Index: mlir/lib/Dialect/SCF/SCF.cpp
===================================================================
--- mlir/lib/Dialect/SCF/SCF.cpp
+++ mlir/lib/Dialect/SCF/SCF.cpp
@@ -685,8 +685,9 @@
   }
 };
 
-/// Rewriting pattern that erases loops that are known not to iterate and
-/// replaces single-iteration loops with their bodies.
+/// Rewriting pattern that erases loops that are known not to iterate, replaces
+/// single-iteration loops with their bodies, and removes empty loops that
+/// iterate at least once and only return values defined outside of the loop.
 struct SimplifyTrivialLoops : public OpRewritePattern<ForOp> {
   using OpRewritePattern<ForOp>::OpRewritePattern;
 
@@ -728,7 +729,18 @@
       return success();
     }
 
-    return failure();
+    Block &block = op.getRegion().front();
+    if (!llvm::hasSingleElement(block))
+      return failure();
+    // If the loop is empty, iterates at least once, and only returns values
+    // defined outside of the loop, remove it.
+    auto yieldOp = cast<scf::YieldOp>(block.getTerminator());
+    auto yieldOperands = yieldOp.getOperands();
+    for (auto operand : yieldOperands)
+      if (!op.isDefinedOutsideOfLoop(operand))
+        return failure();
+    rewriter.replaceOp(op, yieldOperands);
+    return success();
   }
 };
 
Index: mlir/test/Dialect/SCF/canonicalize.mlir
===================================================================
--- mlir/test/Dialect/SCF/canonicalize.mlir
+++ mlir/test/Dialect/SCF/canonicalize.mlir
@@ -361,6 +361,22 @@
 //  CHECK-NEXT:     }
 //  CHECK-NEXT:     return %[[a]], %[[r1]], %[[b]] : i32, i32, i32
 
+func @for_yields_4() -> i32 {
+  %c0 = arith.constant 0 : index
+  %c1 = arith.constant 1 : index
+  %c2 = arith.constant 2 : index
+  %a = arith.constant 3 : i32
+  %b = call @make_i32() : () -> (i32)
+  %r = scf.for %i = %c0 to %c2 step %c1 iter_args(%0 = %a) -> i32 {
+    scf.yield %b : i32
+  }
+  return %r : i32
+}
+
+// CHECK-LABEL:   func @for_yields_4
+//  CHECK-NEXT:     %[[b:.*]] = call @make_i32() : () -> i32
+//  CHECK-NEXT:     return %[[b]] : i32
+
 // -----
 
 // CHECK-LABEL: @replace_true_if