[llvm] r268987 - [LV] Hint at the new loop distribution pragma in optimization remark
Adam Nemet via llvm-commits
llvm-commits at lists.llvm.org
Mon May 9 16:03:44 PDT 2016
Author: anemet
Date: Mon May 9 18:03:44 2016
New Revision: 268987
URL: http://llvm.org/viewvc/llvm-project?rev=268987&view=rev
Log:
[LV] Hint at the new loop distribution pragma in optimization remark
When we encounter unsafe memory dependencies, loop distribution could
help.
Even though, the diagnostics is in LAA, it's only currently emitted in
the vectorizer.
Added:
llvm/trunk/test/Transforms/LoopVectorize/unsafe-dep-remark.ll
Modified:
llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
Modified: llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp?rev=268987&r1=268986&r2=268987&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp Mon May 9 18:03:44 2016
@@ -1694,8 +1694,12 @@ void LoopAccessInfo::analyzeLoop(const V
<< (PtrRtChecking.Need ? "" : " don't")
<< " need runtime memory checks.\n");
else {
- emitAnalysis(LoopAccessReport() <<
- "unsafe dependent memory operations in loop");
+ emitAnalysis(
+ LoopAccessReport()
+ << "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");
DEBUG(dbgs() << "LAA: unsafe dependent memory operations in loop\n");
}
}
Added: llvm/trunk/test/Transforms/LoopVectorize/unsafe-dep-remark.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/unsafe-dep-remark.ll?rev=268987&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/unsafe-dep-remark.ll (added)
+++ llvm/trunk/test/Transforms/LoopVectorize/unsafe-dep-remark.ll Mon May 9 18:03:44 2016
@@ -0,0 +1,74 @@
+; RUN: opt -loop-vectorize -force-vector-width=2 -pass-remarks-analysis=loop-vectorize < %s 2>&1 | FileCheck %s
+
+; ModuleID = '/tmp/kk.c'
+source_filename = "/tmp/kk.c"
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+; 1 void success (char *A, char *B, char *C, char *D, char *E, int N) {
+; 2 for(int i = 0; i < N; i++) {
+; 3 A[i + 1] = A[i] + B[i];
+; 4 C[i] = D[i] * E[i];
+; 5 }
+; 6 }
+
+; CHECK: remark: /tmp/kk.c:3:16: 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
+
+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 {
+entry:
+ %cmp28 = icmp sgt i32 %N, 0, !dbg !8
+ br i1 %cmp28, label %for.body, label %for.cond.cleanup, !dbg !9
+
+for.body: ; preds = %entry, %for.body
+ %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
+ %arrayidx = getelementptr inbounds i8, i8* %A, i64 %indvars.iv, !dbg !11
+ %0 = load i8, i8* %arrayidx, align 1, !dbg !11, !tbaa !12
+ %arrayidx2 = getelementptr inbounds i8, i8* %B, i64 %indvars.iv, !dbg !15
+ %1 = load i8, i8* %arrayidx2, align 1, !dbg !15, !tbaa !12
+ %add = add i8 %1, %0, !dbg !16
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !9
+ %arrayidx7 = getelementptr inbounds i8, i8* %A, i64 %indvars.iv.next, !dbg !17
+ store i8 %add, i8* %arrayidx7, align 1, !dbg !18, !tbaa !12
+ %arrayidx9 = getelementptr inbounds i8, i8* %D, i64 %indvars.iv, !dbg !19
+ %2 = load i8, i8* %arrayidx9, align 1, !dbg !19, !tbaa !12
+ %arrayidx12 = getelementptr inbounds i8, i8* %E, i64 %indvars.iv, !dbg !20
+ %3 = load i8, i8* %arrayidx12, align 1, !dbg !20, !tbaa !12
+ %mul = mul i8 %3, %2, !dbg !21
+ %arrayidx16 = getelementptr inbounds i8, i8* %C, i64 %indvars.iv, !dbg !22
+ store i8 %mul, i8* %arrayidx16, align 1, !dbg !23, !tbaa !12
+ %lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !9
+ %exitcond = icmp eq i32 %lftr.wideiv, %N, !dbg !9
+ br i1 %exitcond, label %for.cond.cleanup, label %for.body, !dbg !9
+
+for.cond.cleanup: ; preds = %for.body, %entry
+ ret void, !dbg !10
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+!llvm.ident = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: NoDebug, enums: !2)
+!1 = !DIFile(filename: "/tmp/kk.c", directory: "/tmp")
+!2 = !{}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"PIC Level", i32 2}
+!5 = !{!"clang version 3.9.0 "}
+!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, variables: !2)
+!7 = !DISubroutineType(types: !2)
+!8 = !DILocation(line: 2, column: 20, scope: !6)
+!9 = !DILocation(line: 2, column: 3, scope: !6)
+!10 = !DILocation(line: 6, column: 1, scope: !6)
+!11 = !DILocation(line: 3, column: 16, scope: !6)
+!12 = !{!13, !13, i64 0}
+!13 = !{!"omnipotent char", !14, i64 0}
+!14 = !{!"Simple C/C++ TBAA"}
+!15 = !DILocation(line: 3, column: 23, scope: !6)
+!16 = !DILocation(line: 3, column: 21, scope: !6)
+!17 = !DILocation(line: 3, column: 5, scope: !6)
+!18 = !DILocation(line: 3, column: 14, scope: !6)
+!19 = !DILocation(line: 4, column: 12, scope: !6)
+!20 = !DILocation(line: 4, column: 19, scope: !6)
+!21 = !DILocation(line: 4, column: 17, scope: !6)
+!22 = !DILocation(line: 4, column: 5, scope: !6)
+!23 = !DILocation(line: 4, column: 10, scope: !6)
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