diff --git a/mlir/lib/Dialect/StandardOps/IR/Ops.cpp b/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
--- a/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
+++ b/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
@@ -2183,7 +2183,9 @@
 
 OpFoldResult TruncateIOp::fold(ArrayRef<Attribute> operands) {
   // trunci(zexti(a)) -> a
-  if (matchPattern(getOperand(), m_Op<ZeroExtendIOp>()))
+  // trunci(sexti(a)) -> a
+  if (matchPattern(getOperand(), m_Op<ZeroExtendIOp>()) ||
+      matchPattern(getOperand(), m_Op<SignExtendIOp>()))
     return getOperand().getDefiningOp()->getOperand(0);
 
   return nullptr;
diff --git a/mlir/test/Transforms/canonicalize.mlir b/mlir/test/Transforms/canonicalize.mlir
--- a/mlir/test/Transforms/canonicalize.mlir
+++ b/mlir/test/Transforms/canonicalize.mlir
@@ -1109,3 +1109,14 @@
   %1 = trunci %0 : vector<4xi8> to vector<4xi2>
   return %1 : vector<4xi2>
 }
+
+// -----
+
+// CHECK-LABEL: func @fold_trunci_sexti
+// CHECK-SAME:    (%[[ARG0:[0-9a-z]*]]: i1)
+func @fold_trunci_sexti(%arg0: i1) -> i1 attributes {} {
+  // CHECK-NEXT: return %[[ARG0]] : i1
+  %0 = sexti %arg0 : i1 to i8
+  %1 = trunci %0 : i8 to i1
+  return %1 : i1
+}