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llvm-project/llvm/test/Transforms/LoopVectorize/X86/unroll-small-loops.ll
Nilanjana Basu c1c5b854ad
[LV] Remove loop trip count threshold for deciding whether to interleave a loop (#67725) 
A set of microbenchmarks (https://github.com/llvm/llvm-test-suite/pull/26) showed that loop interleaving can be beneficial for loops with low trip count as well. Loop interleaving count computation is updated accordingly in prior patches while this patch removes the loop trip count threshold for interleaving.
2024-02-05 17:23:58 -08:00

350 lines
12 KiB
LLVM
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; RUN: opt < %s -passes=loop-vectorize,dce -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -force-vector-width=4 -force-vector-interleave=0 -S \
; RUN: | FileCheck %s --check-prefix=CHECK-VECTOR
; RUN: opt < %s -passes=loop-vectorize,dce -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -force-vector-width=1 -force-vector-interleave=0 -S \
; RUN: | FileCheck %s --check-prefix=CHECK-SCALAR
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.8.0"
; We don't unroll this loop because it has a small constant trip count
; that is not profitable for generating a scalar epilogue
;
; CHECK-VECTOR-LABEL: @foo_trip_count_8(
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR-NOT: load <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR-NOT: store <4 x i32>
; CHECK-VECTOR: ret
;
; CHECK-SCALAR-LABEL: @foo_trip_count_8(
; CHECK-SCALAR: load i32, ptr
; CHECK-SCALAR-NOT: load i32, ptr
; CHECK-SCALAR: store i32
; CHECK-SCALAR-NOT: store i32
; CHECK-SCALAR: ret
define void @foo_trip_count_8(ptr nocapture %A) nounwind uwtable ssp {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%0 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
%1 = load i32, ptr %0, align 4
%2 = add nsw i32 %1, 6
store i32 %2, ptr %0, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 8
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}
; We should unroll this loop 4 times since TC being a multiple of VF means
; that the epilogue loop may not need to run, making it profitable for
; the vector loop to run even once
;
; CHECK-VECTOR-LABEL: @foo_trip_count_16(
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR-NOT: load <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR-NOT: store <4 x i32>
; CHECK-VECTOR: ret
;
; CHECK-SCALAR-LABEL: @foo_trip_count_16(
; CHECK-SCALAR: load i32, ptr
; CHECK-SCALAR-NOT: load i32, ptr
; CHECK-SCALAR: store i32
; CHECK-SCALAR-NOT: store i32
; CHECK-SCALAR: ret
define void @foo_trip_count_16(ptr nocapture %A) nounwind uwtable ssp {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%0 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
%1 = load i32, ptr %0, align 4
%2 = add nsw i32 %1, 6
store i32 %2, ptr %0, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 16
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}
; We should unroll this loop four times since unrolling it twice
; will produce the same epilogue TC of 1, making larger unroll count
; more profitable
;
; CHECK-VECTOR-LABEL: @foo_trip_count_17(
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR-NOT: load <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR-NOT: store <4 x i32>
; CHECK-VECTOR: ret
;
; CHECK-SCALAR-LABEL: @foo_trip_count_17(
; CHECK-SCALAR: load i32, ptr
; CHECK-SCALAR-NOT: load i32, ptr
; CHECK-SCALAR: store i32
; CHECK-SCALAR-NOT: store i32
; CHECK-SCALAR: ret
define void @foo_trip_count_17(ptr nocapture %A) nounwind uwtable ssp {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%0 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
%1 = load i32, ptr %0, align 4
%2 = add nsw i32 %1, 6
store i32 %2, ptr %0, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 17
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}
; We should unroll this loop twice since unrolling four times will
; create an epilogue loop of TC 8, while unrolling it twice will
; eliminate the epologue loop altogether
;
; CHECK-VECTOR-LABEL: @foo_trip_count_24(
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR-NOT: load <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR-NOT: store <4 x i32>
; CHECK-VECTOR: ret
;
; CHECK-SCALAR-LABEL: @foo_trip_count_24(
; CHECK-SCALAR: load i32, ptr
; CHECK-SCALAR-NOT: load i32, ptr
; CHECK-SCALAR: store i32
; CHECK-SCALAR-NOT: store i32
; CHECK-SCALAR: ret
define void @foo_trip_count_24(ptr nocapture %A) nounwind uwtable ssp {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%0 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
%1 = load i32, ptr %0, align 4
%2 = add nsw i32 %1, 6
store i32 %2, ptr %0, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 24
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}
; We should unroll this loop twice since TC not being a multiple of VF may require
; the epilogue loop to run, making it profitable when the vector loop runs
; at least twice.
