[PATCH] D35568: [AArch64] Use 16 bytes as preferred function alignment on Cortex-A53.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
Herald added subscribers: kristof.beyls, javed.absar, rengolin, aemerson.

This change gives a 0.23% speedup on execution time, a 0.93% improvement
in benchmark scores and a 0.55% increase in binary size on a Cortex-A53.
These numbers are the geomean results on a wide range of benchmarks from
the test-suite and a range of proprietary suites.


https://reviews.llvm.org/D35568

Files:
  lib/Target/AArch64/AArch64Subtarget.cpp
  test/CodeGen/AArch64/preferred-function-alignment.ll


Index: test/CodeGen/AArch64/preferred-function-alignment.ll
===================================================================
--- test/CodeGen/AArch64/preferred-function-alignment.ll
+++ test/CodeGen/AArch64/preferred-function-alignment.ll
@@ -1,14 +1,14 @@
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=generic < %s | FileCheck --check-prefix=ALIGN2 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=cortex-a35 < %s | FileCheck --check-prefix=ALIGN2 %s
-; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=cortex-a53 < %s | FileCheck --check-prefix=ALIGN2 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=cyclone < %s | FileCheck --check-prefix=ALIGN2 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=falkor < %s | FileCheck --check-prefix=ALIGN2 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=kryo < %s | FileCheck --check-prefix=ALIGN2 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=thunderx < %s | FileCheck --check-prefix=ALIGN3 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=thunderxt81 < %s | FileCheck --check-prefix=ALIGN3 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=thunderxt83 < %s | FileCheck --check-prefix=ALIGN3 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=thunderxt88 < %s | FileCheck --check-prefix=ALIGN3 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=thunderx2t99 < %s | FileCheck --check-prefix=ALIGN3 %s
+; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=cortex-a53 < %s | FileCheck --check-prefix=ALIGN4 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=cortex-a57 < %s | FileCheck --check-prefix=ALIGN4 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=cortex-a72 < %s | FileCheck --check-prefix=ALIGN4 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=cortex-a73 < %s | FileCheck --check-prefix=ALIGN4 %s
Index: lib/Target/AArch64/AArch64Subtarget.cpp
===================================================================
--- lib/Target/AArch64/AArch64Subtarget.cpp
+++ lib/Target/AArch64/AArch64Subtarget.cpp
@@ -130,7 +130,9 @@
     MinVectorRegisterBitWidth = 128;
     break;
   case CortexA35: break;
-  case CortexA53: break;
+  case CortexA53:
+    PrefFunctionAlignment = 4;
+    break;
   case CortexA72:
     PrefFunctionAlignment = 4;
     break;


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