[llvm] r219734 - ARM: remove ARM/Thumb distinction for preferred alignment.

[Tim Northover]

Author: tnorthover
Date: Tue Oct 14 17:12:17 2014
New Revision: 219734

URL: http://llvm.org/viewvc/llvm-project?rev=219734&view=rev
Log:
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.

Added:
    llvm/trunk/test/CodeGen/ARM/preferred-align.ll
Removed:
    llvm/trunk/test/CodeGen/ARM/aggregate-align.ll
Modified:
    llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp
    llvm/trunk/test/CodeGen/ARM/2011-04-12-AlignBug.ll

Modified: llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp?rev=219734&r1=219733&r2=219734&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp Tue Oct 14 17:12:17 2014
@@ -102,11 +102,6 @@ static std::string computeDataLayout(ARM
   // 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";

Modified: llvm/trunk/test/CodeGen/ARM/2011-04-12-AlignBug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/2011-04-12-AlignBug.ll?rev=219734&r1=219733&r2=219734&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/2011-04-12-AlignBug.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/2011-04-12-AlignBug.ll Tue Oct 14 17:12:17 2014
@@ -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
- at .strA = private unnamed_addr constant [4 x i8] c"bar\00"
+; CHECK: align 4
+ at .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

Removed: llvm/trunk/test/CodeGen/ARM/aggregate-align.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/aggregate-align.ll?rev=219733&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/aggregate-align.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/aggregate-align.ll (removed)
@@ -1,6 +0,0 @@
-; RUN: llc -mtriple=armv7-linux-gnueabi %s -o - | FileCheck %s
-
- at var = global {i8, i8} zeroinitializer
-
-; CHECK: .globl var
-; CHECK-NEXT: .align 2

Added: llvm/trunk/test/CodeGen/ARM/preferred-align.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/preferred-align.ll?rev=219734&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/preferred-align.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/preferred-align.ll Tue Oct 14 17:12:17 2014
@@ -0,0 +1,21 @@
+; RUN: llc -mtriple=armv7-linux-gnueabi %s -o - | FileCheck %s
+
+ at var_agg = global {i8, i8} zeroinitializer
+
+; CHECK: .globl var_agg
+; CHECK-NEXT: .align 2
+
+ at var1 = global i1 zeroinitializer
+
+; CHECK: .globl var1
+; CHECK-NOT: .align
+
+ at var8 = global i8 zeroinitializer
+
+; CHECK: .globl var8
+; CHECK-NOT: .align
+
+ at var16 = global i16 zeroinitializer
+
+; CHECK: .globl var16
+; CHECK-NEXT: .align 1
\ No newline at end of file