shylie/llvm-project
1
0
Fork 0
Code Issues Pull Requests Actions 6 Packages Projects Releases Wiki Activity
llvm-project/llvm/test/Transforms/LoopVectorize/first-order-recurrence.ll
Anna Thomas 00dc1b74b7 [LV] Avoid vectorizing first order recurrence when phi uses are outside loop 
In the vectorization of first order recurrence, we vectorize such
that the last element in the vector will be the one extracted to pass into the
scalar remainder loop. However, this is not true when there is a phi (other
than the primary induction variable) is used outside the loop.
In such a case, we need the value from the second last iteration (i.e.
the phi value), not the last iteration (which would be the phi update).
I've added a test case for this. Also see PR32396.

A follow up patch would generate the correct code gen for such cases,
and turn this vectorization on.

Differential Revision: https://reviews.llvm.org/D31910

Reviewers: mssimpso
llvm-svn: 299985
2017-04-11 21:02:00 +00:00

374 lines
15 KiB
LLVM
Raw Blame History

; RUN: opt < %s -loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -dce -instcombine -S | FileCheck %s
; RUN: opt < %s -loop-vectorize -force-vector-width=4 -force-vector-interleave=2 -dce -instcombine -S | FileCheck %s --check-prefix=UNROLL
; RUN: opt < %s -loop-vectorize -force-vector-width=4 -force-vector-interleave=2 -S | FileCheck %s --check-prefix=UNROLL-NO-IC
target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
; void recurrence_1(int *a, int *b, int n) {
; for(int i = 0; i < n; i++)
; b[i] = a[i] + a[i - 1]
; }
;
; CHECK-LABEL: @recurrence_1(
; CHECK: vector.ph:
; CHECK: %vector.recur.init = insertelement <4 x i32> undef, i32 %pre_load, i32 3
; CHECK: vector.body:
; CHECK: %vector.recur = phi <4 x i32> [ %vector.recur.init, %vector.ph ], [ [[L1:%[a-zA-Z0-9.]+]], %vector.body ]
; CHECK: [[L1]] = load <4 x i32>
; CHECK: {{.*}} = shufflevector <4 x i32> %vector.recur, <4 x i32> [[L1]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; CHECK: middle.block:
; CHECK: %vector.recur.extract = extractelement <4 x i32> [[L1]], i32 3
; CHECK: scalar.ph:
; CHECK: %scalar.recur.init = phi i32 [ %vector.recur.extract, %middle.block ], [ %pre_load, %vector.memcheck ], [ %pre_load, %min.iters.checked ], [ %pre_load, %for.preheader ]
; CHECK: scalar.body:
; CHECK: %scalar.recur = phi i32 [ %scalar.recur.init, %scalar.ph ], [ {{.*}}, %scalar.body ]
;
; UNROLL-LABEL: @recurrence_1(
; UNROLL: vector.body:
; UNROLL: %vector.recur = phi <4 x i32> [ %vector.recur.init, %vector.ph ], [ [[L2:%[a-zA-Z0-9.]+]], %vector.body ]
; UNROLL: [[L1:%[a-zA-Z0-9.]+]] = load <4 x i32>
; UNROLL: [[L2]] = load <4 x i32>
; UNROLL: {{.*}} = shufflevector <4 x i32> %vector.recur, <4 x i32> [[L1]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; UNROLL: {{.*}} = shufflevector <4 x i32> [[L1]], <4 x i32> [[L2]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; UNROLL: middle.block:
; UNROLL: %vector.recur.extract = extractelement <4 x i32> [[L2]], i32 3
;
define void @recurrence_1(i32* nocapture readonly %a, i32* nocapture %b, i32 %n) {
entry:
br label %for.preheader
for.preheader:
%arrayidx.phi.trans.insert = getelementptr inbounds i32, i32* %a, i64 0
%pre_load = load i32, i32* %arrayidx.phi.trans.insert
br label %scalar.body
scalar.body:
%0 = phi i32 [ %pre_load, %for.preheader ], [ %1, %scalar.body ]
%indvars.iv = phi i64 [ 0, %for.preheader ], [ %indvars.iv.next, %scalar.body ]
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%arrayidx32 = getelementptr inbounds i32, i32* %a, i64 %indvars.iv.next
%1 = load i32, i32* %arrayidx32
%arrayidx34 = getelementptr inbounds i32, i32* %b, i64 %indvars.iv
%add35 = add i32 %1, %0
store i32 %add35, i32* %arrayidx34
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %n
br i1 %exitcond, label %for.exit, label %scalar.body
for.exit:
ret void
}
; int recurrence_2(int *a, int n) {
; int minmax;
; for (int i = 0; i < n; ++i)
; minmax = min(minmax, max(a[i] - a[i-1], 0));
; return minmax;
; }
;
; CHECK-LABEL: @recurrence_2(
; CHECK: vector.ph:
; CHECK: %vector.recur.init = insertelement <4 x i32> undef, i32 %.pre, i32 3
; CHECK: vector.body:
; CHECK: %vector.recur = phi <4 x i32> [ %vector.recur.init, %vector.ph ], [ [[L1:%[a-zA-Z0-9.]+]], %vector.body ]
; CHECK: [[L1]] = load <4 x i32>
; CHECK: {{.*}} = shufflevector <4 x i32> %vector.recur, <4 x i32> [[L1]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; CHECK: middle.block:
; CHECK: %vector.recur.extract = extractelement <4 x i32> [[L1]], i32 3
; CHECK: scalar.ph:
; CHECK: %scalar.recur.init = phi i32 [ %vector.recur.extract, %middle.block ], [ %.pre, %min.iters.checked ], [ %.pre, %for.preheader ]
; CHECK: scalar.body:
; CHECK: %scalar.recur = phi i32 [ %scalar.recur.init, %scalar.ph ], [ {{.*}}, %scalar.body ]
;
; UNROLL-LABEL: @recurrence_2(
; UNROLL: vector.body:
; UNROLL: %vector.recur = phi <4 x i32> [ %vector.recur.init, %vector.ph ], [ [[L2:%[a-zA-Z0-9.]+]], %vector.body ]
; UNROLL: [[L1:%[a-zA-Z0-9.]+]] = load <4 x i32>
; UNROLL: [[L2]] = load <4 x i32>
; UNROLL: {{.*}} = shufflevector <4 x i32> %vector.recur, <4 x i32> [[L1]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; UNROLL: {{.*}} = shufflevector <4 x i32> [[L1]], <4 x i32> [[L2]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; UNROLL: middle.block:
; UNROLL: %vector.recur.extract = extractelement <4 x i32> [[L2]], i32 3
;
define i32 @recurrence_2(i32* nocapture readonly %a, i32 %n) {
entry:
%cmp27 = icmp sgt i32 %n, 0
br i1 %cmp27, label %for.preheader, label %for.cond.cleanup
for.preheader:
%arrayidx2.phi.trans.insert = getelementptr inbounds i32, i32* %a, i64 -1
%.pre = load i32, i32* %arrayidx2.phi.trans.insert, align 4
br label %scalar.body
for.cond.cleanup.loopexit:
%minmax.0.cond.lcssa = phi i32 [ %minmax.0.cond, %scalar.body ]
br label %for.cond.cleanup
for.cond.cleanup:
%minmax.0.lcssa = phi i32 [ undef, %entry ], [ %minmax.0.cond.lcssa, %for.cond.cleanup.loopexit ]
ret i32 %minmax.0.lcssa
scalar.body:
%0 = phi i32 [ %.pre, %for.preheader ], [ %1, %scalar.body ]
%indvars.iv = phi i64 [ 0, %for.preheader ], [ %indvars.iv.next, %scalar.body ]
%minmax.028 = phi i32 [ undef, %for.preheader ], [ %minmax.0.cond, %scalar.body ]
%arrayidx = getelementptr inbounds i32, i32* %a, i64 %indvars.iv
%1 = load i32, i32* %arrayidx, align 4
