cpp
+++ b/lib/Dialect/FIRRTL/FIRRTLFolds.cpp
@@ -1201,7 +1201,7 @@ void DShrPrimOp::getCanonicalizationPatterns(RewritePatternSet &results,
 
 namespace {
 // cat(bits(x, ...), bits(x, ...)) -> bits(x ...) when the two ...'s are
-// consequtive in the input.
+// consecutive in the input.
 struct CatBitsBits : public mlir::RewritePattern {
   CatBitsBits(MLIRContext *context)
       : RewritePattern(CatPrimOp::getOperationName(), 0, context) {}
@@ -1228,7 +1228,8 @@ struct CatBitsBits : public mlir::RewritePattern {
 
 void CatPrimOp::getCanonicalizationPatterns(RewritePatternSet &results,
                                             MLIRContext *context) {
-  results.insert<CatBitsBits, patterns::CatDoubleConst>(context);
+  results.insert<CatBitsBits, patterns::CatDoubleConst, patterns::CatCast>(
+      context);
 }
 
 OpFoldResult BitCastOp::fold(FoldAdaptor adaptor) {
diff --git a/test/Dialect/FIRRTL/canonicalization.mlir b/test/Dialect/FIRRTL/canonicalization.mlir
index e7b2fad560..735c4c8316 100644
--- a/test/Dialect/FIRRTL/canonicalization.mlir
+++ b/test/Dialect/FIRRTL/canonicalization.mlir
@@ -455,6 +455,7 @@ firrtl.module @Cat(in %in4: !firrtl.uint<4>,
                    out %out4: !firrtl.uint<4>,
                    out %outcst: !firrtl.uint<8>,
                    out %outcst2: !firrtl.uint<8>,
+                   out %outu8: !firrtl.uint<8>,
                    in %in0 : !firrtl.uint<0>,
                    out %outpt1: !firrtl.uint<4>,
                    out %outpt2 : !firrtl.uint<4>) {
@@ -490,6 +491,12 @@ firrtl.module @Cat(in %in4: !firrtl.uint<4>,
   %9  = firrtl.cat %c0_si2, %sin4 : (!firrtl.sint<2>, !firrtl.sint<4>) -> !firrtl.uint<6>
   %10 = firrtl.cat %c0_ui2, %9 : (!firrtl.uint<2>, !firrtl.uint<6>) -> !firrtl.uint<8>
   firrtl.connect %outcst, %10 : !firrtl.uint<8>, !firrtl.uint<8>
+
+  // CHECK: %[[fixedsign:.*]] = firrtl.cat %sin4, %sin4
+  // CHECK-NEXT: firrtl.strictconnect %outu8, %[[fixedsign]]
+  %tcast = firrtl.asUInt %sin4 : (!firrtl.sint<4>) -> !firrtl.uint<4>
+  %11 = firrtl.cat %tcast, %tcast : (!firrtl.uint<4>, !firrtl.uint<4>) -> !firrtl.uint<8>
+  firrtl.strictconnect %outu8, %11 : !firrtl.uint<8>
 }
 
 // CHECK-LABEL: firrtl.module @Bits