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Revert "[LoopAccesses] Allow analysis to complete in the presence of uniform stores"

This reverts commit r234361.

It caused PR23157.

llvm-svn: 234387
This commit is contained in:
Adam Nemet 2015-04-08 04:16:55 +00:00
parent 3d144ea071
commit 8c21d63b1f
5 changed files with 11 additions and 134 deletions

View File

@ -432,13 +432,6 @@ public:
/// Only used in DEBUG build but we don't want NDEBUG-dependent ABI.
unsigned NumSymbolicStrides;
/// \brief Checks existence of store to invariant address inside loop.
/// If the loop has any store to invariant address, then it returns true,
/// else returns false.
bool hasStoreToLoopInvariantAddress() const {
return StoreToLoopInvariantAddress;
}
private:
/// \brief Analyze the loop. Substitute symbolic strides using Strides.
void analyzeLoop(const ValueToValueMap &Strides);
@ -476,10 +469,6 @@ private:
/// \brief Cache the result of analyzeLoop.
bool CanVecMem;
/// \brief Indicator for storing to uniform addresses.
/// If a loop has write to a loop invariant address then it should be true.
bool StoreToLoopInvariantAddress;
/// \brief The diagnostics report generated for the analysis. E.g. why we
/// couldn't analyze the loop.
Optional<LoopAccessReport> Report;

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@ -1044,8 +1044,16 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
for (I = Stores.begin(), IE = Stores.end(); I != IE; ++I) {
StoreInst *ST = cast<StoreInst>(*I);
Value* Ptr = ST->getPointerOperand();
// Check for store to loop invariant address.
StoreToLoopInvariantAddress = isUniform(Ptr);
if (isUniform(Ptr)) {
emitAnalysis(
LoopAccessReport(ST)
<< "write to a loop invariant address could not be vectorized");
DEBUG(dbgs() << "LAA: We don't allow storing to uniform addresses\n");
CanVecMem = false;
return;
}
// If we did *not* see this pointer before, insert it to the read-write
// list. At this phase it is only a 'write' list.
if (Seen.insert(Ptr).second) {
@ -1306,8 +1314,7 @@ LoopAccessInfo::LoopAccessInfo(Loop *L, ScalarEvolution *SE,
const ValueToValueMap &Strides)
: DepChecker(SE, L), NumComparisons(0), TheLoop(L), SE(SE), DL(DL),
TLI(TLI), AA(AA), DT(DT), NumLoads(0), NumStores(0),
MaxSafeDepDistBytes(-1U), CanVecMem(false),
StoreToLoopInvariantAddress(false) {
MaxSafeDepDistBytes(-1U), CanVecMem(false) {
if (canAnalyzeLoop())
analyzeLoop(Strides);
}
@ -1320,10 +1327,6 @@ void LoopAccessInfo::print(raw_ostream &OS, unsigned Depth) const {
OS.indent(Depth) << "Memory dependences are safe with run-time checks\n";
}
OS.indent(Depth) << "Store to invariant address was "
<< (StoreToLoopInvariantAddress ? "" : "not ")
<< "found in loop.\n";
if (Report)
OS.indent(Depth) << "Report: " << Report->str() << "\n";

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@ -4009,14 +4009,6 @@ bool LoopVectorizationLegality::canVectorizeMemory() {
if (!LAI->canVectorizeMemory())
return false;
if (LAI->hasStoreToLoopInvariantAddress()) {
emitAnalysis(
VectorizationReport()
<< "write to a loop invariant address could not be vectorized");
DEBUG(dbgs() << "LV: We don't allow storing to uniform addresses\n");
return false;
}
if (LAI->getNumRuntimePointerChecks() >
VectorizerParams::RuntimeMemoryCheckThreshold) {
emitAnalysis(VectorizationReport()

