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Make globalopt refine global variable alignment. 

llvm-svn: 100160
This commit is contained in:
Dan Gohman 2010-04-02 00:14:16 +00:00
parent cdf40bed1b
commit c671347fcb
2 changed files with 13 additions and 1 deletions
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8
llvm/lib/Transforms/IPO/GlobalOpt.cpp
View File

@ -1880,6 +1880,7 @@ bool GlobalOpt::OptimizeFunctions(Module &M) {
bool GlobalOpt::OptimizeGlobalVars(Module &M) {
bool Changed = false;
TargetData *TD = getAnalysisIfAvailable<TargetData>();
for (Module::global_iterator GVI = M.global_begin(), E = M.global_end();
GVI != E; ) {
GlobalVariable *GV = GVI++;
@ -1889,11 +1890,16 @@ bool GlobalOpt::OptimizeGlobalVars(Module &M) {
// Simplify the initializer.
if (GV->hasInitializer())
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(GV->getInitializer())) {
TargetData *TD = getAnalysisIfAvailable<TargetData>();
Constant *New = ConstantFoldConstantExpression(CE, TD);
if (New && New != CE)
GV->setInitializer(New);
}
// Refine the alignment value.
if (TD && GV->hasDefinitiveInitializer()) {
unsigned Align = TD->getPreferredAlignment(GV);
if (Align > GV->getAlignment())
GV->setAlignment(Align);
}
// Do more involved optimizations if the global is internal.
if (!GV->isConstant() && GV->hasLocalLinkage() &&
GV->hasInitializer())

6
llvm/test/Transforms/GlobalOpt/gv-align.ll Normal file
View File

@ -0,0 +1,6 @@
; RUN: opt -globalopt -S < %s | grep {, align 16}
; Globalopt should refine the alignment for global variables.
target datalayout = "e-p:64:64:64"
@a = global [4 x i32] [i32 2, i32 3, i32 4, i32 5 ]