[llvm] r233024 - [AArch64, ARM] Enable GlobalMerge with -O3 rather than -O1.

Ahmed Bougacha ahmed.bougacha at gmail.com
Mon Mar 23 14:17:37 PDT 2015 

Author: ab
Date: Mon Mar 23 16:17:36 2015
New Revision: 233024

URL: http://llvm.org/viewvc/llvm-project?rev=233024&view=rev
Log:
[AArch64, ARM] Enable GlobalMerge with -O3 rather than -O1.

The pass used to be enabled by default with CodeGenOpt::Less (-O1).
This is too aggressive, considering the pass indiscriminately merges
all globals together.

Currently, performance doesn't always improve, and, on code that uses
few globals (e.g., the odd file- or function- static), more often than
not is degraded by the optimization.  Lengthy discussion can be found
on llvmdev (AArch64-focused;  ARM has similar problems):
  http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-February/082800.html
Also, it makes tooling and debuggers less useful when dealing with
globals and data sections.

GlobalMerge needs to better identify those cases that benefit, and this
will be done separately.  In the meantime, move the pass to run with
-O3 rather than -O1, on both ARM and AArch64.

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64TargetMachine.cpp
    llvm/trunk/lib/Target/ARM/ARMTargetMachine.cpp
    llvm/trunk/test/CodeGen/AArch64/global-merge-1.ll
    llvm/trunk/test/CodeGen/AArch64/global-merge-2.ll
    llvm/trunk/test/CodeGen/AArch64/global-merge-3.ll
    llvm/trunk/test/CodeGen/AArch64/global-merge-4.ll
    llvm/trunk/test/CodeGen/ARM/2010-12-15-elf-lcomm.ll
    llvm/trunk/test/CodeGen/ARM/2011-01-19-MergedGlobalDbg.ll
    llvm/trunk/test/CodeGen/ARM/2011-06-29-MergeGlobalsAlign.ll
    llvm/trunk/test/CodeGen/ARM/2011-08-02-MergedGlobalDbg.ll
    llvm/trunk/test/CodeGen/ARM/global-merge-1.ll
    llvm/trunk/test/CodeGen/ARM/global-merge-addrspace.ll
    llvm/trunk/test/CodeGen/ARM/global-merge.ll

Modified: llvm/trunk/lib/Target/AArch64/AArch64TargetMachine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64TargetMachine.cpp?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64TargetMachine.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64TargetMachine.cpp Mon Mar 23 16:17:36 2015
@@ -245,7 +245,7 @@ bool AArch64PassConfig::addPreISel() {
   // FIXME: On AArch64, this depends on the type.
   // Basically, the addressable offsets are up to 4095 * Ty.getSizeInBytes().
   // and the offset has to be a multiple of the related size in bytes.
-  if (TM->getOptLevel() != CodeGenOpt::None)
+  if (TM->getOptLevel() == CodeGenOpt::Aggressive)
     addPass(createGlobalMergePass(TM, 4095));
   if (TM->getOptLevel() != CodeGenOpt::None)
     addPass(createAArch64AddressTypePromotionPass());

Modified: llvm/trunk/lib/Target/ARM/ARMTargetMachine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMTargetMachine.cpp?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMTargetMachine.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMTargetMachine.cpp Mon Mar 23 16:17:36 2015
@@ -327,7 +327,7 @@ void ARMPassConfig::addIRPasses() {
 }
 
 bool ARMPassConfig::addPreISel() {
-  if (TM->getOptLevel() != CodeGenOpt::None)
+  if (TM->getOptLevel() == CodeGenOpt::Aggressive)
     // FIXME: This is using the thumb1 only constant value for
     // maximal global offset for merging globals. We may want
     // to look into using the old value for non-thumb1 code of

Modified: llvm/trunk/test/CodeGen/AArch64/global-merge-1.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/global-merge-1.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/global-merge-1.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/global-merge-1.ll Mon Mar 23 16:17:36 2015
@@ -1,11 +1,11 @@
-; RUN: llc %s -mtriple=aarch64-none-linux-gnu -enable-global-merge -o - | FileCheck %s
-; RUN: llc %s -mtriple=aarch64-none-linux-gnu -enable-global-merge -global-merge-on-external -o - | FileCheck %s
+; RUN: llc %s -mtriple=aarch64-none-linux-gnu -O3 -enable-global-merge -o - | FileCheck %s
+; RUN: llc %s -mtriple=aarch64-none-linux-gnu -O3 -enable-global-merge -global-merge-on-external -o - | FileCheck %s
 
-; RUN: llc %s -mtriple=aarch64-linux-gnuabi -enable-global-merge -o - | FileCheck %s
-; RUN: llc %s -mtriple=aarch64-linux-gnuabi -enable-global-merge -global-merge-on-external -o - | FileCheck %s
+; RUN: llc %s -mtriple=aarch64-linux-gnuabi -O3 -enable-global-merge -o - | FileCheck %s
+; RUN: llc %s -mtriple=aarch64-linux-gnuabi -O3 -enable-global-merge -global-merge-on-external -o - | FileCheck %s
 
