Files
archived-llvm/test/Transforms/LoopVectorize/no_outside_user.ll
Anna Thomas 1464f16217 [LV] Teach about non header phis that have uses outside the loop
Summary:
This patch teaches the loop vectorizer to vectorize loops with non
header phis that have have outside uses.  This is because the iteration
dependence distance for these phis can be widened upto VF (similar to
how we do for induction/reduction) if they do not have a cyclic
dependence with header phis. When identifying reduction/induction/first
order recurrence header phis, we already identify if there are any cyclic
dependencies that prevents vectorization.

The vectorizer is taught to extract the last element from the vectorized
phi and update the scalar loop exit block phi to contain this extracted
element from the vector loop.

This patch can be extended to vectorize loops where instructions other
than phis have outside uses.

Reviewers: Ayal, mkuper, mssimpso, efriedma

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50579

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339703 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-14 18:22:19 +00:00

268 lines
8.3 KiB
LLVM

; RUN: opt -S -loop-vectorize -force-vector-interleave=1 -force-vector-width=2 < %s 2>&1 | FileCheck %s
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S128"
@f = common global i32 0, align 4
@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
@c = common global i32 0, align 4
@a = common global i32 0, align 4
@b = common global i32 0, align 4
@e = common global i32 0, align 4
; It has a value that is used outside of the loop
; and is not a recognized reduction variable "tmp17".
; However, tmp17 is a non-header phi which is an allowed exit.
; CHECK-LABEL: @test1(
; CHECK: %vec.ind = phi <2 x i32>
; CHECK: [[CMP:%[a-zA-Z0-9.]+]] = icmp sgt <2 x i32> %vec.ind, <i32 10, i32 10>
; CHECK: %predphi = select <2 x i1> [[CMP]], <2 x i32> <i32 1, i32 1>, <2 x i32> zeroinitializer
; CHECK-LABEL: middle.block:
; CHECK: [[E1:%[a-zA-Z0-9.]+]] = extractelement <2 x i32> %predphi, i32 1
; CHECK-LABEL: f1.exit.loopexit:
; CHECK: %.lcssa = phi i32 [ %tmp17, %bb16 ], [ [[E1]], %middle.block ]
define i32 @test1() {
bb:
%b.promoted = load i32, i32* @b, align 4
br label %.lr.ph.i
.lr.ph.i:
%tmp8 = phi i32 [ %tmp18, %bb16 ], [ %b.promoted, %bb ]
%tmp2 = icmp sgt i32 %tmp8, 10
br i1 %tmp2, label %bb16, label %bb10
bb10:
br label %bb16
bb16:
%tmp17 = phi i32 [ 0, %bb10 ], [ 1, %.lr.ph.i ]
%tmp18 = add nsw i32 %tmp8, 1
%tmp19 = icmp slt i32 %tmp18, 4
br i1 %tmp19, label %.lr.ph.i, label %f1.exit.loopexit
f1.exit.loopexit:
%.lcssa = phi i32 [ %tmp17, %bb16 ]
ret i32 %.lcssa
}
; non-hdr phi depends on header phi.
; CHECK-LABEL: @test2(
; CHECK: %vec.ind = phi <2 x i32>
; CHECK: [[CMP:%[a-zA-Z0-9.]+]] = icmp sgt <2 x i32> %vec.ind, <i32 10, i32 10>
; CHECK: %predphi = select <2 x i1> [[CMP]], <2 x i32> <i32 1, i32 1>, <2 x i32> %vec.ind
; CHECK-LABEL: middle.block:
; CHECK: [[E1:%[a-zA-Z0-9.]+]] = extractelement <2 x i32> %predphi, i32 1
; CHECK-LABEL: f1.exit.loopexit:
; CHECK: %.lcssa = phi i32 [ %tmp17, %bb16 ], [ [[E1]], %middle.block ]
define i32 @test2() {
bb:
%b.promoted = load i32, i32* @b, align 4
br label %.lr.ph.i
.lr.ph.i:
%tmp8 = phi i32 [ %tmp18, %bb16 ], [ %b.promoted, %bb ]
%tmp2 = icmp sgt i32 %tmp8, 10
br i1 %tmp2, label %bb16, label %bb10
bb10:
br label %bb16
bb16:
%tmp17 = phi i32 [ %tmp8, %bb10 ], [ 1, %.lr.ph.i ]
%tmp18 = add nsw i32 %tmp8, 1
%tmp19 = icmp slt i32 %tmp18, 4
br i1 %tmp19, label %.lr.ph.i, label %f1.exit.loopexit
f1.exit.loopexit:
%.lcssa = phi i32 [ %tmp17, %bb16 ]
ret i32 %.lcssa
}
; more than 2 incoming values for tmp17 phi that is used outside loop.
; CHECK-LABEL: test3(
; CHECK-LABEL: vector.body:
; CHECK: %predphi = select <2 x i1> %{{.*}}, <2 x i32> <i32 1, i32 1>, <2 x i32> zeroinitializer
; CHECK: %predphi1 = select <2 x i1> %{{.*}}, <2 x i32> <i32 2, i32 2>, <2 x i32> %predphi
; CHECK-LABEL: middle.block:
; CHECK: [[E1:%[a-zA-Z0-9.]+]] = extractelement <2 x i32> %predphi1, i32 1
; CHECK-LABEL: f1.exit.loopexit:
; CHECK: phi i32 [ %tmp17, %bb16 ], [ [[E1]], %middle.block ]
define i32 @test3(i32 %N) {
bb:
%b.promoted = load i32, i32* @b, align 4
br label %.lr.ph.i
.lr.ph.i:
%tmp8 = phi i32 [ %tmp18, %bb16 ], [ %b.promoted, %bb ]
%tmp2 = icmp sgt i32 %tmp8, 10
br i1 %tmp2, label %bb16, label %bb10
bb10:
%cmp = icmp sgt i32 %tmp8, %N
br i1 %cmp, label %bb12, label %bb16
bb12:
br label %bb16
bb16:
%tmp17 = phi i32 [ 0, %bb10 ], [ 1, %.lr.ph.i ], [ 2, %bb12 ]
%tmp18 = add nsw i32 %tmp8, 1
%tmp19 = icmp slt i32 %tmp18, 4
br i1 %tmp19, label %.lr.ph.i, label %f1.exit.loopexit
f1.exit.loopexit:
%.lcssa = phi i32 [ %tmp17, %bb16 ]
ret i32 %.lcssa
}
; more than one incoming value for outside user: %.lcssa
; CHECK-LABEL: test4(
; CHECK-LABEL: vector.body:
; CHECK: %predphi = select <2 x i1>
; CHECK-LABEL: middle.block:
; CHECK: [[E1:%[a-zA-Z0-9.]+]] = extractelement <2 x i32> %predphi, i32 1
; CHECK-LABEL: f1.exit.loopexit.loopexit:
; CHECK: %tmp17.lcssa = phi i32 [ %tmp17, %bb16 ], [ [[E1]], %middle.block ]
; CHECK-NEXT: br label %f1.exit.loopexit
; CHECK-LABEL: f1.exit.loopexit:
; CHECK: %.lcssa = phi i32 [ 2, %bb ], [ %tmp17.lcssa, %f1.exit.loopexit.loopexit ]
define i32 @test4(i32 %N) {
bb:
%b.promoted = load i32, i32* @b, align 4
%icmp = icmp slt i32 %b.promoted, %N
br i1 %icmp, label %f1.exit.loopexit, label %.lr.ph.i
.lr.ph.i:
%tmp8 = phi i32 [ %tmp18, %bb16 ], [ %b.promoted, %bb ]
%tmp2 = icmp sgt i32 %tmp8, 10
br i1 %tmp2, label %bb16, label %bb10
bb10:
br label %bb16
bb16:
%tmp17 = phi i32 [ 0, %bb10 ], [ 1, %.lr.ph.i ]
%tmp18 = add nsw i32 %tmp8, 1
%tmp19 = icmp slt i32 %tmp18, 4
br i1 %tmp19, label %.lr.ph.i, label %f1.exit.loopexit
f1.exit.loopexit:
%.lcssa = phi i32 [ %tmp17, %bb16 ], [ 2, %bb ]
ret i32 %.lcssa
}
; non hdr phi that depends on reduction and is used outside the loop.
