From: Tim Northover <tnorthover@apple.com>
Date: Tue, 14 Oct 2014 22:12:17 +0000 (+0000)
Subject: ARM: remove ARM/Thumb distinction for preferred alignment.
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=7419c9c0c0167eff3aa3a5263e566c0f702dffb2

ARM: remove ARM/Thumb distinction for preferred alignment.

Thumb1 has legitimate reasons for preferring 32-bit alignment of types
i1/i8/i16, since the 16-bit encoding of "add rD, sp, #imm" requires #imm to be
a multiple of 4. However, this is a trade-off betweem code size and RAM usage;
the DataLayout string is not the best place to represent it even if desired.

So this patch removes the extra Thumb requirements, hopefully making ARM and
Thumb completely compatible in this respect.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219734 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/ARM/ARMSubtarget.cpp b/lib/Target/ARM/ARMSubtarget.cpp
index bc04f37331e..89534fb0141 100644
--- a/lib/Target/ARM/ARMSubtarget.cpp
+++ b/lib/Target/ARM/ARMSubtarget.cpp
@@ -102,11 +102,6 @@ static std::string computeDataLayout(ARMSubtarget &ST) {
   // Pointers are 32 bits and aligned to 32 bits.
   Ret += "-p:32:32";
 
-  // On thumb, i16,i18 and i1 have natural aligment requirements, but we try to
-  // align to 32.
-  if (ST.isThumb())
-    Ret += "-i1:8:32-i8:8:32-i16:16:32";
-
   // ABIs other than APCS have 64 bit integers with natural alignment.
   if (!ST.isAPCS_ABI())
     Ret += "-i64:64";
diff --git a/test/CodeGen/ARM/2011-04-12-AlignBug.ll b/test/CodeGen/ARM/2011-04-12-AlignBug.ll
index 97297f78c7e..1a6879e366e 100644
--- a/test/CodeGen/ARM/2011-04-12-AlignBug.ll
+++ b/test/CodeGen/ARM/2011-04-12-AlignBug.ll
@@ -1,11 +1,10 @@
 ; RUN: llc < %s | FileCheck %s
-target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:32-f32:32:32-f64:32:32-v64:32:64-v128:32:128-a0:0:32-n32"
 target triple = "thumbv7-apple-darwin10.0.0"
 
 ; CHECK: align 3
 @.v = private unnamed_addr constant <4 x i32> <i32 1, i32 2, i32 3, i32 4>, align 8
-; CHECK: align 2
-@.strA = private unnamed_addr constant [4 x i8] c"bar\00"
+; CHECK: align 4
+@.strA = private unnamed_addr constant [4 x i64] zeroinitializer
 ; CHECK-NOT: align
 @.strB = private unnamed_addr constant [4 x i8] c"foo\00", align 1
 @.strC = private unnamed_addr constant [4 x i8] c"baz\00", section "__TEXT,__cstring,cstring_literals", align 1
diff --git a/test/CodeGen/ARM/aggregate-align.ll b/test/CodeGen/ARM/aggregate-align.ll
deleted file mode 100644
index 22fc57c1de7..00000000000
--- a/test/CodeGen/ARM/aggregate-align.ll
+++ /dev/null
@@ -1,6 +0,0 @@
-; RUN: llc -mtriple=armv7-linux-gnueabi %s -o - | FileCheck %s
-
-@var = global {i8, i8} zeroinitializer
-
-; CHECK: .globl var
-; CHECK-NEXT: .align 2
diff --git a/test/CodeGen/ARM/preferred-align.ll b/test/CodeGen/ARM/preferred-align.ll
new file mode 100644
index 00000000000..8cd4ef61546
--- /dev/null
+++ b/test/CodeGen/ARM/preferred-align.ll
@@ -0,0 +1,21 @@
+; RUN: llc -mtriple=armv7-linux-gnueabi %s -o - | FileCheck %s
+
+@var_agg = global {i8, i8} zeroinitializer
+
+; CHECK: .globl var_agg
+; CHECK-NEXT: .align 2
+
+@var1 = global i1 zeroinitializer
+
+; CHECK: .globl var1
+; CHECK-NOT: .align
+
+@var8 = global i8 zeroinitializer
+
+; CHECK: .globl var8
+; CHECK-NOT: .align
+
+@var16 = global i16 zeroinitializer
+
+; CHECK: .globl var16
+; CHECK-NEXT: .align 1
\ No newline at end of file