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Merge isObjectPointerWithTrustworthySize with getPointerSize. Use it when 

looking at the size of the pointee. Fixes PR11390!

llvm-svn: 144773
This commit is contained in:
Nick Lewycky 2011-11-16 03:49:48 +00:00
parent b8c55a5339
commit c7f1e7993c
2 changed files with 58 additions and 30 deletions
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50
llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
View File

@ -274,43 +274,35 @@ static Value *getStoredPointerOperand(Instruction *I) {
}
}
static uint64_t getPointerSize(Value *V, AliasAnalysis &AA) {
static uint64_t getPointerSize(const Value *V, AliasAnalysis &AA) {
const TargetData *TD = AA.getTargetData();
if (CallInst *CI = dyn_cast<CallInst>(V)) {
assert(isMalloc(CI) && "Expected Malloc call!");
if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getArgOperand(0)))
if (const CallInst *CI = extractMallocCall(V)) {
if (const ConstantInt *C = dyn_cast<ConstantInt>(CI->getArgOperand(0)))
return C->getZExtValue();
return AliasAnalysis::UnknownSize;
}
if (TD == 0)
return AliasAnalysis::UnknownSize;
if (AllocaInst *A = dyn_cast<AllocaInst>(V)) {
if (const AllocaInst *A = dyn_cast<AllocaInst>(V)) {
// Get size information for the alloca
if (ConstantInt *C = dyn_cast<ConstantInt>(A->getArraySize()))
if (const ConstantInt *C = dyn_cast<ConstantInt>(A->getArraySize()))
return C->getZExtValue() * TD->getTypeAllocSize(A->getAllocatedType());
return AliasAnalysis::UnknownSize;
}
assert(isa<Argument>(V) && "Expected AllocaInst, malloc call or Argument!");
PointerType *PT = cast<PointerType>(V->getType());
return TD->getTypeAllocSize(PT->getElementType());
}
if (const Argument *A = dyn_cast<Argument>(V)) {
if (A->hasByValAttr())
if (PointerType *PT = dyn_cast<PointerType>(A->getType()))
return TD->getTypeAllocSize(PT->getElementType());
}
/// isObjectPointerWithTrustworthySize - Return true if the specified Value* is
/// pointing to an object with a pointer size we can trust.
static bool isObjectPointerWithTrustworthySize(const Value *V) {
if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
return !AI->isArrayAllocation();
if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
return !GV->mayBeOverridden();
if (const Argument *A = dyn_cast<Argument>(V))
return A->hasByValAttr();
if (isMalloc(V))
return true;
return false;
if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
if (!GV->mayBeOverridden())
return TD->getTypeAllocSize(GV->getType()->getElementType());
}
return AliasAnalysis::UnknownSize;
}
namespace {
@ -329,8 +321,8 @@ namespace {
static OverwriteResult isOverwrite(const AliasAnalysis::Location &Later,
const AliasAnalysis::Location &Earlier,
AliasAnalysis &AA,
int64_t& EarlierOff,
int64_t& LaterOff) {
int64_t &EarlierOff,
int64_t &LaterOff) {
const Value *P1 = Earlier.Ptr->stripPointerCasts();
const Value *P2 = Later.Ptr->stripPointerCasts();
@ -377,12 +369,10 @@ static OverwriteResult isOverwrite(const AliasAnalysis::Location &Later,
return OverwriteUnknown;
// If the "Later" store is to a recognizable object, get its size.
if (isObjectPointerWithTrustworthySize(UO2)) {
uint64_t ObjectSize =
TD.getTypeAllocSize(cast<PointerType>(UO2->getType())->getElementType());
uint64_t ObjectSize = getPointerSize(UO2, AA);
if (ObjectSize != AliasAnalysis::UnknownSize)
if (ObjectSize == Later.Size && ObjectSize >= Earlier.Size)
return OverwriteComplete;
}
// Okay, we have stores to two completely different pointers. Try to
// decompose the pointer into a "base + constant_offset" form. If the base

38
llvm/test/Transforms/DeadStoreElimination/pr11390.ll Normal file
View File

@ -0,0 +1,38 @@
; RUN: opt -basicaa -dse -S -o - | FileCheck %s
; PR11390
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-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define fastcc void @cat_domain(i8* nocapture %name, i8* nocapture %domain, i8**
nocapture %s) nounwind uwtable {
entry:
%call = tail call i64 @strlen(i8* %name) nounwind readonly
%call1 = tail call i64 @strlen(i8* %domain) nounwind readonly
%add = add i64 %call, 1
%add2 = add i64 %add, %call1
%add3 = add i64 %add2, 1
%call4 = tail call noalias i8* @malloc(i64 %add3) nounwind
store i8* %call4, i8** %s, align 8
%tobool = icmp eq i8* %call4, null
br i1 %tobool, label %return, label %if.end
if.end: ; preds = %entry
tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %call4, i8* %name, i64 %call, i32 1, i1 false)
%arrayidx = getelementptr inbounds i8* %call4, i64 %call
store i8 46, i8* %arrayidx, align 1
; CHECK: store i8 46
%add.ptr5 = getelementptr inbounds i8* %call4, i64 %add
tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %add.ptr5, i8* %domain, i64 %call1, i32 1, i1 false)
%arrayidx8 = getelementptr inbounds i8* %call4, i64 %add2
store i8 0, i8* %arrayidx8, align 1
br label %return
return: ; preds = %if.end, %entry
ret void
}
declare i64 @strlen(i8* nocapture) nounwind readonly
declare noalias i8* @malloc(i64) nounwind
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind