From: James Molloy <james.molloy@arm.com>
Date: Wed, 22 Apr 2015 09:11:38 +0000 (+0000)
Subject: [AArch64] Disable complex GEP optimization by default.
X-Git-Tag: android-x86-7.1-r4~48974
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=89cc8dd3b84a636b2798028a994f4b71c78e0163;p=android-x86%2Fexternal-llvm.git

[AArch64] Disable complex GEP optimization by default.

Enough concerns were raised that this optimization is pessimising some code patterns.

The obvious fix, to add a Reassociate run afterwards, causes even more pessimisation in some cases due to fewer complex addressing modes being matched. As there isn't a trivial fix for this, backing this out by default until someone gets a chance to fix the addressing mode matcher.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235491 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/AArch64/AArch64TargetMachine.cpp b/lib/Target/AArch64/AArch64TargetMachine.cpp
index ab28a16515d..a9059ab37f5 100644
--- a/lib/Target/AArch64/AArch64TargetMachine.cpp
+++ b/lib/Target/AArch64/AArch64TargetMachine.cpp
@@ -85,7 +85,7 @@ EnableA53Fix835769("aarch64-fix-cortex-a53-835769", cl::Hidden,
 static cl::opt<bool>
 EnableGEPOpt("aarch64-gep-opt", cl::Hidden,
              cl::desc("Enable optimizations on complex GEPs"),
-             cl::init(true));
+             cl::init(false));
 
 // FIXME: Unify control over GlobalMerge.
 static cl::opt<cl::boolOrDefault>
diff --git a/test/CodeGen/AArch64/aarch64-gep-opt.ll b/test/CodeGen/AArch64/aarch64-gep-opt.ll
index ce6c8a06c64..93e2ff14ac7 100644
--- a/test/CodeGen/AArch64/aarch64-gep-opt.ll
+++ b/test/CodeGen/AArch64/aarch64-gep-opt.ll
@@ -1,6 +1,6 @@
-; RUN: llc -O3 -verify-machineinstrs %s -o - | FileCheck %s
-; RUN: llc -O3 -print-after=codegenprepare -mcpu=cyclone < %s >%t 2>&1 && FileCheck --check-prefix=CHECK-NoAA <%t %s
-; RUN: llc -O3 -print-after=codegenprepare -mcpu=cortex-a53 < %s >%t 2>&1 && FileCheck --check-prefix=CHECK-UseAA <%t %s
+; RUN: llc -O3 -aarch64-gep-opt=true -verify-machineinstrs %s -o - | FileCheck %s
+; RUN: llc -O3 -aarch64-gep-opt=true -print-after=codegenprepare -mcpu=cyclone < %s >%t 2>&1 && FileCheck --check-prefix=CHECK-NoAA <%t %s
+; RUN: llc -O3 -aarch64-gep-opt=true -print-after=codegenprepare -mcpu=cortex-a53 < %s >%t 2>&1 && FileCheck --check-prefix=CHECK-UseAA <%t %s
 target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
 target triple = "aarch64-linux-gnueabi"