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clang-p2996/llvm/test/Transforms/LoopVectorize/runtime-check.ll
Sjoerd Meijer 0fcb3afb40 [LV] Forced vectorization with runtime checks and OptForSize 
When vectorisation is forced with a pragma, we optimise for min size, and we
need to emit runtime memory checks, then allow this code growth and don't run
in an assert like we currently do.

This is the result of D65197 and D66803, and was a use-case not really
considered before. If this now happens, we emit an optimisation remark warning
about the code-size expansion, which can be avoided by not forcing
vectorisation or possibly source-code modifications.

Differential Revision: https://reviews.llvm.org/D67764

llvm-svn: 372694
2019-09-24 08:03:34 +00:00

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -dce -instcombine -S | FileCheck %s
; RUN: opt < %s -loop-vectorize -disable-basicaa -S -pass-remarks-analysis='loop-vectorize' 2>&1 | FileCheck %s -check-prefix=FORCED_OPTSIZE
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"
; Make sure we vectorize this loop:
; int foo(float *a, float *b, int n) {
; for (int i=0; i<n; ++i)
; a[i] = b[i] * 3;
; }
define i32 @foo(float* nocapture %a, float* nocapture %b, i32 %n) nounwind uwtable ssp {
; CHECK-LABEL: @foo(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CMP6:%.*]] = icmp sgt i32 [[N:%.*]], 0, !dbg !4
; CHECK-NEXT: br i1 [[CMP6]], label [[FOR_BODY_PREHEADER:%.*]], label [[FOR_END:%.*]], !dbg !4
; CHECK: for.body.preheader:
; CHECK-NEXT: [[TMP0:%.*]] = add i32 [[N]], -1, !dbg !9
; CHECK-NEXT: [[TMP1:%.*]] = zext i32 [[TMP0]] to i64, !dbg !9
; CHECK-NEXT: [[TMP2:%.*]] = add nuw nsw i64 [[TMP1]], 1, !dbg !9
; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP2]], 4, !dbg !9
; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_MEMCHECK:%.*]], !dbg !9
; CHECK: vector.memcheck:
; CHECK-NEXT: [[TMP3:%.*]] = add i32 [[N]], -1, !dbg !9
; CHECK-NEXT: [[TMP4:%.*]] = zext i32 [[TMP3]] to i64, !dbg !9
; CHECK-NEXT: [[TMP5:%.*]] = add nuw nsw i64 [[TMP4]], 1, !dbg !9
; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr float, float* [[A:%.*]], i64 [[TMP5]], !dbg !9
; CHECK-NEXT: [[SCEVGEP4:%.*]] = getelementptr float, float* [[B:%.*]], i64 [[TMP5]], !dbg !9
; CHECK-NEXT: [[BOUND0:%.*]] = icmp ugt float* [[SCEVGEP4]], [[A]], !dbg !9
; CHECK-NEXT: [[BOUND1:%.*]] = icmp ugt float* [[SCEVGEP]], [[B]], !dbg !9
; CHECK-NEXT: [[MEMCHECK_CONFLICT:%.*]] = and i1 [[BOUND0]], [[BOUND1]], !dbg !9
; CHECK-NEXT: br i1 [[MEMCHECK_CONFLICT]], label [[SCALAR_PH]], label [[VECTOR_PH:%.*]], !dbg !9
; CHECK: vector.ph:
; CHECK-NEXT: [[N_VEC:%.*]] = and i64 [[TMP2]], 8589934588, !dbg !9
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]], !dbg !9
; CHECK: vector.body:
; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ], !dbg !9
; CHECK-NEXT: [[TMP7:%.*]] = getelementptr inbounds float, float* [[B]], i64 [[INDEX]], !dbg !9
; CHECK-NEXT: [[TMP8:%.*]] = bitcast float* [[TMP7]] to <4 x float>*, !dbg !9
; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <4 x float>, <4 x float>* [[TMP8]], align 4, !dbg !9, !alias.scope !10
; CHECK-NEXT: [[TMP9:%.*]] = fmul <4 x float> [[WIDE_LOAD]], <float 3.000000e+00, float 3.000000e+00, float 3.000000e+00, float 3.000000e+00>, !dbg !9
; CHECK-NEXT: [[TMP10:%.*]] = getelementptr inbounds float, float* [[A]], i64 [[INDEX]], !dbg !9
; CHECK-NEXT: [[TMP11:%.*]] = bitcast float* [[TMP10]] to <4 x float>*, !dbg !9
; CHECK-NEXT: store <4 x float> [[TMP9]], <4 x float>* [[TMP11]], align 4, !dbg !9, !alias.scope !13, !noalias !10
