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Fix PR3358, a really nasty bug where recursive phi translated

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analyses could be run without the caches properly sorted.  This
can fix all sorts of weirdness.  Many thanks to Bill for coming
up with the 'issorted' verification idea.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62757 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2009-01-22 07:04:01 +00:00
parent f9eb2d8aef
commit 12a7db3830
2 changed files with 91 additions and 3 deletions
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39
lib/Analysis/MemoryDependenceAnalysis.cpp
View File

@ -326,6 +326,19 @@ MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) {
return LocalCache;
}
#ifndef NDEBUG
/// AssertSorted - This method is used when -debug is specified to verify that
/// cache arrays are properly kept sorted.
static void AssertSorted(MemoryDependenceAnalysis::NonLocalDepInfo &Cache,
int Count = -1) {
if (Count == -1) Count = Cache.size();
if (Count == 0) return;
for (unsigned i = 1; i != unsigned(Count); ++i)
assert(Cache[i-1] <= Cache[i] && "Cache isn't sorted!");
}
#endif
/// getNonLocalCallDependency - Perform a full dependency query for the
/// specified call, returning the set of blocks that the value is
/// potentially live across. The returned set of results will include a
@ -386,6 +399,7 @@ MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) {
SmallPtrSet<BasicBlock*, 64> Visited;
unsigned NumSortedEntries = Cache.size();
DEBUG(AssertSorted(Cache));
// Iterate while we still have blocks to update.
while (!DirtyBlocks.empty()) {
@ -398,6 +412,7 @@ MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) {
// Do a binary search to see if we already have an entry for this block in
// the cache set. If so, find it.
DEBUG(AssertSorted(Cache, NumSortedEntries));
NonLocalDepInfo::iterator Entry =
std::upper_bound(Cache.begin(), Cache.begin()+NumSortedEntries,
std::make_pair(DirtyBB, MemDepResult()));
@ -647,6 +662,7 @@ getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize,
// won't get any reuse from currently inserted values, because we don't
// revisit blocks after we insert info for them.
unsigned NumSortedEntries = Cache->size();
DEBUG(AssertSorted(*Cache));
while (!Worklist.empty()) {
BasicBlock *BB = Worklist.pop_back_val();
@ -659,6 +675,7 @@ getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize,
// Get the dependency info for Pointer in BB. If we have cached
// information, we will use it, otherwise we compute it.
DEBUG(AssertSorted(*Cache, NumSortedEntries));
MemDepResult Dep = GetNonLocalInfoForBlock(Pointer, PointeeSize, isLoad,
BB, Cache, NumSortedEntries);
@ -705,7 +722,7 @@ getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize,
// If this is directly a PHI node, just use the incoming values for each
// pred as the phi translated version.
if (PHINode *PtrPHI = dyn_cast<PHINode>(PtrInst)) {
for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI){
for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) {
BasicBlock *Pred = *PI;
Value *PredPtr = PtrPHI->getIncomingValueForBlock(Pred);
@ -728,6 +745,21 @@ getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize,
// treat this as a phi translation failure.
goto PredTranslationFailure;
}
// We may have added values to the cache list before this PHI
// translation. If so, we haven't done anything to ensure that the
// cache remains sorted. Sort it now (if needed) so that recursive
// invocations of getNonLocalPointerDepFromBB that could reuse the cache
// value will only see properly sorted cache arrays.
if (NumSortedEntries != Cache->size()) {
std::sort(Cache->begin(), Cache->end());
NumSortedEntries = Cache->size();
}
// FIXME: it is entirely possible that PHI translating will end up with
// the same value. Consider PHI translating something like:
// X = phi [x, bb1], [y, bb2]. PHI translating for bb1 doesn't *need*
// to recurse here, pedantically speaking.
// If we have a problem phi translating, fall through to the code below
// to handle the failure condition.
@ -739,7 +771,8 @@ getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize,
// Refresh the CacheInfo/Cache pointer so that it isn't invalidated.
CacheInfo = &NonLocalPointerDeps[CacheKey];
Cache = &CacheInfo->second;
NumSortedEntries = Cache->size();
// Since we did phi translation, the "Cache" set won't contain all of the
// results for the query. This is ok (we can still use it to accelerate
// specific block queries) but we can't do the fastpath "return all
@ -817,7 +850,7 @@ getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize,
// Added many values, do a full scale sort.
std::sort(Cache->begin(), Cache->end());
}
DEBUG(AssertSorted(*Cache));
return false;
}

55
test/Transforms/GVN/2009-01-21-SortInvalidation.ll Normal file
View File

@ -0,0 +1,55 @@
; RUN: llvm-as < %s | opt -gvn | llvm-dis
; PR3358
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"
target triple = "x86_64-unknown-linux-gnu"
%struct.re_pattern_buffer = type { i8*, i64, i64, i64, i8*, i8*, i64, i8 }
%struct.re_registers = type { i32, i32*, i32* }
define fastcc i32 @byte_re_match_2_internal(%struct.re_pattern_buffer* nocapture %bufp, i8* %string1, i32 %size1, i8* %string2, i32 %size2, i32 %pos, %struct.re_registers* %regs, i32 %stop) nounwind {
entry:
br label %bb159
succeed_label: ; preds = %bb159
ret i32 0
bb159: ; preds = %bb664, %bb554, %bb159, %bb159, %bb159, %entry
%d.0 = phi i8* [ null, %entry ], [ %d.0, %bb159 ], [ %d.0, %bb554 ], [ %d.0, %bb159 ], [ %d.0, %bb159 ], [ %d.12, %bb664 ] ; <i8*> [#uses=5]
switch i32 0, label %bb661 [
i32 0, label %bb159
i32 1, label %succeed_label
i32 13, label %bb159
i32 14, label %bb159
i32 16, label %bb411
i32 24, label %bb622
i32 28, label %bb543
]
bb411: ; preds = %bb411, %bb159
br label %bb411
bb543: ; preds = %bb159
br i1 false, label %bb549, label %bb550
bb549: ; preds = %bb543
br label %bb554
bb550: ; preds = %bb543
br i1 false, label %bb554, label %bb552
bb552: ; preds = %bb550
%0 = load i8* %d.0, align 8 ; <i8> [#uses=0]
br label %bb554
bb554: ; preds = %bb552, %bb550, %bb549
br i1 false, label %bb159, label %bb661
bb622: ; preds = %bb622, %bb159
br label %bb622
bb661: ; preds = %bb554, %bb159
%d.12 = select i1 false, i8* null, i8* null ; <i8*> [#uses=1]
br label %bb664
bb664: ; preds = %bb664, %bb661
br i1 false, label %bb159, label %bb664
}