[llvm] r307380 - [AArch64] Use 16 bytes as preferred function alignment on Cortex-A72.

[Florian Hahn via llvm-commits]

Author: fhahn
Date: Fri Jul  7 03:15:49 2017
New Revision: 307380

URL: http://llvm.org/viewvc/llvm-project?rev=307380&view=rev
Log:
[AArch64] Use 16 bytes as preferred function alignment on Cortex-A72.

Summary:
This change gives a 0.34% speed on execution time, a 0.61% improvement
in benchmark scores and a 0.57% increase in binary size on a Cortex-A72.
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-A72 recommends 16 byte
branch alignment.


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

Reviewed By: kristof.beyls

Subscribers: llvm-commits, aemerson

Differential Revision: https://reviews.llvm.org/D34961

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=307380&r1=307379&r2=307380&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64Subtarget.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64Subtarget.cpp Fri Jul  7 03:15:49 2017
@@ -130,7 +130,9 @@ void AArch64Subtarget::initializePropert
     break;
   case CortexA35: break;
   case CortexA53: break;
-  case CortexA72: break;
+  case CortexA72:
+    PrefFunctionAlignment = 4;
+    break;
   case CortexA73: break;
   case Others: break;
   }

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=307380&r1=307379&r2=307380&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/preferred-function-alignment.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/preferred-function-alignment.ll Fri Jul  7 03:15:49 2017
@@ -2,7 +2,6 @@
 ; 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-a72 < %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
@@ -12,6 +11,7 @@
 ; 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-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
 ; RUN: llc -mtriple=aarch64-unknown-linux -mcpu=exynos-m3 < %s | FileCheck --check-prefix=ALIGN4 %s