-; RUN: llc %s -mtriple=aarch64-apple-ios -enable-global-merge -o - | FileCheck %s --check-prefix=CHECK-APPLE-IOS
-; RUN: llc %s -mtriple=aarch64-apple-ios -enable-global-merge -global-merge-on-external -o - | FileCheck %s --check-prefix=CHECK-APPLE-IOS
+; RUN: llc %s -mtriple=aarch64-apple-ios -O3 -enable-global-merge -o - | FileCheck %s --check-prefix=CHECK-APPLE-IOS
+; RUN: llc %s -mtriple=aarch64-apple-ios -O3 -enable-global-merge -global-merge-on-external -o - | FileCheck %s --check-prefix=CHECK-APPLE-IOS
 
 @m = internal global i32 0, align 4
 @n = internal global i32 0, align 4

Modified: llvm/trunk/test/CodeGen/AArch64/global-merge-2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/global-merge-2.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/global-merge-2.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/global-merge-2.ll Mon Mar 23 16:17:36 2015
@@ -1,6 +1,6 @@
-; RUN: llc %s -mtriple=aarch64-none-linux-gnu -enable-global-merge -global-merge-on-external -o - | FileCheck %s
-; RUN: llc %s -mtriple=aarch64-linux-gnuabi -enable-global-merge -global-merge-on-external -o - | FileCheck %s
-; RUN: llc %s -mtriple=aarch64-apple-ios -enable-global-merge -global-merge-on-external -o - | FileCheck %s --check-prefix=CHECK-APPLE-IOS
+; RUN: llc %s -mtriple=aarch64-none-linux-gnu -O3 -enable-global-merge -global-merge-on-external -o - | FileCheck %s
+; RUN: llc %s -mtriple=aarch64-linux-gnuabi -O3 -enable-global-merge -global-merge-on-external -o - | FileCheck %s
+; RUN: llc %s -mtriple=aarch64-apple-ios -O3 -enable-global-merge -global-merge-on-external -o - | FileCheck %s --check-prefix=CHECK-APPLE-IOS
 
 @x = global i32 0, align 4
 @y = global i32 0, align 4

Modified: llvm/trunk/test/CodeGen/AArch64/global-merge-3.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/global-merge-3.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/global-merge-3.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/global-merge-3.ll Mon Mar 23 16:17:36 2015
@@ -1,6 +1,6 @@
-; RUN: llc %s -mtriple=aarch64-none-linux-gnu -enable-global-merge -global-merge-on-external -o - | FileCheck %s
-; RUN: llc %s -mtriple=aarch64-linux-gnuabi -enable-global-merge -global-merge-on-external -o - | FileCheck %s
-; RUN: llc %s -mtriple=aarch64-apple-ios -enable-global-merge -global-merge-on-external -o - | FileCheck %s --check-prefix=CHECK-APPLE-IOS
+; RUN: llc %s -mtriple=aarch64-none-linux-gnu -O3 -enable-global-merge -global-merge-on-external -o - | FileCheck %s
+; RUN: llc %s -mtriple=aarch64-linux-gnuabi -O3 -enable-global-merge -global-merge-on-external -o - | FileCheck %s
+; RUN: llc %s -mtriple=aarch64-apple-ios -O3 -enable-global-merge -global-merge-on-external -o - | FileCheck %s --check-prefix=CHECK-APPLE-IOS
 
 @x = global [1000 x i32] zeroinitializer, align 1
 @y = global [1000 x i32] zeroinitializer, align 1

Modified: llvm/trunk/test/CodeGen/AArch64/global-merge-4.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/global-merge-4.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/global-merge-4.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/global-merge-4.ll Mon Mar 23 16:17:36 2015
@@ -1,4 +1,4 @@
-; RUN: llc %s -mtriple=aarch64-linux-gnuabi -enable-global-merge -o - | FileCheck %s
+; RUN: llc %s -mtriple=aarch64-linux-gnuabi -O3 -enable-global-merge -o - | FileCheck %s
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-n32:64-S128"
 target triple = "arm64-apple-ios7.0.0"

Modified: llvm/trunk/test/CodeGen/ARM/2010-12-15-elf-lcomm.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/2010-12-15-elf-lcomm.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/2010-12-15-elf-lcomm.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/2010-12-15-elf-lcomm.ll Mon Mar 23 16:17:36 2015
@@ -1,6 +1,6 @@
-; RUN: llc  %s -mtriple=armv7-linux-gnueabi -filetype=obj -o - | \
+; RUN: llc  %s -mtriple=armv7-linux-gnueabi -O3 -filetype=obj -o - | \
 ; RUN:    llvm-readobj -s -t | FileCheck  -check-prefix=OBJ %s
-; RUN: llc  %s -mtriple=armv7-linux-gnueabi -o - | \
+; RUN: llc  %s -mtriple=armv7-linux-gnueabi -O3 -o - | \
 ; RUN:    FileCheck  -check-prefix=ASM %s
 