%sub3 = sub nsw i32 %1, %0
%cmp4 = icmp sgt i32 %sub3, 0
%cond = select i1 %cmp4, i32 %sub3, i32 0
%cmp5 = icmp slt i32 %minmax.028, %cond
%minmax.0.cond = select i1 %cmp5, i32 %minmax.028, i32 %cond
%indvars.iv.next = add nuw nsw 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.cond.cleanup.loopexit, label %scalar.body
}
; void recurrence_3(short *a, double *b, int n, float f, short p) {
; b[0] = (double)a[0] - f * (double)p;
; for (int i = 1; i < n; i++)
; b[i] = (double)a[i] - f * (double)a[i - 1];
; }
;
; CHECK-LABEL: @recurrence_3(
; CHECK: vector.ph:
; CHECK: %vector.recur.init = insertelement <4 x i16> undef, i16 %0, i32 3
; CHECK: vector.body:
; CHECK: %vector.recur = phi <4 x i16> [ %vector.recur.init, %vector.ph ], [ [[L1:%[a-zA-Z0-9.]+]], %vector.body ]
; CHECK: [[L1]] = load <4 x i16>
; CHECK: {{.*}} = shufflevector <4 x i16> %vector.recur, <4 x i16> [[L1]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; CHECK: middle.block:
; CHECK: %vector.recur.extract = extractelement <4 x i16> [[L1]], i32 3
; CHECK: scalar.ph:
; CHECK: %scalar.recur.init = phi i16 [ %vector.recur.extract, %middle.block ], [ %0, %vector.memcheck ], [ %0, %min.iters.checked ], [ %0, %for.preheader ]
; CHECK: scalar.body:
; CHECK: %scalar.recur = phi i16 [ %scalar.recur.init, %scalar.ph ], [ {{.*}}, %scalar.body ]
;
; UNROLL-LABEL: @recurrence_3(
; UNROLL: vector.body:
; UNROLL: %vector.recur = phi <4 x i16> [ %vector.recur.init, %vector.ph ], [ [[L2:%[a-zA-Z0-9.]+]], %vector.body ]
; UNROLL: [[L1:%[a-zA-Z0-9.]+]] = load <4 x i16>
; UNROLL: [[L2]] = load <4 x i16>
; UNROLL: {{.*}} = shufflevector <4 x i16> %vector.recur, <4 x i16> [[L1]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; UNROLL: {{.*}} = shufflevector <4 x i16> [[L1]], <4 x i16> [[L2]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; UNROLL: middle.block:
; UNROLL: %vector.recur.extract = extractelement <4 x i16> [[L2]], i32 3
;
define void @recurrence_3(i16* nocapture readonly %a, double* nocapture %b, i32 %n, float %f, i16 %p) {
entry:
%0 = load i16, i16* %a, align 2
%conv = sitofp i16 %0 to double
%conv1 = fpext float %f to double
%conv2 = sitofp i16 %p to double
%mul = fmul fast double %conv2, %conv1
%sub = fsub fast double %conv, %mul
store double %sub, double* %b, align 8
%cmp25 = icmp sgt i32 %n, 1
br i1 %cmp25, label %for.preheader, label %for.end
for.preheader:
br label %scalar.body
scalar.body:
%1 = phi i16 [ %0, %for.preheader ], [ %2, %scalar.body ]
%advars.iv = phi i64 [ %advars.iv.next, %scalar.body ], [ 1, %for.preheader ]
%arrayidx5 = getelementptr inbounds i16, i16* %a, i64 %advars.iv
%2 = load i16, i16* %arrayidx5, align 2
%conv6 = sitofp i16 %2 to double
%conv11 = sitofp i16 %1 to double
%mul12 = fmul fast double %conv11, %conv1
%sub13 = fsub fast double %conv6, %mul12
%arrayidx15 = getelementptr inbounds double, double* %b, i64 %advars.iv
store double %sub13, double* %arrayidx15, align 8
%advars.iv.next = add nuw nsw i64 %advars.iv, 1
%lftr.wideiv = trunc i64 %advars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %n
br i1 %exitcond, label %for.end.loopexit, label %scalar.body
for.end.loopexit:
br label %for.end
for.end:
ret void
}
; void PR26734(short *a, int *b, int *c, int d, short *e) {
; for (; d != 21; d++) {
; *b &= *c;
; *e = *a - 6;
; *c = *e;
; }
; }
;
; CHECK-LABEL: @PR26734(
; CHECK-NOT: vector.ph:
; CHECK: }
;
define void @PR26734(i16* %a, i32* %b, i32* %c, i32 %d, i16* %e) {
entry:
%cmp4 = icmp eq i32 %d, 21
br i1 %cmp4, label %entry.for.end_crit_edge, label %for.body.lr.ph
entry.for.end_crit_edge:
%.pre = load i32, i32* %b, align 4
br label %for.end
for.body.lr.ph:
%0 = load i16, i16* %a, align 2
%sub = add i16 %0, -6
%conv2 = sext i16 %sub to i32
%c.promoted = load i32, i32* %c, align 4
%b.promoted = load i32, i32* %b, align 4
br label %for.body
for.body:
%inc7 = phi i32 [ %d, %for.body.lr.ph ], [ %inc, %for.body ]
%and6 = phi i32 [ %b.promoted, %for.body.lr.ph ], [ %and, %for.body ]
%conv25 = phi i32 [ %c.promoted, %for.body.lr.ph ], [ %conv2, %for.body ]
%and = and i32 %and6, %conv25
%inc = add nsw i32 %inc7, 1
%cmp = icmp eq i32 %inc, 21
br i1 %cmp, label %for.cond.for.end_crit_edge, label %for.body
for.cond.for.end_crit_edge:
%and.lcssa = phi i32 [ %and, %for.body ]
store i32 %conv2, i32* %c, align 4
store i32 %and.lcssa, i32* %b, align 4
store i16 %sub, i16* %e, align 2
br label %for.end
for.end:
ret void
}
; int PR27246() {
; unsigned int e, n;
; for (int i = 1; i < 49; ++i) {
; for (int k = i; k > 1; --k)
; e = k;
; n = e;
; }
; return n;
; }
;
; CHECK-LABEL: @PR27246(
; CHECK-NOT: vector.ph:
; CHECK: }
;
define i32 @PR27246() {
entry:
br label %for.cond1.preheader
for.cond1.preheader:
%i.016 = phi i32 [ 1, %entry ], [ %inc, %for.cond.cleanup3 ]
%e.015 = phi i32 [ undef, %entry ], [ %e.1.lcssa, %for.cond.cleanup3 ]
br label %for.cond1
for.cond.cleanup:
%e.1.lcssa.lcssa = phi i32 [ %e.1.lcssa, %for.cond.cleanup3 ]
ret i32 %e.1.lcssa.lcssa
for.cond1:
%e.1 = phi i32 [ %k.0, %for.cond1 ], [ %e.015, %for.cond1.preheader ]
%k.0 = phi i32 [ %dec, %for.cond1 ], [ %i.016, %for.cond1.preheader ]
%cmp2 = icmp sgt i32 %k.0, 1
%dec = add nsw i32 %k.0, -1
br i1 %cmp2, label %for.cond1, label %for.cond.cleanup3
for.cond.cleanup3:
%e.1.lcssa = phi i32 [ %e.1, %for.cond1 ]
%inc = add nuw nsw i32 %i.016, 1
%exitcond = icmp eq i32 %inc, 49
br i1 %exitcond, label %for.cond.cleanup, label %for.cond1.preheader
}
; UNROLL-NO-IC-LABEL: @PR30183(
; UNROLL-NO-IC: vector.ph:
; UNROLL-NO-IC-NEXT: [[VECTOR_RECUR_INIT:%.*]] = insertelement <4 x i32> undef, i32 [[PRE_LOAD:%.*]], i32 3
; UNROLL-NO-IC-NEXT: br label %vector.body
; UNROLL-NO-IC: vector.body:
; UNROLL-NO-IC-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %vector.ph ], [ [[INDEX_NEXT:%.*]], %vector.body ]
; UNROLL-NO-IC-NEXT: [[VECTOR_RECUR:%.*]] = phi <4 x i32> [ [[VECTOR_RECUR_INIT]], %vector.ph ], [ [[TMP42:%.*]], %vector.body ]
; UNROLL-NO-IC: [[TMP27:%.*]] = load i32, i32* {{.*}}
; UNROLL-NO-IC-NEXT: [[TMP28:%.*]] = load i32, i32* {{.*}}
; UNROLL-NO-IC-NEXT: [[TMP29:%.*]] = load i32, i32* {{.*}}
; UNROLL-NO-IC-NEXT: [[TMP30:%.*]] = load i32, i32* {{.*}}
; UNROLL-NO-IC-NEXT: [[TMP31:%.*]] = load i32, i32* {{.*}}
; UNROLL-NO-IC-NEXT: [[TMP32:%.*]] = load i32, i32* {{.*}}
; UNROLL-NO-IC-NEXT: [[TMP33:%.*]] = load i32, i32* {{.*}}