; CHECK-NEXT: [[INDEX_NEXT]] = add i64 [[INDEX]], 4, !dbg !9
; CHECK-NEXT: [[TMP12:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]], !dbg !9
; CHECK-NEXT: br i1 [[TMP12]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !dbg !9, !llvm.loop !15
; CHECK: middle.block:
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[TMP2]], [[N_VEC]]
; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END_LOOPEXIT:%.*]], label [[SCALAR_PH]], !dbg !9
; CHECK: scalar.ph:
; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[FOR_BODY_PREHEADER]] ], [ 0, [[VECTOR_MEMCHECK]] ]
; CHECK-NEXT: br label [[FOR_BODY:%.*]], !dbg !9
; CHECK: for.body:
; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ [[INDVARS_IV_NEXT:%.*]], [[FOR_BODY]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], !dbg !9
; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds float, float* [[B]], i64 [[INDVARS_IV]], !dbg !9
; CHECK-NEXT: [[TMP13:%.*]] = load float, float* [[ARRAYIDX]], align 4, !dbg !9
; CHECK-NEXT: [[MUL:%.*]] = fmul float [[TMP13]], 3.000000e+00, !dbg !9
; CHECK-NEXT: [[ARRAYIDX2:%.*]] = getelementptr inbounds float, float* [[A]], i64 [[INDVARS_IV]], !dbg !9
; CHECK-NEXT: store float [[MUL]], float* [[ARRAYIDX2]], align 4, !dbg !9
; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1, !dbg !9
; CHECK-NEXT: [[LFTR_WIDEIV:%.*]] = trunc i64 [[INDVARS_IV_NEXT]] to i32, !dbg !9
; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i32 [[LFTR_WIDEIV]], [[N]], !dbg !9
; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_END_LOOPEXIT]], label [[FOR_BODY]], !dbg !9, !llvm.loop !17
; CHECK: for.end.loopexit:
; CHECK-NEXT: br label [[FOR_END]], !dbg !18
; CHECK: for.end:
; CHECK-NEXT: ret i32 undef, !dbg !18
;
entry:
%cmp6 = icmp sgt i32 %n, 0, !dbg !6
br i1 %cmp6, label %for.body, label %for.end, !dbg !6
for.body: ; preds = %entry, %for.body
%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ], !dbg !7
%arrayidx = getelementptr inbounds float, float* %b, i64 %indvars.iv, !dbg !7
%0 = load float, float* %arrayidx, align 4, !dbg !7
%mul = fmul float %0, 3.000000e+00, !dbg !7
%arrayidx2 = getelementptr inbounds float, float* %a, i64 %indvars.iv, !dbg !7
store float %mul, float* %arrayidx2, align 4, !dbg !7
%indvars.iv.next = add i64 %indvars.iv, 1, !dbg !7
%lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !7
%exitcond = icmp eq i32 %lftr.wideiv, %n, !dbg !7
br i1 %exitcond, label %for.end, label %for.body, !dbg !7
for.end: ; preds = %for.body, %entry
ret i32 undef, !dbg !8
}
; Make sure that we try to vectorize loops with a runtime check if the
; dependency check fails.
; CHECK-LABEL: test_runtime_check
; CHECK: <4 x float>
define void @test_runtime_check(float* %a, float %b, i64 %offset, i64 %offset2, i64 %n) {
entry:
br label %for.body
for.body:
%iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
%ind.sum = add i64 %iv, %offset
%arr.idx = getelementptr inbounds float, float* %a, i64 %ind.sum
%l1 = load float, float* %arr.idx, align 4
%ind.sum2 = add i64 %iv, %offset2
%arr.idx2 = getelementptr inbounds float, float* %a, i64 %ind.sum2
%l2 = load float, float* %arr.idx2, align 4
%m = fmul fast float %b, %l2
%ad = fadd fast float %l1, %m
store float %ad, float* %arr.idx, align 4
%iv.next = add nuw nsw i64 %iv, 1
%exitcond = icmp eq i64 %iv.next, %n
br i1 %exitcond, label %loopexit, label %for.body
loopexit:
ret void
}
; Check we do not generate runtime checks if we found a known dependence preventing
; vectorization. In this case, it is a read of c[i-1] followed by a write of c[i].