 

Modified: llvm/trunk/test/CodeGen/ARM/2011-01-19-MergedGlobalDbg.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/2011-01-19-MergedGlobalDbg.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/2011-01-19-MergedGlobalDbg.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/2011-01-19-MergedGlobalDbg.ll Mon Mar 23 16:17:36 2015
@@ -1,4 +1,4 @@
-; RUN: llc -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+; RUN: llc -O3 -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
 
 target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n32"
 target triple = "thumbv7-apple-darwin10"

Modified: llvm/trunk/test/CodeGen/ARM/2011-06-29-MergeGlobalsAlign.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/2011-06-29-MergeGlobalsAlign.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/2011-06-29-MergeGlobalsAlign.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/2011-06-29-MergeGlobalsAlign.ll Mon Mar 23 16:17:36 2015
@@ -1,4 +1,4 @@
-; RUN: llc < %s -mtriple=thumbv7-apple-darwin10 | FileCheck %s
+; RUN: llc < %s -mtriple=thumbv7-apple-darwin10 -O3 | FileCheck %s
 ; CHECK: .zerofill __DATA,__bss,__MergedGlobals,16,2
 
 @prev = external global [0 x i16]

Modified: llvm/trunk/test/CodeGen/ARM/2011-08-02-MergedGlobalDbg.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/2011-08-02-MergedGlobalDbg.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/2011-08-02-MergedGlobalDbg.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/2011-08-02-MergedGlobalDbg.ll Mon Mar 23 16:17:36 2015
@@ -1,4 +1,4 @@
-; RUN: llc -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+; RUN: llc -O3 -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
 
 ; Check debug info output for merged global.
 ; DW_AT_location

Modified: llvm/trunk/test/CodeGen/ARM/global-merge-1.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/global-merge-1.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/global-merge-1.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/global-merge-1.ll Mon Mar 23 16:17:36 2015
@@ -1,9 +1,10 @@
 ; RUN: llc %s -O0 -o - | FileCheck -check-prefix=NO-MERGE %s
-; RUN: llc %s -O0 -o - -enable-global-merge=false | FileCheck -check-prefix=NO-MERGE %s
-; RUN: llc %s -O0 -o - -enable-global-merge=true | FileCheck -check-prefix=NO-MERGE %s
-; RUN: llc %s -O1 -o - | FileCheck -check-prefix=MERGE %s
+; RUN: llc %s -O1 -o - | FileCheck -check-prefix=NO-MERGE %s
 ; RUN: llc %s -O1 -o - -enable-global-merge=false | FileCheck -check-prefix=NO-MERGE %s
-; RUN: llc %s -O1 -o - -enable-global-merge=true | FileCheck -check-prefix=MERGE %s
+; RUN: llc %s -O1 -o - -enable-global-merge=true | FileCheck -check-prefix=NO-MERGE %s
+; RUN: llc %s -O3 -o - | FileCheck -check-prefix=MERGE %s
+; RUN: llc %s -O3 -o - -enable-global-merge=false | FileCheck -check-prefix=NO-MERGE %s
+; RUN: llc %s -O3 -o - -enable-global-merge=true | FileCheck -check-prefix=MERGE %s
 
 ; MERGE-NOT: .zerofill __DATA,__bss,_bar,20,2
 ; MERGE-NOT: .zerofill __DATA,__bss,_baz,20,2

Modified: llvm/trunk/test/CodeGen/ARM/global-merge-addrspace.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/global-merge-addrspace.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/global-merge-addrspace.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/global-merge-addrspace.ll Mon Mar 23 16:17:36 2015
@@ -1,4 +1,4 @@
-; RUN: llc < %s -mtriple=thumb-apple-darwin | FileCheck %s
+; RUN: llc < %s -mtriple=thumb-apple-darwin -O3 | FileCheck %s
 ; Test the GlobalMerge pass. Check that the pass does not crash when using
 ; multiple address spaces.
 

Modified: llvm/trunk/test/CodeGen/ARM/global-merge.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/global-merge.ll?rev=233024&r1=233023&r2=233024&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/global-merge.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/global-merge.ll Mon Mar 23 16:17:36 2015
@@ -1,4 +1,4 @@
-; RUN: llc < %s -mtriple=thumb-apple-darwin -global-merge-on-const=true | FileCheck %s
+; RUN: llc < %s -mtriple=thumb-apple-darwin -O3 -global-merge-on-const=true | FileCheck %s
 ; Test the ARMGlobalMerge pass.  Use -march=thumb because it has a small
 ; value for the maximum offset (127).

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