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-rw-r--r--llvm/include/llvm/IR/GlobalValue.h4
-rw-r--r--llvm/lib/CodeGen/CodeGenPrepare.cpp4
-rw-r--r--llvm/lib/IR/Globals.cpp44
-rw-r--r--llvm/lib/Transforms/Utils/Local.cpp20
-rw-r--r--llvm/test/CodeGen/ARM/memfunc.ll18
5 files changed, 25 insertions, 65 deletions
diff --git a/llvm/include/llvm/IR/GlobalValue.h b/llvm/include/llvm/IR/GlobalValue.h
index fa6469aa0ad..4fa4e7daeab 100644
--- a/llvm/include/llvm/IR/GlobalValue.h
+++ b/llvm/include/llvm/IR/GlobalValue.h
@@ -346,10 +346,6 @@ public:
return !(isDeclarationForLinker() || isWeakForLinker());
}
- // Returns true if the alignment of the value can be unilaterally
- // increased.
- bool canIncreaseAlignment() const;
-
/// This method unlinks 'this' from the containing module, but does not delete
/// it.
virtual void removeFromParent() = 0;
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index fd4ee464337..03e57787307 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -1742,8 +1742,8 @@ bool CodeGenPrepare::optimizeCallInst(CallInst *CI, bool& ModifiedDT) {
// over-aligning global variables that have an explicit section is
// forbidden.
GlobalVariable *GV;
- if ((GV = dyn_cast<GlobalVariable>(Val)) && GV->canIncreaseAlignment() &&
- GV->getAlignment() < PrefAlign &&
+ if ((GV = dyn_cast<GlobalVariable>(Val)) && GV->hasUniqueInitializer() &&
+ !GV->hasSection() && GV->getAlignment() < PrefAlign &&
DL->getTypeAllocSize(GV->getType()->getElementType()) >=
MinSize + Offset2)
GV->setAlignment(PrefAlign);
diff --git a/llvm/lib/IR/Globals.cpp b/llvm/lib/IR/Globals.cpp
index a61b62bd968..6159f93faf8 100644
--- a/llvm/lib/IR/Globals.cpp
+++ b/llvm/lib/IR/Globals.cpp
@@ -12,12 +12,11 @@
//
//===----------------------------------------------------------------------===//
+#include "llvm/IR/GlobalValue.h"
#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/Triple.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalAlias.h"
-#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
@@ -135,47 +134,6 @@ bool GlobalValue::isDeclaration() const {
return false;
}
-bool GlobalValue::canIncreaseAlignment() const {
- // Firstly, can only increase the alignment of a global if it
- // is a strong definition.
- if (!isStrongDefinitionForLinker())
- return false;
-
- // It also has to either not have a section defined, or, not have
- // alignment specified. (If it is assigned a section, the global
- // could be densely packed with other objects in the section, and
- // increasing the alignment could cause padding issues.)
- if (hasSection() && getAlignment() > 0)
- return false;
-
- // On ELF platforms, we're further restricted in that we can't
- // increase the alignment of any variable which might be emitted
- // into a shared library, and which is exported. If the main
- // executable accesses a variable found in a shared-lib, the main
- // exe actually allocates memory for and exports the symbol ITSELF,
- // overriding the symbol found in the library. That is, at link
- // time, the observed alignment of the variable is copied into the
- // executable binary. (A COPY relocation is also generated, to copy
- // the initial data from the shadowed variable in the shared-lib
- // into the location in the main binary, before running code.)
- //
- // And thus, even though you might think you are defining the
- // global, and allocating the memory for the global in your object
- // file, and thus should be able to set the alignment arbitrarily,
- // that's not actually true. Doing so can cause an ABI breakage; an
- // executable might have already been built with the previous
- // alignment of the variable, and then assuming an increased
- // alignment will be incorrect.
-
- // Conservatively assume ELF if there's no parent pointer.
