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Revert "peel loops with runtime small trip counts" 

This reverts commit r328854, it breaks some Hexagon tests.

llvm-svn: 328875
This commit is contained in:
Krzysztof Parzyszek 2018-03-30 16:55:44 +00:00
parent 74e2974ac6
commit fce30c2ba3
3 changed files with 1 additions and 51 deletions
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8
llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.cpp
View File

@ -44,14 +44,6 @@ HexagonTTIImpl::getPopcntSupport(unsigned IntTyWidthInBit) const {
void HexagonTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
TTI::UnrollingPreferences &UP) {
UP.Runtime = UP.Partial = true;
// Only try to peel innermost loops with small runtime trip counts.
if (L && L->empty() &&
SE.getSmallConstantTripCount(L) == 0 &&
SE.getSmallConstantMaxTripCount(L) > 0 &&
SE.getSmallConstantMaxTripCount(L) <= 5) {
UP.PeelCount = 2;
UP.AllowPeeling = true;
}
}
bool HexagonTTIImpl::shouldFavorPostInc() const {

7
llvm/lib/Transforms/Utils/LoopUnrollPeel.cpp
View File

@ -221,9 +221,6 @@ void llvm::computePeelCount(Loop *L, unsigned LoopSize,
TargetTransformInfo::UnrollingPreferences &UP,
unsigned &TripCount, ScalarEvolution &SE) {
assert(LoopSize > 0 && "Zero loop size is not allowed!");
// Save the UP.PeelCount value set by the target in
// TTI.getUnrollingPreferences or by the flag -unroll-peel-count.
unsigned TargetPeelCount = UP.PeelCount;
UP.PeelCount = 0;
if (!canPeel(L))
return;
@ -243,9 +240,7 @@ void llvm::computePeelCount(Loop *L, unsigned LoopSize,
SmallDenseMap<PHINode *, unsigned> IterationsToInvariance;
// Now go through all Phis to calculate their the number of iterations they
// need to become invariants.
// Start the max computation with the UP.PeelCount value set by the target
// in TTI.getUnrollingPreferences or by the flag -unroll-peel-count.
unsigned DesiredPeelCount = TargetPeelCount;
unsigned DesiredPeelCount = 0;
BasicBlock *BackEdge = L->getLoopLatch();
assert(BackEdge && "Loop is not in simplified form?");
for (auto BI = L->getHeader()->begin(); isa<PHINode>(&*BI); ++BI) {

37
llvm/test/Transforms/LoopUnroll/Hexagon/peel-small-loop.ll
View File

@ -1,37 +0,0 @@
; RUN: opt -loop-unroll -mtriple=hexagon -S < %s | FileCheck %s
; Check that the loop is peeled twice for Hexagon.
; CHECK: while.body.peel
; CHECK: while.body.peel2
%struct.STREAM = type { %union.anon, i32, i32 }
%union.anon = type { i32* }
define void @function(%struct.STREAM* nocapture readonly %b) local_unnamed_addr {
entry:
%bitPtr3 = getelementptr inbounds %struct.STREAM, %struct.STREAM* %b, i32 0, i32 2
%0 = load i32, i32* %bitPtr3, align 4
%cmp11 = icmp ult i32 %0, 32
br i1 %cmp11, label %while.body.preheader, label %do.end
while.body.preheader:
%value2 = getelementptr inbounds %struct.STREAM, %struct.STREAM* %b, i32 0, i32 1
%1 = load i32, i32* %value2, align 4
%w = getelementptr inbounds %struct.STREAM, %struct.STREAM* %b, i32 0, i32 0, i32 0
%2 = load i32*, i32** %w, align 4
br label %while.body
while.body:
%bitPtr.014 = phi i32 [ %add, %while.body ], [ %0, %while.body.preheader ]
%value.013 = phi i32 [ %shl, %while.body ], [ %1, %while.body.preheader ]
%ptr.012 = phi i32* [ %incdec.ptr, %while.body ], [ %2, %while.body.preheader ]
%add = add nuw i32 %bitPtr.014, 8
%shr = lshr i32 %value.013, 24
%incdec.ptr = getelementptr inbounds i32, i32* %ptr.012, i32 1
store i32 %shr, i32* %ptr.012, align 4
%shl = shl i32 %value.013, 8
%cmp = icmp ult i32 %add, 17
br i1 %cmp, label %while.body, label %do.end
do.end:
ret void
}