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.

llvm-svn: 219734

diff --git a/llvm/lib/Target/ARM/ARMSubtarget.cpp b/llvm/lib/Target/ARM/ARMSubtarget.cpp
index bc04f37..89534fb 100644 (file)
--- a/llvm/lib/Target/ARM/ARMSubtarget.cpp
+++ b/llvm/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/llvm/test/CodeGen/ARM/2011-04-12-AlignBug.ll b/llvm/test/CodeGen/ARM/2011-04-12-AlignBug.ll
index 97297f7..1a6879e 100644 (file)
--- a/llvm/test/CodeGen/ARM/2011-04-12-AlignBug.ll
+++ b/llvm/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/llvm/test/CodeGen/ARM/aggregate-align.ll b/llvm/test/CodeGen/ARM/aggregate-align.ll
deleted file mode 100644 (file)
index 22fc57c..0000000
--- a/llvm/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/llvm/test/CodeGen/ARM/preferred-align.ll b/llvm/test/CodeGen/ARM/preferred-align.ll
new file mode 100644 (file)
index 0000000..8cd4ef6
--- /dev/null
+++ b/llvm/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