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Fix PR3141 by ensuring that MemoryDependenceAnalysis::removeInstruction

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properly updates the reverse dependency map when it installs updated 
dependencies for instructions that depend on the removed instruction.

llvm-svn: 60222
This commit is contained in:
Chris Lattner 2008-11-28 22:51:08 +00:00
parent aedb1385c2
commit 494758e720
2 changed files with 44 additions and 12 deletions
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40
lib/Analysis/MemoryDependenceAnalysis.cpp
View File

@ -545,6 +545,7 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) {
if (IsConfirmed) {
// If we have a confirmed non-local flag, use it.
if (LocalDepInst == NonLocal || LocalDepInst == None) {
// The only time this dependency is confirmed is if it is non-local.
NewDependency = LocalDepInst;
NewDependencyConfirmed = true;
} else {
@ -565,18 +566,34 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) {
if (NewDependency == 0)
NewDependency = next(BasicBlock::iterator(RemInst));
SmallPtrSet<Instruction*, 4>& set = reverseDep[RemInst];
for (SmallPtrSet<Instruction*, 4>::iterator I = set.begin(), E = set.end();
I != E; ++I) {
// Insert the new dependencies
// Mark it as unconfirmed as long as it is not the non-local flag
depGraphLocal[*I] = std::make_pair(NewDependency, NewDependencyConfirmed);
// Loop over all of the things that depend on the instruction we're removing.
//
reverseDepMapType::iterator ReverseDepIt = reverseDep.find(RemInst);
if (ReverseDepIt != reverseDep.end()) {
SmallPtrSet<Instruction*, 4> &ReverseDeps = ReverseDepIt->second;
for (SmallPtrSet<Instruction*, 4>::iterator I = ReverseDeps.begin(),
E = ReverseDeps.end(); I != E; ++I) {
Instruction *InstDependingOnRemInst = *I;
// If we thought the instruction depended on itself (possible for
// unconfirmed dependencies) ignore the update.
if (InstDependingOnRemInst == RemInst) continue;
// Insert the new dependencies.
depGraphLocal[InstDependingOnRemInst] =
std::make_pair(NewDependency, NewDependencyConfirmed);
// If our NewDependency is an instruction, make sure to remember that new
// things depend on it.
if (NewDependency != NonLocal && NewDependency != None)
reverseDep[NewDependency].insert(InstDependingOnRemInst);
}
reverseDep.erase(RemInst);
}
reverseDep.erase(RemInst);
if (reverseDepNonLocal.count(RemInst)) {
SmallPtrSet<Instruction*, 4>& set = reverseDepNonLocal[RemInst];
ReverseDepIt = reverseDepNonLocal.find(RemInst);
if (ReverseDepIt != reverseDepNonLocal.end()) {
SmallPtrSet<Instruction*, 4>& set = ReverseDepIt->second;
for (SmallPtrSet<Instruction*, 4>::iterator I = set.begin(), E = set.end();
I != E; ++I)
for (DenseMap<BasicBlock*, Value*>::iterator DI =
@ -584,10 +601,9 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction *RemInst) {
DI != DE; ++DI)
if (DI->second == RemInst)
DI->second = Dirty;
reverseDepNonLocal.erase(RemInst);
}
reverseDepNonLocal.erase(RemInst);
depGraphNonLocal.erase(RemInst);
getAnalysis<AliasAnalysis>().deleteValue(RemInst);

16
test/Transforms/DeadStoreElimination/2008-11-28-MemDepUpdate.ll Normal file
View File

@ -0,0 +1,16 @@
; RUN: llvm-as < %s | opt -dse | llvm-dis
; PR3141
%struct.ada__tags__dispatch_table = type { [1 x i32] }
%struct.f393a00_1__object = type { %struct.ada__tags__dispatch_table*, i8 }
%struct.f393a00_2__windmill = type { %struct.f393a00_1__object, i16 }
define void @f393a00_2__swap(%struct.f393a00_2__windmill* %a, %struct.f393a00_2__windmill* %b) {
entry:
%t = alloca %struct.f393a00_2__windmill ; <%struct.f393a00_2__windmill*> [#uses=1]
%0 = getelementptr %struct.f393a00_2__windmill* %t, i32 0, i32 0, i32 0 ; <%struct.ada__tags__dispatch_table**> [#uses=1]
%1 = load %struct.ada__tags__dispatch_table** null, align 4 ; <%struct.ada__tags__dispatch_table*> [#uses=1]
%2 = load %struct.ada__tags__dispatch_table** %0, align 8 ; <%struct.ada__tags__dispatch_table*> [#uses=1]
store %struct.ada__tags__dispatch_table* %2, %struct.ada__tags__dispatch_table** null, align 4
store %struct.ada__tags__dispatch_table* %1, %struct.ada__tags__dispatch_table** null, align 4
ret void
}