Add unnamed_addr when we can show that address of a global is not used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123834 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rafael Espindola 2011-01-19 16:32:21 +00:00
parent 348c975cb8
commit c4440e3e30
7 changed files with 103 additions and 20 deletions

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@ -40,6 +40,7 @@
using namespace llvm;
STATISTIC(NumMarked , "Number of globals marked constant");
STATISTIC(NumUnnamed , "Number of globals marked unnamed_addr");
STATISTIC(NumSRA , "Number of aggregate globals broken into scalars");
STATISTIC(NumHeapSRA , "Number of heap objects SRA'd");
STATISTIC(NumSubstitute,"Number of globals with initializers stored into them");
@ -55,6 +56,7 @@ STATISTIC(NumAliasesResolved, "Number of global aliases resolved");
STATISTIC(NumAliasesRemoved, "Number of global aliases eliminated");
namespace {
struct GlobalStatus;
struct GlobalOpt : public ModulePass {
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
}
@ -71,7 +73,10 @@ namespace {
bool OptimizeGlobalVars(Module &M);
bool OptimizeGlobalAliases(Module &M);
bool OptimizeGlobalCtorsList(GlobalVariable *&GCL);
bool ProcessInternalGlobal(GlobalVariable *GV,Module::global_iterator &GVI);
bool ProcessGlobal(GlobalVariable *GV,Module::global_iterator &GVI);
bool ProcessInternalGlobal(GlobalVariable *GV,Module::global_iterator &GVI,
const SmallPtrSet<const PHINode*, 16> &PHIUsers,
const GlobalStatus &GS);
};
}
@ -87,6 +92,9 @@ namespace {
/// about it. If we find out that the address of the global is taken, none of
/// this info will be accurate.
struct GlobalStatus {
/// isCompared - True if the global's address is used in a comparison.
bool isCompared;
/// isLoaded - True if the global is ever loaded. If the global isn't ever
/// loaded it can be deleted.
bool isLoaded;
@ -132,9 +140,10 @@ struct GlobalStatus {
/// HasPHIUser - Set to true if this global has a user that is a PHI node.
bool HasPHIUser;
GlobalStatus() : isLoaded(false), StoredType(NotStored), StoredOnceValue(0),
AccessingFunction(0), HasMultipleAccessingFunctions(false),
HasNonInstructionUser(false), HasPHIUser(false) {}
GlobalStatus() : isCompared(false), isLoaded(false), StoredType(NotStored),
StoredOnceValue(0), AccessingFunction(0),
HasMultipleAccessingFunctions(false), HasNonInstructionUser(false),
HasPHIUser(false) {}
};
}
@ -228,7 +237,7 @@ static bool AnalyzeGlobal(const Value *V, GlobalStatus &GS,
if (AnalyzeGlobal(I, GS, PHIUsers)) return true;
GS.HasPHIUser = true;
} else if (isa<CmpInst>(I)) {
// Nothing to analyse.
GS.isCompared = true;
} else if (isa<MemTransferInst>(I)) {
const MemTransferInst *MTI = cast<MemTransferInst>(I);
if (MTI->getArgOperand(0) == V)
@ -1691,10 +1700,12 @@ static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) {
/// ProcessInternalGlobal - Analyze the specified global variable and optimize
/// it if possible. If we make a change, return true.
bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV,
Module::global_iterator &GVI) {
SmallPtrSet<const PHINode*, 16> PHIUsers;
GlobalStatus GS;
bool GlobalOpt::ProcessGlobal(GlobalVariable *GV,
Module::global_iterator &GVI) {
if (!GV->hasLocalLinkage())
return false;
// Do more involved optimizations if the global is internal.
GV->removeDeadConstantUsers();
if (GV->use_empty()) {
@ -1704,9 +1715,29 @@ bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV,
return true;
}
SmallPtrSet<const PHINode*, 16> PHIUsers;
GlobalStatus GS;
if (AnalyzeGlobal(GV, GS, PHIUsers))
return false;
if (!GS.isCompared && !GV->hasUnnamedAddr()) {
GV->setUnnamedAddr(true);
NumUnnamed++;
}
if (GV->isConstant() || !GV->hasInitializer())
return false;
return ProcessInternalGlobal(GV, GVI, PHIUsers, GS);
}
/// ProcessInternalGlobal - Analyze the specified global variable and optimize
/// it if possible. If we make a change, return true.
bool GlobalOpt::ProcessInternalGlobal(GlobalVariable *GV,
Module::global_iterator &GVI,
const SmallPtrSet<const PHINode*, 16> &PHIUsers,
const GlobalStatus &GS) {
// If this is a first class global and has only one accessing function
// and this function is main (which we know is not recursive we can make
// this global a local variable) we replace the global with a local alloca
@ -1903,10 +1934,8 @@ bool GlobalOpt::OptimizeGlobalVars(Module &M) {
if (New && New != CE)
GV->setInitializer(New);
}
// Do more involved optimizations if the global is internal.
if (!GV->isConstant() && GV->hasLocalLinkage() &&
GV->hasInitializer())
Changed |= ProcessInternalGlobal(GV, GVI);
Changed |= ProcessGlobal(GV, GVI);
}
return Changed;
}

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@ -2,9 +2,9 @@
; alignments. Elements 0 and 2 must be 16-byte aligned, and element
; 1 must be at least 8 byte aligned (but could be more).
; RUN: opt < %s -globalopt -S | grep {@G.0 = internal global .*align 16}
; RUN: opt < %s -globalopt -S | grep {@G.1 = internal global .*align 8}
; RUN: opt < %s -globalopt -S | grep {@G.2 = internal global .*align 16}
; RUN: opt < %s -globalopt -S | grep {@G.0 = internal unnamed_addr global .*align 16}
; RUN: opt < %s -globalopt -S | grep {@G.1 = internal unnamed_addr global .*align 8}
; RUN: opt < %s -globalopt -S | grep {@G.2 = internal unnamed_addr global .*align 16}
; rdar://5891920
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-f64:32:32-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"

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@ -1,4 +1,4 @@
; RUN: opt < %s -globalopt -S | grep {@X = internal global i32}
; RUN: opt < %s -globalopt -S | grep {@X = internal unnamed_addr global i32}
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
target triple = "i386-apple-darwin7"
@X = internal global i32* null ; <i32**> [#uses=2]

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@ -8,7 +8,7 @@ target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f3
target triple = "x86_64-apple-darwin10.0"
@TOP = internal global i64* null ; <i64**> [#uses=2]
; CHECK: @TOP = internal global i64* null
; CHECK: @TOP = internal unnamed_addr global i64* null
@channelColumns = internal global i64 0 ; <i64*> [#uses=2]
; Derived from @DescribeChannel() in yacr2

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@ -1,5 +1,5 @@
; RUN: opt < %s -globalopt -S > %t
; RUN: grep {@Y = internal global \\\[3 x \[%\]struct.X\\\] zeroinitializer} %t
; RUN: grep {@Y = internal unnamed_addr global \\\[3 x \[%\]struct.X\\\] zeroinitializer} %t
; RUN: grep load %t | count 6
; RUN: grep {add i32 \[%\]a, \[%\]b} %t | count 3

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@ -1,5 +1,5 @@
; RUN: opt < %s -globalopt -S | \
; RUN: grep {G1 = internal constant}
; RUN: grep {G1 = internal unnamed_addr constant}
@G1 = internal global [58 x i8] c"asdlfkajsdlfkajsd;lfkajds;lfkjasd;flkajsd;lkfja;sdlkfjasd\00" ; <[58 x i8]*> [#uses=1]

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@ -0,0 +1,54 @@
; RUN: opt %s -globalopt -S | FileCheck %s
@a = internal global i32 0, align 4
@b = internal global i32 0, align 4
@c = internal global i32 0, align 4
@d = internal constant [4 x i8] c"foo\00", align 1
; CHECK: @a = internal global i32 0, align 4
; CHECK: @b = internal global i32 0, align 4
; CHECK: @c = internal unnamed_addr global i32 0, align 4
; CHECK: @d = internal unnamed_addr constant [4 x i8] c"foo\00", align 1
define i1 @bah(i64 %i) nounwind readonly optsize ssp {
entry:
%arrayidx4 = getelementptr inbounds [4 x i8]* @d, i64 0, i64 %i
%tmp5 = load i8* %arrayidx4, align 1
%cmp = icmp eq i8 %tmp5, 42
ret i1 %cmp
}
define void @baz(i32 %x) {
entry:
store i32 %x, i32* @a, align 4
store i32 %x, i32* @b, align 4
store i32 %x, i32* @c, align 4
ret void
}
define i32 @foo(i32* %x) nounwind readnone optsize ssp {
entry:
%cmp = icmp eq i32* %x, @a
%conv = zext i1 %cmp to i32
ret i32 %conv
}
define i32 @bar() {
entry:
switch i64 ptrtoint (i32* @b to i64), label %sw.epilog [
i64 1, label %return
i64 0, label %return
]
sw.epilog:
ret i32 0
return:
ret i32 1
}
define i32 @zed() {
entry:
%tmp1 = load i32* @c, align 4
ret i32 %tmp1
}