Do not add discriminator encoding for debug intrinsics.

[danielcdh]

Summary

There are certain requirements for debug location of debug intrinsics, e.g. the scope of the DILocalVariable should be the same as the scope of its debug location. As a result, we should not add discriminator encoding for debug intrinsics.

[aprantl]

Correct, discriminators don't make sense for debug intrinsics.

lib/Transforms/Utils/LoopUnroll.cpp

LoopUnrollResult llvm::UnrollLoop(
   // break this so that later we can re-simplify them.
   SmallSetVector<Loop *, 4> LoopsToSimplify;
   for (Loop *SubLoop : *L)
     LoopsToSimplify.insert(SubLoop);
 
   if (Header->getParent()->isDebugInfoForProfiling())
     for (BasicBlock *BB : L->getBlocks())
       for (Instruction &I : *BB)
+        if (!isa<DbgInfoIntrinsic>(&I))
           if (const DILocation *DIL = I.getDebugLoc())
             I.setDebugLoc(DIL->cloneWithDuplicationFactor(Count));
 
   for (unsigned It = 1; It != Count; ++It) {
     std::vector<BasicBlock*> NewBlocks;
     SmallDenseMap<const Loop *, Loop *, 4> NewLoops;
     NewLoops[L] = L;
 
     for (LoopBlocksDFS::RPOIterator BB = BlockBegin; BB != BlockEnd; ++BB) {
       ValueToValueMapTy VMap;

lib/Transforms/Vectorize/LoopVectorize.cpp

static Instruction *getDebugLocFromInstOrOperands(Instruction *I) {
   }
 
   return I;
 }
 
 void InnerLoopVectorizer::setDebugLocFromInst(IRBuilder<> &B, const Value *Ptr) {
   if (const Instruction *Inst = dyn_cast_or_null<Instruction>(Ptr)) {
     const DILocation *DIL = Inst->getDebugLoc();
-    if (DIL && Inst->getFunction()->isDebugInfoForProfiling())
+    if (DIL && Inst->getFunction()->isDebugInfoForProfiling() &&
+        !isa<DbgInfoIntrinsic>(Inst))
       B.SetCurrentDebugLocation(DIL->cloneWithDuplicationFactor(UF * VF));
     else
       B.SetCurrentDebugLocation(DIL);
   } else
     B.SetCurrentDebugLocation(DebugLoc());
 }
 
 #ifndef NDEBUG

test/Transforms/LoopVectorize/discriminator.ll

-; RUN: opt -S -loop-vectorize -force-vector-width=4 -force-vector-interleave=1 < %s | FileCheck --check-prefix=LOOPVEC_4_1 %s
-; RUN: opt -S -loop-vectorize -force-vector-width=2 -force-vector-interleave=3 < %s | FileCheck --check-prefix=LOOPVEC_2_3 %s
-; RUN: opt -S -loop-unroll  -unroll-count=5 < %s | FileCheck --check-prefix=LOOPUNROLL_5 %s
-; RUN: opt -S -loop-vectorize -force-vector-width=4 -force-vector-interleave=4 -loop-unroll -unroll-count=2 < %s | FileCheck --check-prefix=LOOPVEC_UNROLL %s
+; RUN: opt -S -loop-vectorize -force-vector-width=4 -force-vector-interleave=1 < %s | FileCheck --check-prefix=DBG_VALUE --check-prefix=LOOPVEC_4_1 %s
+; RUN: opt -S -loop-vectorize -force-vector-width=2 -force-vector-interleave=3 < %s | FileCheck --check-prefix=DBG_VALUE --check-prefix=LOOPVEC_2_3 %s
+; RUN: opt -S -loop-unroll  -unroll-count=5 < %s | FileCheck --check-prefix=DBG_VALUE --check-prefix=LOOPUNROLL_5 %s
+; RUN: opt -S -loop-vectorize -force-vector-width=4 -force-vector-interleave=4 -loop-unroll -unroll-count=2 < %s | FileCheck --check-prefix=DBG_VALUE --check-prefix=LOOPVEC_UNROLL %s
 
