[MemorySSA] Update MemorySSA when removing debug.value calls.

llvm-svn: 371084

Author: alinas

llvm/lib/Transforms/Utils/BasicBlockUtils.cpp

@@ -250,8 +250,10 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DomTreeUpdater *DTU,
       llvm::findDbgValues(DbgValues, Incoming);
       for (auto &DVI : DbgValues) {
         auto R = DbgValueSet.insert({DVI->getVariable(), DVI->getExpression()});
-        if (!R.second)
+        if (!R.second) {
+          MSSAU->removeMemoryAccess(DVI);
           DVI->eraseFromParent();
+        }
       }
     }
   }

llvm/test/Analysis/MemorySSA/debugvalue.ll

@@ -0,0 +1,44 @@
+; RUN: opt -disable-basicaa -loop-rotate -enable-mssa-loop-dependency -verify-memoryssa -S %s | FileCheck %s
+; REQUIRES: asserts
+
+; CHECK-LABEL: @f_w4_i2
+define void @f_w4_i2() {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.body, %entry
+  %i.0 = phi i16 [ 0, %entry ], [ %inc, %for.body ]
+  call void @llvm.dbg.value(metadata i16 %i.0, metadata !32, metadata !DIExpression()), !dbg !31
+  br i1 undef, label %for.body, label %for.cond.cleanup
+
+for.cond.cleanup:                                 ; preds = %for.cond
+  ret void
+
+for.body:                                         ; preds = %for.cond
+  store i32 undef, i32* undef, align 1
+  %inc = add i16 %i.0, 1
+  call void @llvm.dbg.value(metadata i16 %inc, metadata !32, metadata !DIExpression()), !dbg !31
+  br label %for.cond
+}
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.value(metadata, metadata, metadata) #1
+
+attributes #1 = { nounwind readnone speculatable willreturn }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!14}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0s", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+!1 = !DIFile(filename: "vec.c", directory: "test")
+!2 = !{}
+!3 = !{!4}
+!4 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
+!14 = !{i32 2, !"Debug Info Version", i32 3}
+!15 = distinct !DISubprogram(name: "f_w4_i2", scope: !1, file: !1, line: 36, type: !16, scopeLine: 38, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !23)
+!16 = !DISubroutineType(types: !17)
+!17 = !{null}
+!23 = !{}
+!30 = distinct !DILexicalBlock(scope: !15, file: !1, line: 43, column: 5)
+!31 = !DILocation(line: 0, scope: !30)
+!32 = !DILocalVariable(name: "i", scope: !30, file: !1, line: 43, type: !4)