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@ -1,53 +0,0 @@
; RUN: opt < %s -loop-accesses -analyze | FileCheck %s
; Test to confirm LAA will find store to invariant address.
; Inner loop has a store to invariant address.
;
; for(; i < itr; i++) {
; for(; j < itr; j++) {
; var1[i] = var2[j] + var1[i];
; }
; }
; CHECK: Store to invariant address was found in loop.
; CHECK-NOT: Store to invariant address was not found in loop.
define i32 @foo(i32* nocapture %var1, i32* nocapture readonly %var2, i32 %itr) #0 {
entry:
%cmp20 = icmp eq i32 %itr, 0
br i1 %cmp20, label %for.end10, label %for.cond1.preheader
for.cond1.preheader: ; preds = %entry, %for.inc8
%indvars.iv23 = phi i64 [ %indvars.iv.next24, %for.inc8 ], [ 0, %entry ]
%j.022 = phi i32 [ %j.1.lcssa, %for.inc8 ], [ 0, %entry ]
%cmp218 = icmp ult i32 %j.022, %itr
br i1 %cmp218, label %for.body3.lr.ph, label %for.inc8
for.body3.lr.ph: ; preds = %for.cond1.preheader
%arrayidx5 = getelementptr inbounds i32, i32* %var1, i64 %indvars.iv23
%0 = zext i32 %j.022 to i64
br label %for.body3
for.body3: ; preds = %for.body3, %for.body3.lr.ph
%indvars.iv = phi i64 [ %0, %for.body3.lr.ph ], [ %indvars.iv.next, %for.body3 ]
%arrayidx = getelementptr inbounds i32, i32* %var2, i64 %indvars.iv
%1 = load i32, i32* %arrayidx, align 4
%2 = load i32, i32* %arrayidx5, align 4
%add = add nsw i32 %2, %1
store i32 %add, i32* %arrayidx5, align 4
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %itr
br i1 %exitcond, label %for.inc8, label %for.body3
for.inc8: ; preds = %for.body3, %for.cond1.preheader
%j.1.lcssa = phi i32 [ %j.022, %for.cond1.preheader ], [ %itr, %for.body3 ]
%indvars.iv.next24 = add nuw nsw i64 %indvars.iv23, 1
%lftr.wideiv25 = trunc i64 %indvars.iv.next24 to i32
%exitcond26 = icmp eq i32 %lftr.wideiv25, %itr
br i1 %exitcond26, label %for.end10, label %for.cond1.preheader
for.end10: ; preds = %for.inc8, %entry
ret i32 undef
}

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@ -1,54 +0,0 @@
; RUN: opt < %s -loop-accesses -analyze | FileCheck %s
; Test to confirm LAA will not find store to invariant address.
; Inner loop has no store to invariant address.
;
; for(; i < itr; i++) {
; for(; j < itr; j++) {
; var2[j] = var2[j] + var1[i];
; }
; }
; CHECK: Store to invariant address was not found in loop.
; CHECK-NOT: Store to invariant address was found in loop.
define i32 @foo(i32* nocapture readonly %var1, i32* nocapture %var2, i32 %itr) #0 {
entry:
%cmp20 = icmp eq i32 %itr, 0
br i1 %cmp20, label %for.end10, label %for.cond1.preheader
for.cond1.preheader: ; preds = %entry, %for.inc8
%indvars.iv23 = phi i64 [ %indvars.iv.next24, %for.inc8 ], [ 0, %entry ]
%j.022 = phi i32 [ %j.1.lcssa, %for.inc8 ], [ 0, %entry ]
%cmp218 = icmp ult i32 %j.022, %itr
br i1 %cmp218, label %for.body3.lr.ph, label %for.inc8
for.body3.lr.ph: ; preds = %for.cond1.preheader
%arrayidx5 = getelementptr inbounds i32, i32* %var1, i64 %indvars.iv23
%0 = zext i32 %j.022 to i64
br label %for.body3
for.body3: ; preds = %for.body3, %for.body3.lr.ph
%indvars.iv = phi i64 [ %0, %for.body3.lr.ph ], [ %indvars.iv.next, %for.body3 ]
%arrayidx = getelementptr inbounds i32, i32* %var2, i64 %indvars.iv
%1 = load i32, i32* %arrayidx, align 4
%2 = load i32, i32* %arrayidx5, align 4
%add = add nsw i32 %2, %1
store i32 %add, i32* %arrayidx, align 4
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %itr
br i1 %exitcond, label %for.inc8, label %for.body3
for.inc8: ; preds = %for.body3, %for.cond1.preheader
%j.1.lcssa = phi i32 [ %j.022, %for.cond1.preheader ], [ %itr, %for.body3 ]
%indvars.iv.next24 = add nuw nsw i64 %indvars.iv23, 1
%lftr.wideiv25 = trunc i64 %indvars.iv.next24 to i32
%exitcond26 = icmp eq i32 %lftr.wideiv25, %itr
br i1 %exitcond26, label %for.end10, label %for.cond1.preheader
for.end10: ; preds = %for.inc8, %entry
ret i32 undef
}