 ; Test if vectorization/unroll factor is recorded in discriminator.
 ;
 ; Original source code:
 ;  1 int *a;
 ;  2 int *b;
 ;  3 
 ;  4 void foo() {
 ;  5   for (int i = 0; i < 4096; i++)
 ;  6     a[i] += b[i];
 ;  7 }
 
 @a = local_unnamed_addr global i32* null, align 8
 @b = local_unnamed_addr global i32* null, align 8
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
 
 define void @_Z3foov() local_unnamed_addr #0 !dbg !6 {
   %1 = load i32*, i32** @b, align 8, !dbg !8, !tbaa !9
   %2 = load i32*, i32** @a, align 8, !dbg !13, !tbaa !9
   br label %3, !dbg !14
 
 ; <label>:3:                                      ; preds = %3, %0
   %indvars.iv = phi i64 [ 0, %0 ], [ %indvars.iv.next, %3 ]
   %4 = getelementptr inbounds i32, i32* %1, i64 %indvars.iv, !dbg !8
   %5 = load i32, i32* %4, align 4, !dbg !8, !tbaa !15
   %6 = getelementptr inbounds i32, i32* %2, i64 %indvars.iv, !dbg !13
   %7 = load i32, i32* %6, align 4, !dbg !17, !tbaa !15
   %8 = add nsw i32 %7, %5, !dbg !17
+;DBG_VALUE: call void @llvm.dbg.declare{{.*}}!dbg ![[DBG:[0-9]*]]
+  call void @llvm.dbg.declare(metadata i32 %8, metadata !22, metadata !DIExpression()), !dbg !17
   store i32 %8, i32* %6, align 4, !dbg !17, !tbaa !15
   %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1, !dbg !18
   %exitcond = icmp eq i64 %indvars.iv.next, 4096, !dbg !19
   br i1 %exitcond, label %9, label %3, !dbg !14, !llvm.loop !20
 
 ; <label>:9:                                      ; preds = %3
   ret void, !dbg !21
 }
 
+;DBG_VALUE: ![[TOP:[0-9]*]] = distinct !DISubprogram(name: "foo"
 ;LOOPVEC_4_1: discriminator: 17
 ;LOOPVEC_2_3: discriminator: 25
 ;LOOPUNROLL_5: discriminator: 21
 ; When unrolling after loop vectorize, both vec_body and remainder loop
 ; are unrolled.
 ;LOOPVEC_UNROLL: discriminator: 385
 ;LOOPVEC_UNROLL: discriminator: 9
+;DBG_VALUE: ![[DBG]] = {{.*}}, scope: ![[TOP]]
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!3, !4}
 
 !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, debugInfoForProfiling: true)
 !1 = !DIFile(filename: "a.cc", directory: "/")
 !3 = !{i32 2, !"Dwarf Version", i32 4}
 !4 = !{i32 2, !"Debug Info Version", i32 3}
 !6 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 4, unit: !0)
 !8 = !DILocation(line: 6, column: 13, scope: !6)
 !9 = !{!10, !10, i64 0}
 !10 = !{!"any pointer", !11, i64 0}
 !11 = !{!"omnipotent char", !12, i64 0}
 !12 = !{!"Simple C++ TBAA"}
 !13 = !DILocation(line: 6, column: 5, scope: !6)
 !14 = !DILocation(line: 5, column: 3, scope: !6)
 !15 = !{!16, !16, i64 0}
 !16 = !{!"int", !11, i64 0}
 !17 = !DILocation(line: 6, column: 10, scope: !6)
 !18 = !DILocation(line: 5, column: 30, scope: !6)
 !19 = !DILocation(line: 5, column: 21, scope: !6)
 !20 = distinct !{!20, !14}
 !21 = !DILocation(line: 7, column: 1, scope: !6)
+!22 = !DILocalVariable(name: "a", arg: 1, scope: !6, file: !1, line: 10)