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clang-p2996/llvm/test/Transforms/LoopVectorize/runtime-check.ll
Florian Hahn ef307b8c26 [LAA] Avoid generating RT checks for known deps preventing vectorization. 
If we found unsafe dependences other than 'unknown', we already know at
compile time that they are unsafe and the runtime checks should always
fail. So we can avoid generating them in those cases.

This should have no negative impact on performance as the runtime checks
that would be created previously should always fail. As a sanity check,
I measured the test-suite, spec2k and spec2k6 and there were no regressions.

Reviewers: Ayal, anemet, hsaito

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D55798

llvm-svn: 349794
2018-12-20 18:49:09 +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
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: [[TMP6:%.*]] = and i32 [[N]], 3, !dbg !9
; CHECK-NEXT: [[N_MOD_VF:%.*]] = zext i32 [[TMP6]] to i64, !dbg !9
; CHECK-NEXT: [[N_VEC:%.*]] = sub nsw i64 [[TMP2]], [[N_MOD_VF]], !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 i32 [[TMP6]], 0
; 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: !{{.*}})
!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}
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