; reduction phis are only allowed to have bump or reduction operations as the inside user, so we should
; not vectorize this.
; CHECK-LABEL: reduction_sum(
; CHECK-NOT: <2 x i32>
define i32 @reduction_sum(i32 %n, i32* noalias nocapture %A, i32* noalias nocapture %B) nounwind uwtable readonly noinline ssp {
entry:
%c1 = icmp sgt i32 %n, 0
br i1 %c1, label %header, label %._crit_edge
header: ; preds = %0, %.lr.ph
%indvars.iv = phi i64 [ %indvars.iv.next, %bb16 ], [ 0, %entry ]
%sum.02 = phi i32 [ %c9, %bb16 ], [ 0, %entry ]
%c2 = getelementptr inbounds i32, i32* %A, i64 %indvars.iv
%c3 = load i32, i32* %c2, align 4
%c4 = getelementptr inbounds i32, i32* %B, i64 %indvars.iv
%c5 = load i32, i32* %c4, align 4
%tmp2 = icmp sgt i32 %sum.02, 10
br i1 %tmp2, label %bb16, label %bb10
bb10:
br label %bb16
bb16:
%tmp17 = phi i32 [ %sum.02, %bb10 ], [ 1, %header ]
%c6 = trunc i64 %indvars.iv to i32
%c7 = add i32 %sum.02, %c6
%c8 = add i32 %c7, %c3
%c9 = add i32 %c8, %c5
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %n
br i1 %exitcond, label %._crit_edge, label %header
._crit_edge: ; preds = %.lr.ph, %0
%sum.0.lcssa = phi i32 [ 0, %entry ], [ %c9, %bb16 ]
%nonhdr.lcssa = phi i32 [ 1, %entry], [ %tmp17, %bb16 ]
ret i32 %sum.0.lcssa
}
; invalid cyclic dependency with header phi iv, which prevents iv from being
; recognized as induction var.
; cannot vectorize.
; CHECK-LABEL: cyclic_dep_with_indvar(
; CHECK-NOT: <2 x i32>
define i32 @cyclic_dep_with_indvar() {
bb:
%b.promoted = load i32, i32* @b, align 4
br label %.lr.ph.i
.lr.ph.i:
%iv = phi i32 [ %ivnext, %bb16 ], [ %b.promoted, %bb ]
%tmp2 = icmp sgt i32 %iv, 10
br i1 %tmp2, label %bb16, label %bb10
bb10:
br label %bb16
bb16:
%tmp17 = phi i32 [ 0, %bb10 ], [ %iv, %.lr.ph.i ]
%ivnext = add nsw i32 %tmp17, 1
%tmp19 = icmp slt i32 %ivnext, 4
br i1 %tmp19, label %.lr.ph.i, label %f1.exit.loopexit
f1.exit.loopexit:
%.lcssa = phi i32 [ %tmp17, %bb16 ]
ret i32 %.lcssa
}
; non-reduction phi 'tmp17' used outside loop has cyclic dependence with %x.05 phi
; cannot vectorize.
; CHECK-LABEL: not_valid_reduction(
; CHECK-NOT: <2 x i32>
define i32 @not_valid_reduction(i32 %n, i32* noalias nocapture %A) nounwind uwtable readonly {
entry:
%cmp4 = icmp sgt i32 %n, 0
br i1 %cmp4, label %for.body, label %for.end
for.body: ; preds = %entry, %for.body
%indvars.iv = phi i64 [ %indvars.iv.next, %latch ], [ 0, %entry ]
%x.05 = phi i32 [ %tmp17, %latch ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32, i32* %A, i64 %indvars.iv
%tmp0 = load i32, i32* %arrayidx, align 4
%tmp2 = icmp sgt i64 %indvars.iv, 10
%sub = sub nsw i32 %x.05, %tmp0
br i1 %tmp2, label %bb16, label %bb10
bb10:
br label %bb16
bb16:
%tmp17 = phi i32 [ 1, %bb10 ], [ %sub, %for.body ]
br label %latch
latch:
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %n
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body, %entry
%x.0.lcssa = phi i32 [ 0, %entry ], [ %tmp17 , %latch ]
ret i32 %x.0.lcssa
}