[SLP]Do not salvage debug info from instructions, marked for deletion already.

If the instruction was processed already for the deletion, no need to
process it second time, it may cause compiler crash.

Author: alexey-bataev

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -2493,8 +2493,9 @@ class BoUpSLP {
       auto *I = cast<Instruction>(V);
       DeletedInstructions.insert(I);
     }
+    DenseSet<Value *> Processed;
     for (T *V : DeadVals) {
-      if (!V)
+      if (!V || !Processed.insert(V).second)
         continue;
       auto *I = cast<Instruction>(V);
       salvageDebugInfo(*I);

llvm/test/Transforms/SLPVectorizer/X86/debug-info-salvage.ll

@@ -0,0 +1,70 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S --passes=slp-vectorizer -mtriple=x86_64-unknown-linux -mattr=+avx2 < %s | FileCheck %s
+
+define void @test() {
+; CHECK-LABEL: define void @test(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br label %[[COND_END_I:.*]]
+; CHECK:       [[COND_END_I]]:
+; CHECK-NEXT:      #dbg_value(!DIArgList(i32 0, i32 undef), [[META3:![0-9]+]], !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_or, DW_OP_stack_value), [[META5:![0-9]+]])
+; CHECK-NEXT:    [[TMP0:%.*]] = call <2 x i32> @llvm.umin.v2i32(<2 x i32> zeroinitializer, <2 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP1:%.*]] = select <2 x i1> zeroinitializer, <2 x i32> zeroinitializer, <2 x i32> [[TMP0]]
+; CHECK-NEXT:    [[TMP2:%.*]] = shl <2 x i32> [[TMP1]], <i32 0, i32 16>
+; CHECK-NEXT:    [[TMP3:%.*]] = or <2 x i32> [[TMP2]], zeroinitializer
+; CHECK-NEXT:    [[TMP4:%.*]] = or <2 x i32> [[TMP3]], zeroinitializer
+; CHECK-NEXT:    [[TMP5:%.*]] = or <2 x i32> [[TMP4]], zeroinitializer
+; CHECK-NEXT:    store <2 x i32> [[TMP5]], ptr null, align 4
+; CHECK-NEXT:    ret void
+;
+entry:
+  %arrayidx51.1.i = getelementptr i8, ptr null, i64 4
+  %retval.sroa.3.0.insert.ext.i.i = zext i8 0 to i32
+  %retval.sroa.2.0.insert.ext.i.i = zext i8 0 to i32
+  br label %cond.end.i
+
+cond.end.i:
+  %add46.i30 = or i32 0, %retval.sroa.2.0.insert.ext.i.i
+  %add49.i = or i32 0, %retval.sroa.3.0.insert.ext.i.i
+  #dbg_value(i32 %add49.i, !8, !DIExpression(), !16)
+  %0 = tail call i32 @llvm.umin.i32(i32 %add46.i30, i32 0)
+  %cmp.i14.i.i.i = icmp slt i32 %add49.i, 0
+  %block_color.sroa.7.0.insert.ext.i = select i1 %cmp.i14.i.i.i, i32 0, i32 0
+  %block_color.sroa.7.0.insert.shift.i = shl i32 %block_color.sroa.7.0.insert.ext.i, 16
+  %block_color.sroa.5.0.insert.ext.i = select i1 false, i32 0, i32 %0
+  %block_color.sroa.5.0.insert.shift.i = shl i32 %block_color.sroa.5.0.insert.ext.i, 0
+  %block_color.sroa.7.0.insert.insert.i = or i32 %block_color.sroa.7.0.insert.shift.i, %block_color.sroa.5.0.insert.shift.i
+  %block_color.sroa.5.0.insert.insert.i = or i32 %block_color.sroa.7.0.insert.insert.i, 0
+  %block_color.sroa.0.0.insert.insert.i = or i32 %block_color.sroa.5.0.insert.insert.i, 0
+  store i32 %block_color.sroa.0.0.insert.insert.i, ptr null, align 4
+  %add46.1.i = or i32 0, %retval.sroa.2.0.insert.ext.i.i
+  %add49.1.i = or i32 0, %retval.sroa.3.0.insert.ext.i.i
+  %cmp.i11.i.i.1.i = icmp slt i32 %add46.1.i, 0
+  %1 = tail call i32 @llvm.umin.i32(i32 %add49.1.i, i32 0)
+  %block_color.sroa.7.0.insert.ext.1.i = select i1 false, i32 0, i32 %1
+  %block_color.sroa.7.0.insert.shift.1.i = shl i32 %block_color.sroa.7.0.insert.ext.1.i, 16
+  %block_color.sroa.5.0.insert.ext.1.i = select i1 %cmp.i11.i.i.1.i, i32 0, i32 0
+  %block_color.sroa.5.0.insert.shift.1.i = shl i32 %block_color.sroa.5.0.insert.ext.1.i, 0
+  %block_color.sroa.7.0.insert.insert.1.i = or i32 %block_color.sroa.7.0.insert.shift.1.i, %block_color.sroa.5.0.insert.shift.1.i
+  %block_color.sroa.5.0.insert.insert.1.i = or i32 %block_color.sroa.7.0.insert.insert.1.i, 0
+  %block_color.sroa.0.0.insert.insert.1.i = or i32 %block_color.sroa.5.0.insert.insert.1.i, 0
+  store i32 %block_color.sroa.0.0.insert.insert.1.i, ptr %arrayidx51.1.i, align 4
+  ret void
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1)
+!1 = !DIFile(filename: "q.cpp", directory: "/tmp")
+!7 = !{i32 2, !"Debug Info Version", i32 3}
+!8 = !DILocalVariable(name: "sb", arg: 4, scope: !9)
+!9 = distinct !DISubprogram(name: "color_rgba", unit: !0)
+!16 = !DILocation(scope: !9)
+;.
+; CHECK: [[META0:![0-9]+]] = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: [[META1:![0-9]+]], isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug)
+; CHECK: [[META1]] = !DIFile(filename: "q.cpp", directory: {{.*}})
+; CHECK: [[META3]] = !DILocalVariable(name: "sb", arg: 4, scope: [[META4:![0-9]+]])
+; CHECK: [[META4]] = distinct !DISubprogram(name: "color_rgba", scope: null, spFlags: DISPFlagDefinition, unit: [[META0]])
+; CHECK: [[META5]] = !DILocation(line: 0, scope: [[META4]])
+;.