; UNROLL-NO-IC-NEXT: [[TMP34:%.*]] = load i32, i32* {{.*}}
; UNROLL-NO-IC-NEXT: [[TMP35:%.*]] = insertelement <4 x i32> undef, i32 [[TMP27]], i32 0
; UNROLL-NO-IC-NEXT: [[TMP36:%.*]] = insertelement <4 x i32> [[TMP35]], i32 [[TMP28]], i32 1
; UNROLL-NO-IC-NEXT: [[TMP37:%.*]] = insertelement <4 x i32> [[TMP36]], i32 [[TMP29]], i32 2
; UNROLL-NO-IC-NEXT: [[TMP38:%.*]] = insertelement <4 x i32> [[TMP37]], i32 [[TMP30]], i32 3
; UNROLL-NO-IC-NEXT: [[TMP39:%.*]] = insertelement <4 x i32> undef, i32 [[TMP31]], i32 0
; UNROLL-NO-IC-NEXT: [[TMP40:%.*]] = insertelement <4 x i32> [[TMP39]], i32 [[TMP32]], i32 1
; UNROLL-NO-IC-NEXT: [[TMP41:%.*]] = insertelement <4 x i32> [[TMP40]], i32 [[TMP33]], i32 2
; UNROLL-NO-IC-NEXT: [[TMP42]] = insertelement <4 x i32> [[TMP41]], i32 [[TMP34]], i32 3
; UNROLL-NO-IC-NEXT: [[TMP43:%.*]] = shufflevector <4 x i32> [[VECTOR_RECUR]], <4 x i32> [[TMP38]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; UNROLL-NO-IC-NEXT: [[TMP44:%.*]] = shufflevector <4 x i32> [[TMP38]], <4 x i32> [[TMP42]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; UNROLL-NO-IC-NEXT: [[INDEX_NEXT]] = add i64 [[INDEX]], 8
; UNROLL-NO-IC: br i1 {{.*}}, label %middle.block, label %vector.body
;
define void @PR30183(i32 %pre_load, i32* %a, i32* %b, i64 %n) {
entry:
br label %scalar.body
scalar.body:
%i = phi i64 [ 0, %entry ], [ %i.next, %scalar.body ]
%tmp0 = phi i32 [ %pre_load, %entry ], [ %tmp2, %scalar.body ]
%i.next = add nuw nsw i64 %i, 2
%tmp1 = getelementptr inbounds i32, i32* %a, i64 %i.next
%tmp2 = load i32, i32* %tmp1
%cond = icmp eq i64 %i.next,%n
br i1 %cond, label %for.end, label %scalar.body
for.end:
ret void
}
; UNROLL-NO-IC-LABEL: @constant_folded_previous_value(
; UNROLL-NO-IC: vector.body:
; UNROLL-NO-IC: [[VECTOR_RECUR:%.*]] = phi <4 x i64> [ <i64 undef, i64 undef, i64 undef, i64 0>, %vector.ph ], [ <i64 1, i64 1, i64 1, i64 1>, %vector.body ]
; UNROLL-NO-IC-NEXT: [[TMP0:%.*]] = shufflevector <4 x i64> [[VECTOR_RECUR]], <4 x i64> <i64 1, i64 1, i64 1, i64 1>, <4 x i32> <i32 3, i32 4, i32 5, i32 6>
; UNROLL-NO-IC: br i1 {{.*}}, label %middle.block, label %vector.body
;
define void @constant_folded_previous_value() {
entry:
br label %scalar.body
scalar.body:
%i = phi i64 [ 0, %entry ], [ %i.next, %scalar.body ]
%tmp2 = phi i64 [ 0, %entry ], [ %tmp3, %scalar.body ]
%tmp3 = add i64 0, 1
%i.next = add nuw nsw i64 %i, 1
%cond = icmp eq i64 %i.next, undef
br i1 %cond, label %for.end, label %scalar.body
for.end:
ret void
}
; FIXME: we can vectorize this first order recurrence, by generating two
; extracts - one for the phi `val.phi` and other for the phi update `addx`.
; val.phi at end of loop is 94 + x.
; CHECK-LABEL: extract_second_last_iteration
; CHECK-NOT: vector.body
define i32 @extract_second_last_iteration(i32* %cval, i32 %x) {
entry:
br label %for.body
for.body:
%inc.phi = phi i32 [ 0, %entry ], [ %inc, %for.body ]
%val.phi = phi i32 [ 0, %entry ], [ %addx, %for.body ]
%inc = add i32 %inc.phi, 1
%bc = zext i32 %inc.phi to i64
%addx = add i32 %inc.phi, %x
%cmp = icmp eq i32 %inc.phi, 95
br i1 %cmp, label %for.end, label %for.body
for.end:
ret i32 %val.phi
}
Reference in New Issue View Git Blame Copy Permalink