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[ScopDetect] Include zero-iteration loops in loop count.

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Loop with zero iteration are, syntactically, loops. They have been
excluded from the loop counter even for the non-profitable counters.
This seems to be unintentially as the sentinel value of '0' minimal
iterations does exclude such loops.

Fix by never considering the iteration count when the sentinel
value of 0 is found.

This makes the recently added NumTotalLoops couter redundant
with NumLoopsOverall, which now is equivalent. Hence, NumTotalLoops
is removed as well.

Note: The test case 'ScopDetect/statistics.ll' effectively does not
check profitability, because -polly-process-unprofitable is passed
to all test cases.

llvm-svn: 311551
This commit is contained in:
Michael Kruse 2017-08-23 13:29:59 +00:00
parent 99fba1fd52
commit 7fac28fa4f
2 changed files with 41 additions and 26 deletions
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23
polly/lib/Analysis/ScopDetection.cpp
View File

@ -212,8 +212,6 @@ StringRef polly::PollySkipFnAttr = "polly.skip.fn";
//===----------------------------------------------------------------------===//
// Statistics.
STATISTIC(NumTotalLoops, "Number of loops (in- or out of scops, in any "
"function processed by Polly)");
STATISTIC(NumScopRegions, "Number of scops");
STATISTIC(NumLoopsInScop, "Number of loops in scops");
STATISTIC(NumScopsDepthOne, "Number of scops with maximal loop depth 1");
@ -305,17 +303,6 @@ static bool doesStringMatchAnyRegex(StringRef Str,
//===----------------------------------------------------------------------===//
// ScopDetection.
static void countTotalLoops(Loop *L) {
NumTotalLoops++;
for (Loop *SubLoop : L->getSubLoops())
countTotalLoops(SubLoop);
}
static void countTotalLoops(LoopInfo &LI) {
for (Loop *L : LI)
countTotalLoops(L);
}
ScopDetection::ScopDetection(Function &F, const DominatorTree &DT,
ScalarEvolution &SE, LoopInfo &LI, RegionInfo &RI,
AliasAnalysis &AA, OptimizationRemarkEmitter &ORE)
@ -338,7 +325,6 @@ ScopDetection::ScopDetection(Function &F, const DominatorTree &DT,
findScops(*TopRegion);
countTotalLoops(LI);
NumScopRegions += ValidRegions.size();
// Prune non-profitable regions.
@ -1238,10 +1224,11 @@ ScopDetection::countBeneficialSubLoops(Loop *L, ScalarEvolution &SE,
int NumLoops = 1;
int MaxLoopDepth = 1;
if (auto *TripCountC = dyn_cast<SCEVConstant>(TripCount))
if (TripCountC->getType()->getScalarSizeInBits() <= 64)
if (TripCountC->getValue()->getZExtValue() <= MinProfitableTrips)
NumLoops -= 1;
if (MinProfitableTrips > 0)
if (auto *TripCountC = dyn_cast<SCEVConstant>(TripCount))
if (TripCountC->getType()->getScalarSizeInBits() <= 64)
if (TripCountC->getValue()->getZExtValue() <= MinProfitableTrips)
NumLoops -= 1;
for (auto &SubLoop : *L) {
LoopStats Stats = countBeneficialSubLoops(SubLoop, SE, MinProfitableTrips);

44
polly/test/ScopDetect/statistics.ll
View File

@ -2,20 +2,19 @@
; REQUIRES: asserts
; CHECK-DAG: 10 polly-detect - Number of loops (in- or out of scops, in any function processed by Polly)
; CHECK-DAG: 4 polly-detect - Maximal number of loops in scops (profitable scops only)
; CHECK-DAG: 4 polly-detect - Maximal number of loops in scops
; CHECK-DAG: 10 polly-detect - Number of loops in scops (profitable scops only)
; CHECK-DAG: 10 polly-detect - Number of loops in scops
; CHECK-DAG: 10 polly-detect - Number of total loops
; CHECK-DAG: 4 polly-detect - Number of scops (profitable scops only)
; CHECK-DAG: 11 polly-detect - Number of loops in scops (profitable scops only)
; CHECK-DAG: 11 polly-detect - Number of loops in scops
; CHECK-DAG: 11 polly-detect - Number of total loops
; CHECK-DAG: 5 polly-detect - Number of scops (profitable scops only)
; CHECK-DAG: 1 polly-detect - Number of scops with maximal loop depth 4 (profitable scops only)
; CHECK-DAG: 1 polly-detect - Number of scops with maximal loop depth 1 (profitable scops only)
; CHECK-DAG: 2 polly-detect - Number of scops with maximal loop depth 1 (profitable scops only)
; CHECK-DAG: 1 polly-detect - Number of scops with maximal loop depth 3 (profitable scops only)
; CHECK-DAG: 1 polly-detect - Number of scops with maximal loop depth 2 (profitable scops only)
; CHECK-DAG: 4 polly-detect - Number of scops
; CHECK-DAG: 5 polly-detect - Number of scops
; CHECK-DAG: 1 polly-detect - Number of scops with maximal loop depth 4
; CHECK-DAG: 1 polly-detect - Number of scops with maximal loop depth 1
; CHECK-DAG: 2 polly-detect - Number of scops with maximal loop depth 1
; CHECK-DAG: 1 polly-detect - Number of scops with maximal loop depth 3
; CHECK-DAG: 1 polly-detect - Number of scops with maximal loop depth 2
@ -45,6 +44,10 @@
; A[i + j + k + l] += i + j + k + l;
; }
;
; void foo_zero_iterations(float *S) {
; for (long i = 0; i < 0; i++)
; A[i] += i;
; }
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
define void @foo_1d(float* %A) {
@ -248,3 +251,28 @@ bb30: ; preds = %bb29
bb32: ; preds = %bb4
ret void
}
define void @foo_zero_iterations(float* %A) {
bb:
br label %bb1
bb1: ; preds = %bb6, %bb
%i.0 = phi i64 [ 0, %bb ], [ %tmp7, %bb6 ]
%exitcond = icmp ne i64 %i.0, 0
br i1 %exitcond, label %bb2, label %bb8
bb2: ; preds = %bb1
%tmp = sitofp i64 %i.0 to float
%tmp3 = getelementptr inbounds float, float* %A, i64 %i.0
%tmp4 = load float, float* %tmp3, align 4
%tmp5 = fadd float %tmp4, %tmp
store float %tmp5, float* %tmp3, align 4
br label %bb6
bb6: ; preds = %bb2
%tmp7 = add nuw nsw i64 %i.0, 1
br label %bb1
bb8: ; preds = %bb1
ret void
}