diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -1612,6 +1612,7 @@
   PredictableSelectIsExpensive = Subtarget->getSchedModel().isOutOfOrder();
 
   setPrefLoopAlignment(Align(1ULL << Subtarget->getPrefLoopLogAlignment()));
+  setPrefFunctionAlignment(Align(1ULL << Subtarget->getPrefLoopLogAlignment()));
 
   setMinFunctionAlignment(Subtarget->isThumb() ? Align(2) : Align(4));
 
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.h b/llvm/lib/Target/ARM/ARMSubtarget.h
--- a/llvm/lib/Target/ARM/ARMSubtarget.h
+++ b/llvm/lib/Target/ARM/ARMSubtarget.h
@@ -198,7 +198,7 @@
   /// operand cycle returned by the itinerary data for pre-ISel operands.
   int PreISelOperandLatencyAdjustment = 2;
 
-  /// What alignment is preferred for loop bodies, in log2(bytes).
+  /// What alignment is preferred for loop bodies and functions, in log2(bytes).
   unsigned PrefLoopLogAlignment = 0;
 
   /// The cost factor for MVE instructions, representing the multiple beats an
diff --git a/llvm/test/CodeGen/ARM/preferred-function-alignment.ll b/llvm/test/CodeGen/ARM/preferred-function-alignment.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/preferred-function-alignment.ll
@@ -0,0 +1,23 @@
+; RUN: llc -mtriple=arm-none-eabi -mcpu=cortex-m85 < %s | FileCheck --check-prefixes=CHECK,ALIGN-16,ALIGN-CS-16 %s
+; RUN: llc -mtriple=arm-none-eabi -mcpu=cortex-m23 < %s | FileCheck --check-prefixes=CHECK,ALIGN-16,ALIGN-CS-16 %s
+
+; RUN: llc -mtriple=arm-none-eabi -mcpu=cortex-a5 < %s  | FileCheck --check-prefixes=CHECK,ALIGN-32,ALIGN-CS-32 %s
+; RUN: llc -mtriple=arm-none-eabi -mcpu=cortex-m33 < %s | FileCheck --check-prefixes=CHECK,ALIGN-32,ALIGN-CS-16 %s
+; RUN: llc -mtriple=arm-none-eabi -mcpu=cortex-m55 < %s | FileCheck --check-prefixes=CHECK,ALIGN-32,ALIGN-CS-16 %s
+
+
+; CHECK-LABEL: test
+; ALIGN-16: .p2align 1
+; ALIGN-32: .p2align 2
+
+define void @test() {
+  ret void
+}
+
+; CHECK-LABEL: test_optsize
+; ALIGN-CS-16: .p2align 1
+; ALIGN-CS-32: .p2align 2
+
+define void @test_optsize() optsize {
+  ret void
+}