[llvm] r267952 - [LoopDist] Emit optimization remarks (-Rpass*)

Adam Nemet via llvm-commits llvm-commits at lists.llvm.org
Thu Apr 28 16:08:33 PDT 2016


Author: anemet
Date: Thu Apr 28 18:08:32 2016
New Revision: 267952

URL: http://llvm.org/viewvc/llvm-project?rev=267952&view=rev
Log:
[LoopDist] Emit optimization remarks (-Rpass*)

I closely followed the precedents set by the vectorizer:

* With -Rpass-missed, the loop is reported with further details pointing
to -Rpass--analysis.

* -Rpass-analysis reports the details why distribution has failed.

* Regardless of -Rpass*, when distribution fails for a loop where
distribution was forced with the pragma, a warning is produced according
to -Wpass-failed.  In this case the analysis info is also printed even
without -Rpass-analysis.

Added:
    llvm/trunk/test/Transforms/LoopDistribute/diagnostics.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/LoopDistribute.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LoopDistribute.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopDistribute.cpp?rev=267952&r1=267951&r2=267952&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopDistribute.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopDistribute.cpp Thu Apr 28 18:08:32 2016
@@ -28,6 +28,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/LoopAccessAnalysis.h"
 #include "llvm/Analysis/LoopInfo.h"
+#include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
@@ -745,7 +746,31 @@ public:
 
   /// \brief Provide diagnostics then \return with false.
   bool fail(llvm::StringRef Message) {
+    Function *F = L->getHeader()->getParent();
+    LLVMContext &Ctx = F->getContext();
+    bool Forced = isForced().getValueOr(false);
+
     DEBUG(dbgs() << "Skipping; " << Message << "\n");
+
+    // With Rpass-missed report that distribution failed.
+    emitOptimizationRemarkMissed(
+        Ctx, LDIST_NAME, *F, L->getStartLoc(),
+        "loop not distributed: use -Rpass-analysis=loop-distribute for more "
+        "info");
+
+    // With Rpass-analysis report why.  This is on by default if distribution
+    // was requested explicitly.
+    emitOptimizationRemarkAnalysis(
+        Ctx, Forced ? DiagnosticInfo::AlwaysPrint : LDIST_NAME, *F,
+        L->getStartLoc(), Twine("loop not distributed: ") + Message);
+
+    // Also issue a warning if distribution was requested explicitly but it
+    // failed.
+    if (Forced)
+      Ctx.diagnose(DiagnosticInfoOptimizationFailure(
+          *F, L->getStartLoc(), "loop not disributed: failed "
+                                "explicitly specified loop distribution"));
+
     return false;
   }
 

