[InstCombine][debuginfo] Update valueCoversEntireFragment for fixed size fragment and scalable value.

[fakepaper56]

Summary

Update valueCoversEntireFragment to handle new case and add regression test.

[sdesmalen]

llvm/test/Transforms/InstCombine/dbg-scalable-store-fixed-frag.ll

2

There are no CHECK-lines and the running opt on this file doesn't cause an assertion failure for me. What is this test supposed to verify?

[fakepaper56]

Update test case.

[fakepaper56]

llvm/test/Transforms/InstCombine/dbg-scalable-store-fixed-frag.ll

2

Sorry that I update the test. It should fail by assertion.

[sdesmalen]

llvm/lib/Transforms/Utils/Local.cpp

1497–1498

I'm not sure how valueCoversEntireFragment is used, but would it make more sense to write:

return TypeSize::isKnownGE(ValueSize, TypeSize::getFixed(*FragmentSize)

?

llvm/test/Transforms/InstCombine/dbg-scalable-store-fixed-frag.ll

2

Thanks, I can confirm the test now fails for me.

[fakepaper56]

Address sdesmalen comment and refine test cases.

[fakepaper56]

llvm/lib/Transforms/Utils/Local.cpp

1497–1498

Good point. Thank your reminder. I also add tests for converting gdb.declare to gdb.value.

llvm/test/Transforms/InstCombine/dbg-scalable-store-fixed-frag.ll

2

Thank you for your check.

[aprantl]

llvm/test/Transforms/InstCombine/dbg-scalable-store-fixed-frag.ll

26

This IR isn't well-formed and a future verifier might reject it. Can you created two distinct DISubprograms and local variables for each of the functions?

[fakepaper56]

Use distinct debug infromation for different items.

[fakepaper56]

llvm/test/Transforms/InstCombine/dbg-scalable-store-fixed-frag.ll

26

Thank your good point. I have fixed it.

[sdesmalen]

Seems fine to me, but please give @aprantl a chance to have another look at it as well before you land it.

[fakepaper56]

Rebase and ping @aprantl.

llvm/lib/Transforms/Utils/Local.cpp

 /// This is primarily intended as a helper for the different
 /// ConvertDebugDeclareToDebugValue functions. The dbg.declare that is converted
 /// describes an alloca'd variable, so we need to use the alloc size of the
 /// value when doing the comparison. E.g. an i1 value will be identified as
 /// covering an n-bit fragment, if the store size of i1 is at least n bits.
 static bool valueCoversEntireFragment(Type *ValTy, DbgVariableIntrinsic *DII) {
   const DataLayout &DL = DII->getModule()->getDataLayout();
   TypeSize ValueSize = DL.getTypeAllocSizeInBits(ValTy);
-  if (std::optional<uint64_t> FragmentSize = DII->getFragmentSizeInBits()) {
-    assert(!ValueSize.isScalable() &&
-           "Fragments don't work on scalable types.");
-    return ValueSize.getFixedValue() >= *FragmentSize;
-  }
+  if (std::optional<uint64_t> FragmentSize = DII->getFragmentSizeInBits())
+    return TypeSize::isKnownGE(ValueSize, TypeSize::getFixed(*FragmentSize));
+
   // We can't always calculate the size of the DI variable (e.g. if it is a
   // VLA). Try to use the size of the alloca that the dbg intrinsic describes
   // intead.
   if (DII->isAddressOfVariable()) {
     // DII should have exactly 1 location when it is an address.
     assert(DII->getNumVariableLocationOps() == 1 &&
            "address of variable must have exactly 1 location operand.");
     if (auto *AI =

llvm/test/Transforms/InstCombine/dbg-scalable-store-fixed-frag.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes='instcombine' -S | FileCheck %s
+
+define i32 @foo(<vscale x 2 x i32> %x) {
+; CHECK-LABEL: @foo(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ARR:%.*]] = alloca i32, align 8
+; CHECK-NEXT:    call void @llvm.dbg.value(metadata <vscale x 2 x i32> undef, metadata [[META8:![0-9]+]], metadata !DIExpression()), !dbg [[DBG14:![0-9]+]]
+; CHECK-NEXT:    store <vscale x 2 x i32> [[X:%.*]], ptr [[ARR]], align 8
+; CHECK-NEXT:    [[RES:%.*]] = load i32, ptr [[ARR]], align 8
+; CHECK-NEXT:    ret i32 [[RES]]
+;
+entry:
+  %arr = alloca i32, align 4
+  call void @llvm.dbg.declare(metadata ptr %arr, metadata !8, metadata !DIExpression()), !dbg !14
+  store <vscale x 2 x i32> %x, ptr %arr, align 4
+  %res = load i32, ptr %arr
+  ret i32 %res
+}
+
+define i32 @foo2(<vscale x 2 x i32> %x) {
+; CHECK-LABEL: @foo2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ARR:%.*]] = alloca [4 x i32], align 8
+; CHECK-NEXT:    call void @llvm.dbg.declare(metadata ptr [[ARR]], metadata [[META15:![0-9]+]], metadata !DIExpression()), !dbg [[DBG17:![0-9]+]]
+; CHECK-NEXT:    store <vscale x 2 x i32> [[X:%.*]], ptr [[ARR]], align 8
+; CHECK-NEXT:    [[RES:%.*]] = load i32, ptr [[ARR]], align 8
+; CHECK-NEXT:    ret i32 [[RES]]
+;
+entry:
+  %arr = alloca [4 x i32], align 4
+  call void @llvm.dbg.declare(metadata ptr %arr, metadata !15, metadata !DIExpression()), !dbg !17
+  store <vscale x 2 x i32> %x, ptr %arr, align 4
+  %res = load i32, ptr %arr
+  ret i32 %res
+}
+
+; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #0
+
+attributes #0 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6, !7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 17.0.0 ([e-mail]:llvm/llvm-project.git a489e11439e36c7e0ec83b28a6fb1596a5c21faa)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, retainedTypes: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "u.cpp", directory: "/path/to/test", checksumkind: CSK_MD5, checksum: "42f62c17fb0f0110f515890bc6d69cb5")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 5}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{i32 1, !"target-abi", !"lp64d"}
+!7 = !{i32 8, !"SmallDataLimit", i32 8}
+!8 = !DILocalVariable(name: "arr", scope: !9, file: !1, line: 3, type: !12)
+!9 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: !1, file: !1, line: 2, type: !10, scopeLine: 2, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!10 = !DISubroutineType(types: !11)
+!11 = !{null}
+!12 = !DICompositeType(tag: DW_TAG_array_type, baseType: !13, size: 128, elements: !2)
+!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!14 = !DILocation(line: 3, column: 7, scope: !9)
+!15 = !DILocalVariable(name: "arr", scope: !16, file: !1, line: 6, type: !12)
+!16 = distinct !DISubprogram(name: "foo2", linkageName: "foo2", scope: !1, file: !1, line: 5, type: !10, scopeLine: 5, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!17 = !DILocation(line: 6, column: 7, scope: !16)