diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index 56ae5c010411..bc0f1e9f400c 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -209,10 +209,7 @@ namespace {
                                        ? CurrentDynamicCostSavingsDiscount
                                        : UP.DynamicCostSavingsDiscount;
 
-      if (!UserThreshold &&
-          // FIXME: Use Function::optForSize().
-          L->getHeader()->getParent()->hasFnAttribute(
-              Attribute::OptimizeForSize)) {
+      if (!UserThreshold && L->getHeader()->getParent()->optForSize()) {
         Threshold = UP.OptSizeThreshold;
         PartialThreshold = UP.PartialOptSizeThreshold;
       }
diff --git a/llvm/test/Transforms/LoopUnroll/partial-unroll-optsize.ll b/llvm/test/Transforms/LoopUnroll/partial-unroll-optsize.ll
index a650317f3df7..e5e0151761bf 100644
--- a/llvm/test/Transforms/LoopUnroll/partial-unroll-optsize.ll
+++ b/llvm/test/Transforms/LoopUnroll/partial-unroll-optsize.ll
@@ -1,4 +1,6 @@
 ; RUN: opt < %s -S -loop-unroll -unroll-allow-partial | FileCheck %s
+; RUN: sed -e 's/optsize/minsize/' %s | opt -S -loop-unroll -unroll-allow-partial | FileCheck %s
+
 ; Loop size = 3, when the function has the optsize attribute, the
 ; OptSizeUnrollThreshold, i.e. 50, is used, hence the loop should be unrolled
 ; by 32 times because (1 * 32) + 2 < 50 (whereas (1 * 64 + 2) is not).
@@ -49,4 +51,3 @@ exit:
 ; CHECK-NEXT: add
 ; CHECK-NEXT: add
 ; CHECK-NEXT: icmp
-