Added: llvm/trunk/test/Transforms/LoopDistribute/diagnostics.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopDistribute/diagnostics.ll?rev=267952&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopDistribute/diagnostics.ll (added)
+++ llvm/trunk/test/Transforms/LoopDistribute/diagnostics.ll Thu Apr 28 18:08:32 2016
@@ -0,0 +1,118 @@
+; RUN: opt -loop-distribute -S < %s 2>&1 \
+; RUN:     | FileCheck %s --check-prefix=ALWAYS --check-prefix=NO_REMARKS
+; RUN: opt -loop-distribute -S -pass-remarks-missed=loop-distribute < %s 2>&1 \
+; RUN:     | FileCheck %s --check-prefix=ALWAYS --check-prefix=MISSED_REMARKS
+; RUN: opt -loop-distribute -S -pass-remarks-analysis=loop-distribute < %s 2>&1 \
+; RUN:     | FileCheck %s --check-prefix=ALWAYS --check-prefix=ANALYSIS_REMARKS
+
+; This is the input program:
+;
+;     1	void forced (char *A, char *B, char *C, int N) {
+;     2	#pragma clang loop distribute(enable)
+;     3	  for(int i = 0; i < N; i++) {
+;     4	    A[i] = B[i] * C[i];
+;     5	  }
+;     6	}
+;     7
+;     8	void not_forced (char *A, char *B, char *C, int N) {
+;     9	  for(int i = 0; i < N; i++) {
+;    10	    A[i] = B[i] * C[i];
+;    11	  }
+;    12	}
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+; MISSED_REMARKS: remark:  /tmp/t.c:3:3: loop not distributed: use -Rpass-analysis=loop-distribute for more info
+; ALWAYS:         remark: /tmp/t.c:3:3: loop not distributed: memory operations are safe for vectorization
+; ALWAYS:         warning: /tmp/t.c:3:3: loop not disributed: failed explicitly specified loop distribution
+
+define void @forced(i8* %A, i8* %B, i8* %C, i32 %N) !dbg !7 {
+entry:
+  %cmp12 = icmp sgt i32 %N, 0, !dbg !9
+  br i1 %cmp12, label %ph, label %for.cond.cleanup, !dbg !10
+
+ph:
+  br label %for.body
+
+for.body:
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %ph ]
+  %arrayidx = getelementptr inbounds i8, i8* %B, i64 %indvars.iv, !dbg !12
+  %0 = load i8, i8* %arrayidx, align 1, !dbg !12, !tbaa !13
+  %arrayidx2 = getelementptr inbounds i8, i8* %C, i64 %indvars.iv, !dbg !16
+  %1 = load i8, i8* %arrayidx2, align 1, !dbg !16, !tbaa !13
+  %mul = mul i8 %1, %0, !dbg !17
+  %arrayidx6 = getelementptr inbounds i8, i8* %A, i64 %indvars.iv, !dbg !18
+  store i8 %mul, i8* %arrayidx6, align 1, !dbg !19, !tbaa !13
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !10
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !10
+  %exitcond = icmp eq i32 %lftr.wideiv, %N, !dbg !10
+  br i1 %exitcond, label %for.cond.cleanup, label %for.body, !dbg !10, !llvm.loop !20
+
+for.cond.cleanup:
+  ret void, !dbg !11
+}
+
+; NO_REMARKS-NOT: remark: /tmp/t.c:9:3: loop not distributed: memory operations are safe for vectorization
+; MISSED_REMARKS: remark: /tmp/t.c:9:3: loop not distributed: use -Rpass-analysis=loop-distribute for more info
+; ANALYSIS_REMARKS: remark: /tmp/t.c:9:3: loop not distributed: memory operations are safe for vectorization
+; ALWAYS-NOT: warning: /tmp/t.c:9:3: loop not disributed: failed explicitly specified loop distribution
+
+define void @not_forced(i8* %A, i8* %B, i8* %C, i32 %N) !dbg !22 {
+entry:
+  %cmp12 = icmp sgt i32 %N, 0, !dbg !23
+  br i1 %cmp12, label %ph, label %for.cond.cleanup, !dbg !24
+
+ph:
+  br label %for.body
+
+for.body:
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %ph ]
+  %arrayidx = getelementptr inbounds i8, i8* %B, i64 %indvars.iv, !dbg !26
+  %0 = load i8, i8* %arrayidx, align 1, !dbg !26, !tbaa !13
+  %arrayidx2 = getelementptr inbounds i8, i8* %C, i64 %indvars.iv, !dbg !27
+  %1 = load i8, i8* %arrayidx2, align 1, !dbg !27, !tbaa !13
+  %mul = mul i8 %1, %0, !dbg !28
+  %arrayidx6 = getelementptr inbounds i8, i8* %A, i64 %indvars.iv, !dbg !29
+  store i8 %mul, i8* %arrayidx6, align 1, !dbg !30, !tbaa !13
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !24
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32, !dbg !24
+  %exitcond = icmp eq i32 %lftr.wideiv, %N, !dbg !24
+  br i1 %exitcond, label %for.cond.cleanup, label %for.body, !dbg !24
+
+for.cond.cleanup:
+  ret void, !dbg !25
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (trunk 267633) (llvm/trunk 267675)", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2)
+!1 = !DIFile(filename: "/tmp/t.c", directory: "/tmp")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 2}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!7 = distinct !DISubprogram(name: "forced", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
+!8 = !DISubroutineType(types: !2)
+!9 = !DILocation(line: 3, column: 20, scope: !7)
+!10 = !DILocation(line: 3, column: 3, scope: !7)
+!11 = !DILocation(line: 6, column: 1, scope: !7)
+!12 = !DILocation(line: 4, column: 12, scope: !7)
+!13 = !{!14, !14, i64 0}
+!14 = !{!"omnipotent char", !15, i64 0}
+!15 = !{!"Simple C/C++ TBAA"}
+!16 = !DILocation(line: 4, column: 19, scope: !7)
+!17 = !DILocation(line: 4, column: 17, scope: !7)
+!18 = !DILocation(line: 4, column: 5, scope: !7)
+!19 = !DILocation(line: 4, column: 10, scope: !7)
+!20 = distinct !{!20, !21}
+!21 = !{!"llvm.loop.distribute.enable", i1 true}
+!22 = distinct !DISubprogram(name: "not_forced", scope: !1, file: !1, line: 8, type: !8, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
+!23 = !DILocation(line: 9, column: 20, scope: !22)
+!24 = !DILocation(line: 9, column: 3, scope: !22)
+!25 = !DILocation(line: 12, column: 1, scope: !22)
+!26 = !DILocation(line: 10, column: 12, scope: !22)
+!27 = !DILocation(line: 10, column: 19, scope: !22)
+!28 = !DILocation(line: 10, column: 17, scope: !22)
+!29 = !DILocation(line: 10, column: 5, scope: !22)
+!30 = !DILocation(line: 10, column: 10, scope: !22)




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