[llvm] Handle #dbg_values in SROA. (PR #94070)

[Adrian Prantl via llvm-commits]

================
@@ -0,0 +1,57 @@
+; This test was obtained from swift source code and then automatically reducing it via Delta.
+; The swift source code was from the test test/DebugInfo/debug_scope_distinct.swift.
+
+; RUN: opt %s -S -p=sroa -o - | FileCheck %s
+
+; CHECK: [[SROA_5_SROA_21:%.*]] = alloca [7 x i8], align 8
+; CHECK-NEXT: tail call void @llvm.dbg.value(metadata ptr [[SROA_5_SROA_21]], metadata [[META59:![0-9]+]], metadata !DIExpression(DW_OP_deref, DW_OP_LLVM_fragment, 72, 56)), !dbg [[DBG72:![0-9]+]]
+
+; CHECK: tail call void @llvm.dbg.value(metadata ptr [[REG2:%[0-9]+]], metadata [[META54:![0-9]+]], metadata !DIExpression(DW_OP_deref)), !dbg [[DBG78:![0-9]+]]
+; CHECK-NEXT: tail call void @llvm.dbg.value(metadata ptr [[REG2:%[0-9]+]], metadata [[META56:![0-9]+]], metadata !DIExpression(DW_OP_deref)), !dbg [[DBG78]]
+; CHECK-NEXT: tail call void @llvm.dbg.value(metadata i64 0, metadata [[META57:![0-9]+]], metadata !DIExpression()), !dbg [[DBG78]]
+
+; CHECK: [[SROA_418_SROA_COPYLOAD:%.*]] = load i8, ptr [[SROA_418_0_U1_IDX:%.*]], align 8, !dbg [[DBG78]]
+; CHECK-NEXT: tail call void @llvm.dbg.value(metadata i8 [[SROA_418_SROA_COPYLOAD]], metadata [[META59]], metadata !DIExpression(DW_OP_deref, DW_OP_LLVM_fragment, 64, 8)), !dbg [[DBG72]]
+
+%T4main1TV13TangentVectorV = type <{ %T4main1UV13TangentVectorV, [7 x i8], %T4main1UV13TangentVectorV }>
+%T4main1UV13TangentVectorV = type <{ %T1M1SVySfG, [7 x i8], %T4main1VV13TangentVectorV }>
+%T1M1SVySfG = type <{ ptr, %Ts4Int8V }>
+%Ts4Int8V = type <{ i8 }>
+%T4main1VV13TangentVectorV = type <{ %T1M1SVySfG }>
+define hidden swiftcc void @"$s4main1TV13TangentVectorV1poiyA2E_AEtFZ"(ptr noalias nocapture sret(%T4main1TV13TangentVectorV) %0, ptr noalias nocapture dereferenceable(57) %1, ptr noalias nocapture dereferenceable(57) %2) #0 !dbg !44 {
+entry:
+  %3 = alloca %T4main1VV13TangentVectorV
+  %4 = alloca %T4main1UV13TangentVectorV
+  call void @llvm.dbg.value(metadata ptr %1, metadata !54, metadata !DIExpression(DW_OP_deref)), !dbg !61
+  call void @llvm.dbg.value(metadata ptr %2, metadata !56, metadata !DIExpression(DW_OP_deref)), !dbg !61
+  call void @llvm.dbg.value(metadata i64 0, metadata !57, metadata !DIExpression()), !dbg !61
+  %.u1 = getelementptr inbounds %T4main1TV13TangentVectorV, ptr %1, i32 0, i32 0
+  call void @llvm.memcpy.p0.p0.i64(ptr align 8 %4, ptr align 8 %.u1, i64 25, i1 false), !dbg !61
+  call void @llvm.dbg.value(metadata ptr %4, metadata !62, metadata !DIExpression(DW_OP_deref)), !dbg !75
+  %.s = getelementptr inbounds %T4main1UV13TangentVectorV, ptr %4, i32 0, i32 0
+  %.s.b = getelementptr inbounds %T1M1SVySfG, ptr %.s, i32 0, i32 1
+  %.s.b._value = getelementptr inbounds %Ts4Int8V, ptr %.s.b, i32 0, i32 0
+  %12 = load i8, ptr %.s.b._value
+  %.v = getelementptr inbounds %T4main1UV13TangentVectorV, ptr %4, i32 0, i32 2
+  call void @llvm.memcpy.p0.p0.i64(ptr align 8 %3, ptr align 8 %.v, i64 9, i1 false)
+  %.s4 = getelementptr inbounds %T4main1VV13TangentVectorV, ptr %3, i32 0, i32 0
+  %.s4.c = getelementptr inbounds %T1M1SVySfG, ptr %.s4, i32 0, i32 0
+  %18 = load ptr, ptr %.s4.c
+  ret void
+}
+!llvm.module.flags = !{ !7, !15}
+!7 = !{i32 2, !"Debug Info Version", i32 3}
+!15 = !{i32 1, !"Swift Minor Version", i8 0}
+!16 = distinct !DICompileUnit(language: DW_LANG_Swift, file: !17, sdk: "MacOSX14.4.sdk")
+!17 = !DIFile(filename: "/Users/emilpedersen/swift2/swift/test/IRGen/debug_scope_distinct.swift", directory: "/Users/emilpedersen/swift2")
+!44 = distinct !DISubprogram( unit: !16, retainedNodes: !53)
+!53 = !{}
+!54 = !DILocalVariable( scope: !44, flags: DIFlagArtificial)
----------------
adrian-prantl wrote:

These variables a strangely over-and under-reduced at the same time :-)
They don't have a name, but they are artificial?

https://github.com/llvm/llvm-project/pull/94070