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It's not safe to tell SplitCriticalEdge to merge identical edges. It may delete the phi instruction that's being processed. 

llvm-svn: 43524
This commit is contained in:
Evan Cheng 2007-10-30 22:27:26 +00:00
parent d50c8bcef6
commit c2dbfee43f
2 changed files with 57 additions and 11 deletions
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20
llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
View File

@ -127,12 +127,12 @@ namespace {
/// StrideOrder - An ordering of the keys in IVUsesByStride that is stable:
/// We use this to iterate over the IVUsesByStride collection without being
/// dependent on random ordering of pointers in the process.
std::vector<SCEVHandle> StrideOrder;
SmallVector<SCEVHandle, 16> StrideOrder;
/// CastedValues - As we need to cast values to uintptr_t, this keeps track
/// of the casted version of each value. This is accessed by
/// getCastedVersionOf.
std::map<Value*, Value*> CastedPointers;
DenseMap<Value*, Value*> CastedPointers;
/// DeadInsts - Keep track of instructions we may have made dead, so that
/// we can remove them after we are done working.
@ -393,8 +393,7 @@ static bool IVUseShouldUsePostIncValue(Instruction *User, Instruction *IV,
// post-incremented value.
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (PN->getIncomingValue(i) == IV) {
SplitCriticalEdge(PN->getIncomingBlock(i), PN->getParent(), P,
true);
SplitCriticalEdge(PN->getIncomingBlock(i), PN->getParent(), P, false);
// Splitting the critical edge can reduce the number of entries in this
// PHI.
e = PN->getNumIncomingValues();
@ -627,7 +626,7 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEVHandle &NewBase,
// have multiple entries for the same predecessor. We use a map to make sure
// that a PHI node only has a single Value* for each predecessor (which also
// prevents us from inserting duplicate code in some blocks).
std::map<BasicBlock*, Value*> InsertedCode;
DenseMap<BasicBlock*, Value*> InsertedCode;
PHINode *PN = cast<PHINode>(Inst);
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
if (PN->getIncomingValue(i) == OperandValToReplace) {
@ -640,7 +639,7 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEVHandle &NewBase,
(PN->getParent() != L->getHeader() || !L->contains(PHIPred))) {
// First step, split the critical edge.
SplitCriticalEdge(PHIPred, PN->getParent(), P, true);
SplitCriticalEdge(PHIPred, PN->getParent(), P, false);
// Next step: move the basic block. In particular, if the PHI node
// is outside of the loop, and PredTI is in the loop, we want to
@ -1286,7 +1285,7 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
// Get a base value.
SCEVHandle Base = UsersToProcess[i].Base;
// Compact everything with this base to be consequetive with this one.
// Compact everything with this base to be consequtive with this one.
for (unsigned j = i+1; j != e; ++j) {
if (UsersToProcess[j].Base == Base) {
std::swap(UsersToProcess[i+1], UsersToProcess[j]);
@ -1355,10 +1354,9 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
// If we are reusing the iv, then it must be multiplied by a constant
// factor take advantage of addressing mode scale component.
if (RewriteFactor != 0) {
RewriteExpr =
SE->getMulExpr(SE->getIntegerSCEV(RewriteFactor,
RewriteExpr->getType()),
RewriteExpr);
RewriteExpr = SE->getMulExpr(SE->getIntegerSCEV(RewriteFactor,
RewriteExpr->getType()),
RewriteExpr);
// The common base is emitted in the loop preheader. But since we
// are reusing an IV, it has not been used to initialize the PHI node.

48
llvm/test/CodeGen/X86/2007-10-30-LSRCrash.ll Normal file
View File

@ -0,0 +1,48 @@
; RUN: llvm-as < %s | llc -march=x86
define i32 @unique(i8* %full, i32 %p, i32 %len, i32 %mode, i32 %verbos, i32 %flags) {
entry:
br i1 false, label %cond_true15, label %cond_next107
cond_true15: ; preds = %entry
br i1 false, label %bb98.preheader, label %bb
bb: ; preds = %cond_true15
ret i32 0
bb98.preheader: ; preds = %cond_true15
br i1 false, label %bb103, label %bb69.outer
bb76.split: ; preds = %bb69.outer.split.split, %bb69.us208
br i1 false, label %bb103, label %bb69.outer
bb69.outer: ; preds = %bb76.split, %bb98.preheader
%from.0.reg2mem.0.ph.rec = phi i32 [ %tmp75.rec, %bb76.split ], [ 0, %bb98.preheader ] ; <i32> [#uses=1]
%tmp75.rec = add i32 %from.0.reg2mem.0.ph.rec, 1 ; <i32> [#uses=2]
%tmp75 = getelementptr i8* null, i32 %tmp75.rec ; <i8*> [#uses=6]
br i1 false, label %bb69.us208, label %bb69.outer.split.split
bb69.us208: ; preds = %bb69.outer
switch i32 0, label %bb76.split [
i32 47, label %bb89
i32 58, label %bb89
i32 92, label %bb89
]
bb69.outer.split.split: ; preds = %bb69.outer
switch i8 0, label %bb76.split [
i8 47, label %bb89
i8 58, label %bb89
i8 92, label %bb89
]
bb89: ; preds = %bb69.outer.split.split, %bb69.outer.split.split, %bb69.outer.split.split, %bb69.us208, %bb69.us208, %bb69.us208
%tmp75.lcssa189 = phi i8* [ %tmp75, %bb69.us208 ], [ %tmp75, %bb69.us208 ], [ %tmp75, %bb69.us208 ], [ %tmp75, %bb69.outer.split.split ], [ %tmp75, %bb69.outer.split.split ], [ %tmp75, %bb69.outer.split.split ] ; <i8*> [#uses=0]
ret i32 0
bb103: ; preds = %bb76.split, %bb98.preheader
ret i32 0
cond_next107: ; preds = %entry
ret i32 0
}