[llvm] r307389 - [AArch64] Use 16 bytes as preferred function alignment on Cortex-A57.

[Florian Hahn via llvm-commits]

Author: fhahn
Date: Fri Jul  7 03:43:01 2017
New Revision: 307389

URL: http://llvm.org/viewvc/llvm-project?rev=307389&view=rev
Log:
[AArch64] Use 16 bytes as preferred function alignment on Cortex-A57.

Summary:
This change gives a 0.89% speed on execution time, a 0.94% improvement
in benchmark scores and a 0.62% increase in binary size on a Cortex-A57.
These numbers are the geomean results on a wide range of benchmarks from
the test-suite, SPEC2000, SPEC2006 and a range of proprietary suites.

The software optimization guide for the Cortex-A57 recommends 16 byte
branch alignment.

Reviewers: t.p.northover, mcrosier, javed.absar, kristof.beyls, sbaranga

Reviewed By: kristof.beyls

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: https://reviews.llvm.org/D34954

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64Subtarget.cpp
    llvm/trunk/test/CodeGen/AArch64/preferred-function-alignment.ll

Modified: llvm/trunk/lib/Target/AArch64/AArch64Subtarget.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64Subtarget.cpp?rev=307389&r1=307388&r2=307389&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64Subtarget.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64Subtarget.cpp Fri Jul  7 03:43:01 2017
@@ -81,6 +81,7 @@ void AArch64Subtarget::initializePropert
     break;
   case CortexA57:
     MaxInterleaveFactor = 4;
+    PrefFunctionAlignment = 4;
     break;
   case ExynosM1:
     MaxInterleaveFactor = 4;

Modified: llvm/trunk/test/CodeGen/AArch64/preferred-function-alignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/preferred-function-alignment.ll?rev=307389&r1=307388&r2=307389&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/preferred-function-alignment.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/preferred-function-alignment.ll Fri Jul  7 03:43:01 2017
@@ -1,7 +1,6 @@
 ; 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=cortex-a57 < %s | FileCheck --check-prefix=ALIGN2 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=cortex-a73 < %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
@@ -11,6 +10,7 @@
 ; 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-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=exynos-m1 < %s | FileCheck --check-prefix=ALIGN4 %s
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=exynos-m2 < %s | FileCheck --check-prefix=ALIGN4 %s