[SelectionDAG] Do not salvage with vector node

[pengfei]

Summary

rG2eb7cbf987f21 added this code, which results in crash for vector
nodes. This patch solves it by skipping for the vector nodes.

Thanks Steve for helping reducing the test case.

Co-authored-by: Steve Merritt <[e-mail]>

[goldstein.w.n]

LGTM.

[aprantl]

Code change looks good, but I have some suggestions for the test.

llvm/test/DebugInfo/X86/dbg-value-no-crash.ll

3

Can you add a comment that this is about salvage debug info in SelectionDAG?

7

A test with no CHECK lines is hard to maintain, since it's unclear what is being tested for. Could you add some positive checks to the output? For example, you could compile with -stop-before=regalloc and then check for function start followed by a CHECK-NOT: DBG_VALUE

[pengfei]

In D152492#4408984, @aprantl wrote:

Code change looks good, but I have some suggestions for the test.

Done, thanks for the suggestions!

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

for (auto *DV : GetDbgValues(&N)) {
     if (DV->isInvalidated())
       continue;
     switch (N.getOpcode()) {
     default:
       break;
     case ISD::ADD:
       SDValue N0 = N.getOperand(0);
       SDValue N1 = N.getOperand(1);
-      if (!isConstantIntBuildVectorOrConstantInt(N0) &&
-          isConstantIntBuildVectorOrConstantInt(N1)) {
+      if (!isa<ConstantSDNode>(N0) && isa<ConstantSDNode>(N1)) {
         uint64_t Offset = N.getConstantOperandVal(1);
 
         // Rewrite an ADD constant node into a DIExpression. Since we are
         // performing arithmetic to compute the variable's *value* in the
         // DIExpression, we need to mark the expression with a
         // DW_OP_stack_value.
         auto *DIExpr = DV->getExpression();
         auto NewLocOps = DV->copyLocationOps();

llvm/test/DebugInfo/X86/dbg-value-no-crash.ll

+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -mattr=avx512bw,avx512vl -o - %s
+
+;; Check this won't result in crash.
+define <8 x i32> @foo(ptr %0, <8 x i32> %1, i8 %2, i8 %3) {
+  %5 = call <8 x i32> @llvm.smax.v8i32(<8 x i32> %1, <8 x i32> zeroinitializer)
+  %6 = add nsw <8 x i32> %1, <i32 -1, i32 -1, i32 -1, i32 -1, i32 -1, i32 -1, i32 -1, i32 -1>
+  call void @llvm.dbg.value(metadata <8 x i32> %6, metadata !4, metadata !DIExpression()), !dbg !15
+  %7 = bitcast i8 %2 to <8 x i1>
+  %8 = select <8 x i1> %7, <8 x i32> %6, <8 x i32> %5
+  %9 = call <8 x i32> @llvm.smax.v8i32(<8 x i32> %8, <8 x i32> zeroinitializer)
+  %10 = bitcast i8 %3 to <8 x i1>
+  %11 = select <8 x i1> %10, <8 x i32> %9, <8 x i32> <i32 255, i32 255, i32 255, i32 255, i32 255, i32 255, i32 255, i32 255>
+  ret <8 x i32> %11
+}
+
+declare <8 x i32> @llvm.smax.v8i32(<8 x i32>, <8 x i32>)
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 16.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2)
+!1 = !DIFile(filename: "a.cpp", directory: "/")
+!2 = !{}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !DILocalVariable(name: "a", arg: 2, scope: !5, file: !1, line: 12, type: !11)
+!5 = distinct !DISubprogram(name: "foo", scope: !6, file: !1, line: 12, type: !7, scopeLine: 12, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, declaration: !9, retainedNodes: !10)
+!6 = !DINamespace(name: "ns1", scope: null)
+!7 = !DISubroutineType(types: !8)
+!8 = !{null}
+!9 = !DISubprogram(name: "foo", scope: !6, file: !1, line: 132, type: !7, scopeLine: 12, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized)
+!10 = !{!4}
+!11 = !DICompositeType(tag: DW_TAG_array_type, baseType: !12, size: 256, flags: DIFlagVector, elements: !13)
+!12 = !DIBasicType(name: "long long", size: 64, encoding: DW_ATE_signed)
+!13 = !{!14}
+!14 = !DISubrange(count: 4)
+!15 = !DILocation(line: 0, scope: !5, inlinedAt: !16)
+!16 = !DILocation(line: 18, scope: !17)
+!17 = distinct !DISubprogram(name: "foo", scope: null, file: !1, type: !7, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)