[clang] [llvm] [DebugInfo] Use DW_op_bit_piece for structured bindings of bitfields (PR #85665)

[Adrian Prantl via cfe-commits]

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@@ -8,8 +8,8 @@ struct S0 {
 // CHECK-LABEL: define dso_local void @_Z3fS0v
 // CHECK:                        alloca %struct.S0, align 4
 // CHECK-NEXT:    [[TMP0:%.*]] = alloca %struct.S0, align 4
-// CHECK:         call void @llvm.dbg.declare(metadata ptr [[TMP0]], metadata [[S0_A:![0-9]+]], metadata !DIExpression())
-// CHECK-NEXT:    call void @llvm.dbg.declare(metadata ptr [[TMP0]], metadata [[S0_B:![0-9]+]], metadata !DIExpression(DW_OP_plus_uconst, 2))
+// CHECK:         call void @llvm.dbg.declare(metadata ptr [[TMP0]], metadata [[S0_A:![0-9]+]], metadata !DIExpression(DW_OP_bit_piece, 16, 0))
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adrian-prantl wrote:

Regardless of which variant we choose, we probably need to add explicit support for it to SROA.cpp to make sure it gets translated correctly when the alloca gets split up again.

https://github.com/llvm/llvm-project/pull/85665