- bool isELF =
- (!Parent || Triple(Parent->getTargetTriple()).isOSBinFormatELF());
- if (isELF && hasDefaultVisibility() && !hasLocalLinkage())
- return false;
-
- return true;
-}
-
//===----------------------------------------------------------------------===//
// GlobalVariable Implementation
//===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 91b3499407c..d2793e5ecb5 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -944,31 +944,37 @@ bool llvm::EliminateDuplicatePHINodes(BasicBlock *BB) {
static unsigned enforceKnownAlignment(Value *V, unsigned Align,
unsigned PrefAlign,
const DataLayout &DL) {
- assert(PrefAlign > Align);
-
V = V->stripPointerCasts();
if (AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
- assert(AI->getAlignment() <= Align);
// If the preferred alignment is greater than the natural stack alignment
// then don't round up. This avoids dynamic stack realignment.
if (DL.exceedsNaturalStackAlignment(PrefAlign))
return Align;
+ // If there is a requested alignment and if this is an alloca, round up.
+ if (AI->getAlignment() >= PrefAlign)
+ return AI->getAlignment();
AI->setAlignment(PrefAlign);
return PrefAlign;
}
if (auto *GO = dyn_cast<GlobalObject>(V)) {
- assert(GO->getAlignment() <= Align);
// If there is a large requested alignment and we can, bump up the alignment
// of the global. If the memory we set aside for the global may not be the
// memory used by the final program then it is impossible for us to reliably
// enforce the preferred alignment.
- if (!GO->canIncreaseAlignment())
+ if (!GO->isStrongDefinitionForLinker())
return Align;
- GO->setAlignment(PrefAlign);
- return PrefAlign;
+ if (GO->getAlignment() >= PrefAlign)
+ return GO->getAlignment();
+ // We can only increase the alignment of the global if it has no alignment
+ // specified or if it is not assigned a section. If it is assigned a
+ // section, the global could be densely packed with other objects in the
+ // section, increasing the alignment could cause padding issues.
+ if (!GO->hasSection() || GO->getAlignment() == 0)
+ GO->setAlignment(PrefAlign);
+ return GO->getAlignment();
}
return Align;
diff --git a/llvm/test/CodeGen/ARM/memfunc.ll b/llvm/test/CodeGen/ARM/memfunc.ll
index 46fef7629cc..66743f3e9d5 100644
--- a/llvm/test/CodeGen/ARM/memfunc.ll
+++ b/llvm/test/CodeGen/ARM/memfunc.ll
@@ -1,10 +1,10 @@
-; RUN: llc < %s -mtriple=armv7-apple-ios -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-IOS --check-prefix=CHECK
-; RUN: llc < %s -mtriple=thumbv7m-none-macho -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-DARWIN --check-prefix=CHECK
-; RUN: llc < %s -mtriple=arm-none-eabi -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-EABI --check-prefix=CHECK
-; RUN: llc < %s -mtriple=arm-none-eabihf -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-EABI --check-prefix=CHECK
-; RUN: llc < %s -mtriple=arm-none-androideabi -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-EABI --check-prefix=CHECK
-; RUN: llc < %s -mtriple=arm-none-gnueabi -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-GNUEABI --check-prefix=CHECK
-; RUN: llc < %s -mtriple=arm-none-gnueabihf -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-GNUEABI --check-prefix=CHECK
+; RUN: llc < %s -mtriple=armv7-apple-ios -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-IOS
+; RUN: llc < %s -mtriple=thumbv7m-none-macho -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-DARWIN
+; RUN: llc < %s -mtriple=arm-none-eabi -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-EABI
+; RUN: llc < %s -mtriple=arm-none-eabihf -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-EABI
+; RUN: llc < %s -mtriple=arm-none-androideabi -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-EABI
+; RUN: llc < %s -mtriple=arm-none-gnueabi -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-GNUEABI
+; RUN: llc < %s -mtriple=arm-none-gnueabihf -disable-post-ra -o - | FileCheck %s --check-prefix=CHECK-GNUEABI
define void @f1(i8* %dest, i8* %src) {
entry:
@@ -402,8 +402,8 @@ entry:
; CHECK: arr1:
; CHECK-IOS: .align 3
; CHECK-DARWIN: .align 2
-; CHECK-EABI-NOT: .align
-; CHECK-GNUEABI-NOT: .align
+; CHECK-EABI: .align 2
+; CHECK-GNUEABI: .align 2
; CHECK: arr2:
; CHECK: {{\.section.+foo,bar}}
; CHECK-NOT: .align
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