[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307389 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AArch64/AArch64Subtarget.cpp b/lib/Target/AArch64/AArch64Subtarget.cpp
index df620cc2934085001bae1a849b40ecf0a756fd38..a3238cf3b60f0082e22bb023119fee5216cad9fb 100644 (file)
--- a/lib/Target/AArch64/AArch64Subtarget.cpp
+++ b/lib/Target/AArch64/AArch64Subtarget.cpp
@@ -81,6 +81,7 @@ void AArch64Subtarget::initializeProperties() {
     break;
   case CortexA57:
     MaxInterleaveFactor = 4;
+    PrefFunctionAlignment = 4;
     break;
   case ExynosM1:
     MaxInterleaveFactor = 4;

diff --git a/test/CodeGen/AArch64/preferred-function-alignment.ll b/test/CodeGen/AArch64/preferred-function-alignment.ll
index 3b3af88d34b4884267d11487cd132c6515b97fd6..88e6f5dd01c9163506d548c22712e50c0b26aa8b 100644 (file)
--- a/test/CodeGen/AArch64/preferred-function-alignment.ll
+++ b/test/CodeGen/AArch64/preferred-function-alignment.ll
@@ -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