loop-unroll: teach remapInstruction to update dbg.value intrinsics.

Fixes PR35112.

https://bugs.llvm.org/show_bug.cgi?id=35112

llvm-svn: 317138

2 files changed, 90 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index ece98095690..2ed059b9178 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -68,9 +68,23 @@ static inline void remapInstruction(Instruction *I,
                                     ValueToValueMapTy &VMap) {
   for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) {
     Value *Op = I->getOperand(op);
+
+    // Unwrap arguments of dbg.value intrinsics.
+    bool Wrapped = false;
+    if (auto *V = dyn_cast<MetadataAsValue>(Op))
+      if (auto *Unwrapped = dyn_cast<ValueAsMetadata>(V->getMetadata())) {
+        Op = Unwrapped->getValue();
+        Wrapped = true;
+      }
+
+    auto wrap = [&](Value *V) {
+      auto &C = I->getContext();
+      return Wrapped ? MetadataAsValue::get(C, ValueAsMetadata::get(V)) : V;
+    };
+
     ValueToValueMapTy::iterator It = VMap.find(Op);
     if (It != VMap.end())
-      I->setOperand(op, It->second);
+      I->setOperand(op, wrap(It->second));
   }
 
   if (PHINode *PN = dyn_cast<PHINode>(I)) {
diff --git a/llvm/test/Transforms/LoopUnroll/debug-info.ll b/llvm/test/Transforms/LoopUnroll/debug-info.ll
new file mode 100644
index 00000000000..99fca012cab
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnroll/debug-info.ll
@@ -0,0 +1,75 @@
+; RUN: opt %s -S -o - -loop-unroll | FileCheck %s
+; generated at -O3 from:
+; void f() {
+;   for (int i = 1; i <=32; i <<=2 )
+;     bar(i>>1);
+; }
+source_filename = "/tmp/loop.c"
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.13.0"
+
+; Function Attrs: nounwind ssp uwtable
+define void @f() local_unnamed_addr #0 !dbg !8 {
+entry:
+  tail call void @llvm.dbg.value(metadata i32 1, metadata !12, metadata !DIExpression()), !dbg !15
+  br label %for.body, !dbg !16
+
+for.cond.cleanup:                                 ; preds = %for.body
+  ret void, !dbg !17
+
+for.body:                                         ; preds = %entry, %for.body
+  %i.04 = phi i32 [ 1, %entry ], [ %shl, %for.body ]
+  tail call void @llvm.dbg.value(metadata i32 %i.04, metadata !12, metadata !DIExpression()), !dbg !15
+  %shr = ashr i32 %i.04, 1, !dbg !18
+
+  ; The loop gets unrolled entirely.
+  ; CHECK: call void @llvm.dbg.value(metadata i32 1, metadata !12, metadata !DIExpression()), !dbg !15
+  ; CHECK: call void @llvm.dbg.value(metadata i32 4, metadata !12, metadata !DIExpression()), !dbg !15
+  ; CHECK: call void @llvm.dbg.value(metadata i32 16, metadata !12, metadata !DIExpression()), !dbg !15
+  ; CHECK: call void @llvm.dbg.value(metadata i32 64, metadata !12, metadata !DIExpression()), !dbg !15
+  
+  %call = tail call i32 (i32, ...) bitcast (i32 (...)* @bar to i32 (i32, ...)*)(i32 %shr) #3, !dbg !20
+  %shl = shl i32 %i.04, 2, !dbg !21
+  tail call void @llvm.dbg.value(metadata i32 %shl, metadata !12, metadata !DIExpression()), !dbg !15
+  %cmp = icmp slt i32 %shl, 33, !dbg !22
+  br i1 %cmp, label %for.body, label %for.cond.cleanup, !dbg !16, !llvm.loop !23
+}
+
+declare i32 @bar(...) local_unnamed_addr
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata) #2
+
+attributes #0 = { nounwind ssp uwtable }
+attributes #2 = { nounwind readnone speculatable }
+attributes #3 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0 (trunk 317113) (llvm/trunk 317122)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "/tmp/loop.c", directory: "/Data/llvm")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!7 = !{!"clang version 6.0.0 (trunk 317113) (llvm/trunk 317122)"}
+!8 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 1, type: !9, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !0, variables: !11)
+!9 = !DISubroutineType(types: !10)
+!10 = !{null}
+!11 = !{!12}
+!12 = !DILocalVariable(name: "i", scope: !13, file: !1, line: 2, type: !14)
+!13 = distinct !DILexicalBlock(scope: !8, file: !1, line: 2, column: 3)
+!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!15 = !DILocation(line: 2, column: 12, scope: !13)
+!16 = !DILocation(line: 2, column: 3, scope: !13)
+!17 = !DILocation(line: 4, column: 1, scope: !8)
+!18 = !DILocation(line: 3, column: 10, scope: !19)
+!19 = distinct !DILexicalBlock(scope: !13, file: !1, line: 2, column: 3)
+!20 = !DILocation(line: 3, column: 5, scope: !19)
+!21 = !DILocation(line: 2, column: 29, scope: !19)
+!22 = !DILocation(line: 2, column: 21, scope: !19)
+!23 = distinct !{!23, !16, !24}
+!24 = !DILocation(line: 3, column: 13, scope: !13)