778b455dd6
Adds new optimization remarks when vectorization fails. More specifically, new remarks are added for following 4 cases: - Backward dependency - Backward dependency that prevents Store-to-load forwarding - Forward dependency that prevents Store-to-load forwarding - Unknown dependency It is important to note that only one of the sources of failures (to vectorize) is reported by the remarks. This source of failure may not be first in program order. A regression test has been added to test the following cases: a) Loop can be vectorized: No optimization remark is emitted b) Loop can not be vectorized: In this case an optimization remark will be emitted for one source of failure. Reviewed By: sdesmalen, david-arm Differential Revision: https://reviews.llvm.org/D108371
74 lines
3.6 KiB
LLVM
74 lines
3.6 KiB
LLVM
; RUN: opt -loop-vectorize -force-vector-width=2 -pass-remarks-analysis=loop-vectorize < %s 2>&1 | FileCheck %s
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; ModuleID = '/tmp/kk.c'
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source_filename = "/tmp/kk.c"
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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; 1 void success (char *A, char *B, char *C, char *D, char *E, int N) {
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; 2 for(int i = 0; i < N; i++) {
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; 3 A[i + 1] = A[i] + B[i];
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; 4 C[i] = D[i] * E[i];
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; 5 }
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; 6 }
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; CHECK: remark: /tmp/kk.c:3:14: loop not vectorized: unsafe dependent memory operations in loop. Use #pragma loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
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define void @success(i8* nocapture %A, i8* nocapture readonly %B, i8* nocapture %C, i8* nocapture readonly %D, i8* nocapture readonly %E, i32 %N) !dbg !6 {
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entry:
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%cmp28 = icmp sgt i32 %N, 0, !dbg !8
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br i1 %cmp28, label %for.body, label %for.cond.cleanup, !dbg !9
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for.body: ; preds = %entry, %for.body
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%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
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%arrayidx = getelementptr inbounds i8, i8* %A, i64 %indvars.iv, !dbg !11
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%0 = load i8, i8* %arrayidx, align 1, !dbg !11, !tbaa !12
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%arrayidx2 = getelementptr inbounds i8, i8* %B, i64 %indvars.iv, !dbg !15
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%1 = load i8, i8* %arrayidx2, align 1, !dbg !15, !tbaa !12
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%add = add i8 %1, %0, !dbg !16
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !9
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%arrayidx7 = getelementptr inbounds i8, i8* %A, i64 %indvars.iv.next, !dbg !17
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store i8 %add, i8* %arrayidx7, align 1, !dbg !18, !tbaa !12
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%arrayidx9 = getelementptr inbounds i8, i8* %D, i64 %indvars.iv, !dbg !19
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%2 = load i8, i8* %arrayidx9, align 1, !dbg !19, !tbaa !12
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%arrayidx12 = getelementptr inbounds i8, i8* %E, i64 %indvars.iv, !dbg !20
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%3 = load i8, i8* %arrayidx12, align 1, !dbg !20, !tbaa !12
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%mul = mul i8 %3, %2, !dbg !21
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%arrayidx16 = getelementptr inbounds i8, i8* %C, i64 %indvars.iv, !dbg !22
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store i8 %mul, i8* %arrayidx16, align 1, !dbg !23, !tbaa !12
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !9
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%exitcond = icmp eq i32 %lftr.wideiv, %N, !dbg !9
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br i1 %exitcond, label %for.cond.cleanup, label %for.body, !dbg !9
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for.cond.cleanup: ; preds = %for.body, %entry
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ret void, !dbg !10
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}
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4}
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!llvm.ident = !{!5}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: NoDebug, enums: !2)
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!1 = !DIFile(filename: "/tmp/kk.c", directory: "/tmp")
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!2 = !{}
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!3 = !{i32 2, !"Debug Info Version", i32 3}
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!4 = !{i32 1, !"PIC Level", i32 2}
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!5 = !{!"clang version 3.9.0 "}
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!6 = distinct !DISubprogram(name: "success", scope: !1, file: !1, line: 1, type: !7, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, retainedNodes: !2)
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!7 = !DISubroutineType(types: !2)
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!8 = !DILocation(line: 2, column: 20, scope: !6)
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!9 = !DILocation(line: 2, column: 3, scope: !6)
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!10 = !DILocation(line: 6, column: 1, scope: !6)
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!11 = !DILocation(line: 3, column: 16, scope: !6)
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!12 = !{!13, !13, i64 0}
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!13 = !{!"omnipotent char", !14, i64 0}
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!14 = !{!"Simple C/C++ TBAA"}
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!15 = !DILocation(line: 3, column: 23, scope: !6)
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!16 = !DILocation(line: 3, column: 21, scope: !6)
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!17 = !DILocation(line: 3, column: 5, scope: !6)
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!18 = !DILocation(line: 3, column: 14, scope: !6)
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!19 = !DILocation(line: 4, column: 12, scope: !6)
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!20 = !DILocation(line: 4, column: 19, scope: !6)
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!21 = !DILocation(line: 4, column: 17, scope: !6)
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!22 = !DILocation(line: 4, column: 5, scope: !6)
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!23 = !DILocation(line: 4, column: 10, scope: !6)
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