; The runtime checks would always fail.
; void test_runtime_check2(float *a, float b, unsigned offset, unsigned offset2, unsigned n, float *c) {
; for (unsigned i = 1; i < n; i++) {
; a[i+o1] += a[i+o2] + b;
; c[i] = c[i-1] + b;
; }
; }
;
; CHECK-LABEL: test_runtime_check2
; CHECK-NOT: <4 x float>
define void @test_runtime_check2(float* %a, float %b, i64 %offset, i64 %offset2, i64 %n, float* %c) {
entry:
br label %for.body
for.body:
%iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
%ind.sum = add i64 %iv, %offset
%arr.idx = getelementptr inbounds float, float* %a, i64 %ind.sum
%l1 = load float, float* %arr.idx, align 4
%ind.sum2 = add i64 %iv, %offset2
%arr.idx2 = getelementptr inbounds float, float* %a, i64 %ind.sum2
%l2 = load float, float* %arr.idx2, align 4
%m = fmul fast float %b, %l2
%ad = fadd fast float %l1, %m
store float %ad, float* %arr.idx, align 4
%c.ind = add i64 %iv, -1
%c.idx = getelementptr inbounds float, float* %c, i64 %c.ind
%lc = load float, float* %c.idx, align 4
%vc = fadd float %lc, 1.0
%c.idx2 = getelementptr inbounds float, float* %c, i64 %iv
store float %vc, float* %c.idx2
%iv.next = add nuw nsw i64 %iv, 1
%exitcond = icmp eq i64 %iv.next, %n
br i1 %exitcond, label %loopexit, label %for.body
loopexit:
ret void
}
; CHECK: !9 = !DILocation(line: 101, column: 1, scope: !{{.*}})
define dso_local void @forced_optsize(i64* noalias nocapture readonly %x_p, i64* noalias nocapture readonly %y_p, i64* noalias nocapture %z_p) minsize optsize {
;
; FORCED_OPTSIZE: remark: <unknown>:0:0: Code-size may be reduced by not forcing vectorization, or by source-code modifications eliminating the need for runtime checks (e.g., adding 'restrict').
; FORCED_OPTSIZE-LABEL: @forced_optsize(
; FORCED_OPTSIZE: vector.body:
;
entry:
br label %for.body
for.cond.cleanup:
ret void
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%arrayidx = getelementptr inbounds i64, i64* %x_p, i64 %indvars.iv
%0 = load i64, i64* %arrayidx, align 8
%arrayidx2 = getelementptr inbounds i64, i64* %y_p, i64 %indvars.iv
%1 = load i64, i64* %arrayidx2, align 8
%add = add nsw i64 %1, %0
%arrayidx4 = getelementptr inbounds i64, i64* %z_p, i64 %indvars.iv
store i64 %add, i64* %arrayidx4, align 8
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%exitcond = icmp eq i64 %indvars.iv.next, 128
br i1 %exitcond, label %for.cond.cleanup, label %for.body, !llvm.loop !12
}
!llvm.module.flags = !{!0, !1}
!llvm.dbg.cu = !{!9}
!0 = !{i32 2, !"Dwarf Version", i32 4}
!1 = !{i32 2, !"Debug Info Version", i32 3}
!2 = !{}
!3 = !DISubroutineType(types: !2)
!4 = !DIFile(filename: "test.cpp", directory: "/tmp")
!5 = distinct !DISubprogram(name: "foo", scope: !4, file: !4, line: 99, type: !3, isLocal: false, isDefinition: true, scopeLine: 100, flags: DIFlagPrototyped, isOptimized: false, unit: !9, retainedNodes: !2)
!6 = !DILocation(line: 100, column: 1, scope: !5)
!7 = !DILocation(line: 101, column: 1, scope: !5)
!8 = !DILocation(line: 102, column: 1, scope: !5)
!9 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang",
file: !10,
isOptimized: true, flags: "-O2",
splitDebugFilename: "abc.debug", emissionKind: 2)
!10 = !DIFile(filename: "path/to/file", directory: "/path/to/dir")
!11 = !{i32 2, !"Debug Info Version", i32 3}
!12 = distinct !{!12, !13, !14}
!13 = !{!"llvm.loop.vectorize.width", i32 2}
!14 = !{!"llvm.loop.vectorize.enable", i1 true}
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