;
; CHECK-VECTOR-LABEL: @foo_trip_count_25(
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR-NOT: load <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR-NOT: store <4 x i32>
; CHECK-VECTOR: ret
;
; CHECK-SCALAR-LABEL: @foo_trip_count_25(
; CHECK-SCALAR: load i32, ptr
; CHECK-SCALAR-NOT: load i32, ptr
; CHECK-SCALAR: store i32
; CHECK-SCALAR-NOT: store i32
; CHECK-SCALAR: ret
define void @foo_trip_count_25(ptr nocapture %A) nounwind uwtable ssp {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%0 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
%1 = load i32, ptr %0, align 4
%2 = add nsw i32 %1, 6
store i32 %2, ptr %0, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 25
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}
; We should unroll this loop 4 times since TC not being a multiple of VF may require
; the epilogue loop to run, making it profitable when the vector loop runs
; at least twice.
;
; CHECK-VECTOR-LABEL: @foo_trip_count_33(
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR-NOT: load <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR-NOT: store <4 x i32>
; CHECK-VECTOR: ret
;
; CHECK-SCALAR-LABEL: @foo_trip_count_33(
; CHECK-SCALAR: load i32, ptr
; CHECK-SCALAR-NOT: load i32, ptr
; CHECK-SCALAR: store i32
; CHECK-SCALAR-NOT: store i32
; CHECK-SCALAR: ret
define void @foo_trip_count_33(ptr nocapture %A) nounwind uwtable ssp {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%0 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
%1 = load i32, ptr %0, align 4
%2 = add nsw i32 %1, 6
store i32 %2, ptr %0, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 33
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}
; We should unroll this loop 4 times since TC not being a multiple of VF may require
; the epilogue loop to run, making it profitable when the vector loop runs
; at least twice. The IC is restricted to 4 since that is the maximum supported
; for the target.
;
; CHECK-VECTOR-LABEL: @foo_trip_count_101(
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR: load <4 x i32>
; CHECK-VECTOR-NOT: load <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR-NOT: store <4 x i32>
; CHECK-VECTOR: ret
;
; CHECK-SCALAR-LABEL: @foo_trip_count_101(
; CHECK-SCALAR: load i32, ptr
; CHECK-SCALAR-NOT: load i32, ptr
; CHECK-SCALAR: store i32
; CHECK-SCALAR-NOT: store i32
; CHECK-SCALAR: ret
define void @foo_trip_count_101(ptr nocapture %A) nounwind uwtable ssp {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%0 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
%1 = load i32, ptr %0, align 4
%2 = add nsw i32 %1, 6
store i32 %2, ptr %0, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, 101
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
}
; But this is a good small loop to unroll as we don't know of a bound on its
; trip count.
;
; CHECK-VECTOR-LABEL: @bar(
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: store <4 x i32>
; CHECK-VECTOR: ret
;
; For x86, loop unroll in loop vectorizer is disabled when VF==1.
;
; CHECK-SCALAR-LABEL: @bar(
; CHECK-SCALAR: store i32
; CHECK-SCALAR-NOT: store i32
; CHECK-SCALAR: ret
define void @bar(ptr nocapture %A, i32 %n) nounwind uwtable ssp {
%1 = icmp sgt i32 %n, 0
br i1 %1, label %.lr.ph, label %._crit_edge
.lr.ph: ; preds = %0, %.lr.ph
%indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %0 ]
%2 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
%3 = load i32, ptr %2, align 4
%4 = add nsw i32 %3, 6
store i32 %4, ptr %2, align 4
%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 %.lr.ph
._crit_edge: ; preds = %.lr.ph, %0
ret void
}
; Also unroll if we need a runtime check but it was going to be added for
; vectorization anyways.
; CHECK-VECTOR-LABEL: @runtime_chk(
; CHECK-VECTOR: store <4 x float>
; CHECK-VECTOR: store <4 x float>
;
; But not if the unrolling would introduce the runtime check.
; CHECK-SCALAR-LABEL: @runtime_chk(
; CHECK-SCALAR: store float
; CHECK-SCALAR-NOT: store float
define void @runtime_chk(ptr %A, ptr %B, float %N) {
entry:
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%arrayidx = getelementptr inbounds float, ptr %B, i64 %indvars.iv
%0 = load float, ptr %arrayidx, align 4
%mul = fmul float %0, %N
%arrayidx2 = getelementptr inbounds float, ptr %A, i64 %indvars.iv
store float %mul, ptr %arrayidx2, align 4
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%exitcond = icmp eq i64 %indvars.iv.next, 256
br i1 %exitcond, label %for.end, label %for.body
for.end:
ret void
}
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