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[PowerPC] Fix PPCLoopPreIncPrep for depth > 1 loops

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This pass had the same problem as the data-prefetching pass: it was only
checking for depth == 1 loops in practice. Fix that, add some debugging
statements, and make sure that, when we grab an AddRec, it is for the loop we
expect.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234670 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2015-04-11 00:33:08 +00:00
parent c6665c6b72
commit ff49ef7838
2 changed files with 79 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
lib/Target/PowerPC/PPCLoopPreIncPrep.cpp
View File

@ -22,6 +22,7 @@
#define DEBUG_TYPE "ppc-loop-preinc-prep"
#include "PPC.h"
#include "PPCTargetMachine.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
@ -143,8 +144,10 @@ bool PPCLoopPreIncPrep::runOnFunction(Function &F) {
bool MadeChange = false;
for (LoopInfo::iterator I = LI->begin(), E = LI->end();
I != E; ++I) {
if (LI->empty())
return MadeChange;
for (auto I = df_begin(*LI->begin()), E = df_end(*LI->begin()); I != E; ++I) {
Loop *L = *I;
MadeChange |= runOnLoop(L);
}
@ -159,16 +162,15 @@ bool PPCLoopPreIncPrep::runOnLoop(Loop *L) {
if (!L->empty())
return MadeChange;
DEBUG(dbgs() << "PIP: Examining: " << *L << "\n");
BasicBlock *Header = L->getHeader();
const PPCSubtarget *ST =
TM ? TM->getSubtargetImpl(*Header->getParent()) : nullptr;
unsigned HeaderLoopPredCount = 0;
for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
PI != PE; ++PI) {
++HeaderLoopPredCount;
}
unsigned HeaderLoopPredCount =
std::distance(pred_begin(Header), pred_end(Header));
// Collect buckets of comparable addresses used by loads and stores.
typedef std::multimap<const SCEV *, Instruction *, SCEVLess> Bucket;
@ -205,9 +207,13 @@ bool PPCLoopPreIncPrep::runOnLoop(Loop *L) {
if (L->isLoopInvariant(PtrValue))
continue;
const SCEV *LSCEV = SE->getSCEV(PtrValue);
if (!isa<SCEVAddRecExpr>(LSCEV))
const SCEV *LSCEV = SE->getSCEVAtScope(PtrValue, L);
if (const SCEVAddRecExpr *LARSCEV = dyn_cast<SCEVAddRecExpr>(LSCEV)) {
if (LARSCEV->getLoop() != L)
continue;
} else {
continue;
}
bool FoundBucket = false;
for (unsigned i = 0, e = Buckets.size(); i != e; ++i)
@ -236,11 +242,16 @@ bool PPCLoopPreIncPrep::runOnLoop(Loop *L) {
// returns a value (which might contribute to determining the loop's
// iteration space), insert a new preheader for the loop.
if (!LoopPredecessor ||
!LoopPredecessor->getTerminator()->getType()->isVoidTy())
!LoopPredecessor->getTerminator()->getType()->isVoidTy()) {
LoopPredecessor = InsertPreheaderForLoop(L, this);
if (LoopPredecessor)
MadeChange = true;
}
if (!LoopPredecessor)
return MadeChange;
DEBUG(dbgs() << "PIP: Found " << Buckets.size() << " buckets\n");
SmallSet<BasicBlock *, 16> BBChanged;
for (unsigned i = 0, e = Buckets.size(); i != e; ++i) {
// The base address of each bucket is transformed into a phi and the others
@ -251,6 +262,10 @@ bool PPCLoopPreIncPrep::runOnLoop(Loop *L) {
if (!BasePtrSCEV->isAffine())
continue;
DEBUG(dbgs() << "PIP: Transforming: " << *BasePtrSCEV << "\n");
assert(BasePtrSCEV->getLoop() == L &&
"AddRec for the wrong loop?");
Instruction *MemI = Buckets[i].begin()->second;
Value *BasePtr = GetPointerOperand(MemI);
assert(BasePtr && "No pointer operand");
@ -271,6 +286,8 @@ bool PPCLoopPreIncPrep::runOnLoop(Loop *L) {
if (!isSafeToExpand(BasePtrStartSCEV, *SE))
continue;
DEBUG(dbgs() << "PIP: New start is: " << *BasePtrStartSCEV << "\n");
PHINode *NewPHI = PHINode::Create(I8PtrTy, HeaderLoopPredCount,
MemI->hasName() ? MemI->getName() + ".phi" : "",
Header->getFirstNonPHI());

52
test/CodeGen/PowerPC/pip-inner.ll Normal file
View File

@ -0,0 +1,52 @@
; RUN: llc < %s | FileCheck %s
target datalayout = "E-m:e-i64:64-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
; Function Attrs: nounwind
define void @foo(double* %x, double* nocapture readonly %y) #0 {
entry:
br label %for.cond1.preheader
for.cond1.preheader: ; preds = %for.end, %entry
%i.015 = phi i32 [ 0, %entry ], [ %inc7, %for.end ]
br label %for.body3
for.body3: ; preds = %for.body3, %for.cond1.preheader
%indvars.iv = phi i64 [ 0, %for.cond1.preheader ], [ %indvars.iv.next, %for.body3 ]
%arrayidx = getelementptr inbounds double, double* %y, i64 %indvars.iv
%0 = load double, double* %arrayidx, align 8
%add = fadd double %0, 1.000000e+00
%arrayidx5 = getelementptr inbounds double, double* %x, i64 %indvars.iv
store double %add, double* %arrayidx5, align 8
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%exitcond = icmp eq i64 %indvars.iv.next, 16000
br i1 %exitcond, label %for.end, label %for.body3
for.end: ; preds = %for.body3
tail call void @bar(double* %x) #2
%inc7 = add nuw nsw i32 %i.015, 1
%exitcond16 = icmp eq i32 %inc7, 1000
br i1 %exitcond16, label %for.end8, label %for.cond1.preheader
for.end8: ; preds = %for.end
ret void
; CHECK-LABEL: @foo
; CHECK: lfdu [[REG1:[0-9]+]], 8({{[0-9]+}})
; CHECK: fadd [[REG2:[0-9]+]], [[REG1]], {{[0-9]+}}
; CHECK: stfdu [[REG2]], 8({{[0-9]+}})
; CHECK: bdnz
; CHECK: bl bar
; CHECK-NEXT: nop
; CHECK: blr
}
declare void @bar(double*) #1
attributes #0 = { nounwind "target-cpu"="a2" }
attributes #1 = { "target-cpu"="a2" }
attributes #2 = { nounwind }