[PATCH] D157514: [ARM] Set preferred function alignment

[Nicholas Guy via Phabricator via llvm-commits]

NickGuy updated this revision to Diff 550727.
NickGuy edited the summary of this revision.
NickGuy added a comment.

I've assigned the function alignment to the same as the loop alignment, as in my testing I'd seen that the values are "best" when they are equal.

> Can you improve the summary to explain why this is being done? Its the same reasons as we align loops.

Words seem to be failing me today. Hopefully the new summary makes sense.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D157514/new/

https://reviews.llvm.org/D157514

Files:
  llvm/lib/Target/ARM/ARMISelLowering.cpp
  llvm/test/CodeGen/ARM/preferred-function-alignment.ll


Index: llvm/test/CodeGen/ARM/preferred-function-alignment.ll
===================================================================
--- llvm/test/CodeGen/ARM/preferred-function-alignment.ll
+++ llvm/test/CodeGen/ARM/preferred-function-alignment.ll
@@ -1,20 +1,22 @@
-; RUN: llc -mtriple=arm-none-eabi -mcpu=generic < %s | FileCheck --check-prefixes=ALIGN-GENERIC,CHECK %s
-; RUN: llc -mtriple=arm-none-eabi -mcpu=cortex-m23 < %s | FileCheck --check-prefixes=ALIGN,CHECK %s
-; RUN: llc -mtriple=arm-none-eabi -mcpu=cortex-m33 < %s | FileCheck --check-prefixes=ALIGN,CHECK %s
-; RUN: llc -mtriple=arm-none-eabi -mcpu=cortex-m55 < %s | FileCheck --check-prefixes=ALIGN,CHECK %s
-; RUN: llc -mtriple=arm-none-eabi -mcpu=cortex-m85 < %s | FileCheck --check-prefixes=ALIGN,CHECK %s
+; 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-GENERIC: .p2align 2
-; ALIGN: .p2align 1
+; ALIGN-16: .p2align 1
+; ALIGN-32: .p2align 2
 
 define void @test() {
   ret void
 }
 
 ; CHECK-LABEL: test_optsize
-; ALIGN-GENERIC: .p2align 2
-; ALIGN: .p2align 1
+; ALIGN-CS-16: .p2align 1
+; ALIGN-CS-32: .p2align 2
 
 define void @test_optsize() optsize {
   ret void
Index: llvm/lib/Target/ARM/ARMISelLowering.cpp
===================================================================
--- llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ 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));
 


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