The cost of splitting a large vector instruction is not being taken into account by the getUserCost function. This was leading to some loops being over unrolled. The cost of a vector instruction is now being multiplied by the cost of the type legalization. This will return a more accurate cost.

Committing on behalf on Brad Nemanich (brad.nemanich@ibm.com)

Differential Revision: https://reviews.llvm.org/D38961

llvm-svn: 316174
This commit is contained in:
Graham Yiu 2017-10-19 18:16:31 +00:00
parent 6c3c02a3bd
commit 488782efa3
3 changed files with 87 additions and 0 deletions

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@ -189,6 +189,17 @@ int PPCTTIImpl::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
return PPCTTIImpl::getIntImmCost(Imm, Ty);
}
unsigned PPCTTIImpl::getUserCost(const User *U,
ArrayRef<const Value *> Operands) {
if (U->getType()->isVectorTy()) {
// Instructions that need to be split should cost more.
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, U->getType());
return LT.first * BaseT::getUserCost(U, Operands);
}
return BaseT::getUserCost(U, Operands);
}
void PPCTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
TTI::UnrollingPreferences &UP) {
if (ST->getDarwinDirective() == PPC::DIR_A2) {

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@ -51,6 +51,8 @@ public:
int getIntImmCost(Intrinsic::ID IID, unsigned Idx, const APInt &Imm,
Type *Ty);
unsigned getUserCost(const User *U, ArrayRef<const Value *> Operands);
TTI::PopcntSupportKind getPopcntSupport(unsigned TyWidth);
void getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
TTI::UnrollingPreferences &UP);

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@ -0,0 +1,74 @@
; RUN: opt < %s -S -mtriple=powerpc64le-unknown-linux-gnu -mcpu=pwr8 -loop-unroll | FileCheck %s
; RUN: opt < %s -S -mtriple=powerpc64le-unknown-linux-gnu -mcpu=pwr9 -loop-unroll | FileCheck %s
target datalayout = "e-m:e-i64:64-n32:64"
target triple = "powerpc64le-unknown-linux-gnu"
; Function Attrs: norecurse nounwind
define i8* @f(i8* returned %s, i32 zeroext %x, i32 signext %k) local_unnamed_addr #0 {
entry:
%cmp10 = icmp sgt i32 %k, 0
br i1 %cmp10, label %for.body.lr.ph, label %for.end
for.body.lr.ph: ; preds = %entry
%wide.trip.count = zext i32 %k to i64
%min.iters.check = icmp ult i32 %k, 16
br i1 %min.iters.check, label %for.body.preheader, label %vector.ph
vector.ph: ; preds = %for.body.lr.ph
%n.vec = and i64 %wide.trip.count, 4294967280
%broadcast.splatinsert = insertelement <16 x i32> undef, i32 %x, i32 0
%broadcast.splat = shufflevector <16 x i32> %broadcast.splatinsert, <16 x i32> undef, <16 x i32> zeroinitializer
br label %vector.body
vector.body: ; preds = %vector.body, %vector.ph
%index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
%vec.ind12 = phi <16 x i32> [ <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>, %vector.ph ], [ %vec.ind.next13, %vector.body ]
%0 = shl <16 x i32> <i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1>, %vec.ind12
%1 = and <16 x i32> %0, %broadcast.splat
%2 = icmp eq <16 x i32> %1, zeroinitializer
%3 = select <16 x i1> %2, <16 x i8> <i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48, i8 48>, <16 x i8> <i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49, i8 49>
%4 = getelementptr inbounds i8, i8* %s, i64 %index
%5 = bitcast i8* %4 to <16 x i8>*
store <16 x i8> %3, <16 x i8>* %5, align 1
%index.next = add i64 %index, 16
%vec.ind.next13 = add <16 x i32> %vec.ind12, <i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16, i32 16>
%6 = icmp eq i64 %index.next, %n.vec
br i1 %6, label %middle.block, label %vector.body
middle.block: ; preds = %vector.body
%cmp.n = icmp eq i64 %n.vec, %wide.trip.count
br i1 %cmp.n, label %for.end, label %for.body.preheader
for.body.preheader: ; preds = %middle.block, %for.body.lr.ph
%indvars.iv.ph = phi i64 [ 0, %for.body.lr.ph ], [ %n.vec, %middle.block ]
br label %for.body
for.body: ; preds = %for.body.preheader, %for.body
%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ %indvars.iv.ph, %for.body.preheader ]
%7 = trunc i64 %indvars.iv to i32
%shl = shl i32 1, %7
%and = and i32 %shl, %x
%tobool = icmp eq i32 %and, 0
%conv = select i1 %tobool, i8 48, i8 49
%arrayidx = getelementptr inbounds i8, i8* %s, i64 %indvars.iv
store i8 %conv, i8* %arrayidx, align 1
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%exitcond = icmp eq i64 %indvars.iv.next, %wide.trip.count
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body, %middle.block, %entry
%idxprom1 = sext i32 %k to i64
%arrayidx2 = getelementptr inbounds i8, i8* %s, i64 %idxprom1
store i8 0, i8* %arrayidx2, align 1
ret i8* %s
}
; CHECK-LABEL: vector.body
; CHECK: shl
; CHECK-NEXT: and
; CHECK: shl
; CHECK-NEXT: and
; CHECK: label %vector.body