Optimize integrate_generated_columns

[coolreader18]

Description of Changes

Not really important, just something I noticed could be cleaner.

Comparison for integrate_generated_columns for:

pub struct TestE {
    #[primary_key]
    #[auto_inc]
    id: u64,
    #[index(btree)]
    name: String,
}

LLVM IR before this change:

; <rust_wasm_test_module::_::test_e__TableHandle as spacetimedb::table::Table>::integrate_generated_columns
; Function Attrs: noinline nounwind nonlazybind
define internal fastcc void @"<rust_wasm_test_module::_::test_e__TableHandle as spacetimedb::table::Table>::integrate_generated_columns"(ptr noalias nocapture noundef align 8 dereferenceable(32) %_row, ptr noalias noundef nonnull readonly align 1 %0, i64 noundef %1) unnamed_addr #5 personality ptr @rust_eh_personality {
start:
  %self1.i.i = alloca %"core::result::Result<&[u8], spacetimedb_sats::buffer::DecodeError>", align 8
  %e.i = alloca %"spacetimedb_sats::buffer::DecodeError", align 8
  %_generated_cols = alloca { ptr, i64 }, align 8
  store ptr %0, ptr %_generated_cols, align 8
  %2 = getelementptr inbounds i8, ptr %_generated_cols, i64 8
  store i64 %1, ptr %2, align 8
  %3 = getelementptr inbounds i8, ptr %_row, i64 24
  %_8 = load i64, ptr %3, align 8, !noundef !27
  %4 = icmp eq i64 %_8, 0
  br i1 %4, label %bb1, label %bb4

bb1:                                              ; preds = %start
  call void @llvm.lifetime.start.p0(i64 40, ptr nonnull %self1.i.i), !noalias !2900
; call <&[u8] as spacetimedb_sats::buffer::BufReader>::get_slice
  call void @"<&[u8] as spacetimedb_sats::buffer::BufReader>::get_slice"(ptr noalias nocapture noundef nonnull sret([40 x i8]) align 8 dereferenceable(40) %self1.i.i, ptr noalias noundef nonnull align 8 dereferenceable(16) %_generated_cols, i64 noundef 8) #19, !noalias !2907
  %5 = load i64, ptr %self1.i.i, align 8, !range !2697, !noalias !2900, !noundef !27
  %6 = icmp eq i64 %5, -9223372036854775805
  %7 = getelementptr inbounds i8, ptr %self1.i.i, i64 8
  %v.0.i.i = load ptr, ptr %7, align 8, !noalias !2900
  %8 = getelementptr inbounds i8, ptr %self1.i.i, i64 16
  %v.1.i.i = load i64, ptr %8, align 8, !noalias !2900
  br i1 %6, label %bb6.i.i, label %bb2.i

bb6.i.i:                                          ; preds = %bb1
  call void @llvm.lifetime.end.p0(i64 40, ptr nonnull %self1.i.i), !noalias !2900
  call void @llvm.experimental.noalias.scope.decl(metadata !2908)
  call void @llvm.experimental.noalias.scope.decl(metadata !2911)
  %_3.not.i.i.i = icmp eq i64 %v.1.i.i, 8
  br i1 %_3.not.i.i.i, label %"core::result::Result<T,E>::unwrap.exit", label %bb1.i.i.i

bb1.i.i.i:                                        ; preds = %bb6.i.i
; call core::slice::<impl [T]>::copy_from_slice::len_mismatch_fail
  call void @"core::slice::<impl [T]>::copy_from_slice::len_mismatch_fail"(i64 noundef 8, i64 noundef %v.1.i.i, ptr noalias noundef nonnull readonly align 8 dereferenceable(24) @alloc_825ed530fe0ece941722f5f5e2ef3a35) #20, !noalias !2913
  unreachable

bb2.i:                                            ; preds = %bb1
  %e.sroa.7.0.self1.sroa_idx.i.i = getelementptr inbounds i8, ptr %self1.i.i, i64 24
  %_6.sroa.10.0.e.i.sroa_idx = getelementptr inbounds i8, ptr %e.i, i64 24
  call void @llvm.lifetime.start.p0(i64 40, ptr nonnull %e.i), !noalias !2914
  call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 8 dereferenceable(16) %_6.sroa.10.0.e.i.sroa_idx, ptr noundef nonnull align 8 dereferenceable(16) %e.sroa.7.0.self1.sroa_idx.i.i, i64 16, i1 false), !noalias !27
  call void @llvm.lifetime.end.p0(i64 40, ptr nonnull %self1.i.i), !noalias !2900
  %9 = ptrtoint ptr %v.0.i.i to i64
  store i64 %5, ptr %e.i, align 8, !noalias !2918
  %_6.sroa.6.0.e.i.sroa_idx = getelementptr inbounds i8, ptr %e.i, i64 8
  store i64 %9, ptr %_6.sroa.6.0.e.i.sroa_idx, align 8, !noalias !2918
  %_6.sroa.9.0.e.i.sroa_idx = getelementptr inbounds i8, ptr %e.i, i64 16
  store i64 %v.1.i.i, ptr %_6.sroa.9.0.e.i.sroa_idx, align 8, !noalias !2918
; call core::result::unwrap_failed
  call void @core::result::unwrap_failed(ptr noalias noundef nonnull readonly align 1 @alloc_00ae4b301f7fab8ac9617c03fcbd7274, i64 noundef 43, ptr noundef nonnull align 1 %e.i, ptr noalias noundef nonnull readonly align 8 dereferenceable(24) @vtable.2, ptr noalias noundef nonnull readonly align 8 dereferenceable(24) @alloc_579c227a4403128ce5fbcc2607f38818) #20, !noalias !2919
  unreachable

"core::result::Result<T,E>::unwrap.exit": ; preds = %bb6.i.i
  %buf.sroa.0.0.copyload6.i6.i = load i64, ptr %v.0.i.i, align 1, !alias.scope !2920, !noalias !2907
  store i64 %buf.sroa.0.0.copyload6.i6.i, ptr %3, align 8
  br label %bb4

bb4:                                              ; preds = %start, %"core::result::Result<T,E>::unwrap.exit"
  ret void
}

LLVM IR after this change:

; <rust_wasm_test_module::_::test_e__TableHandle as spacetimedb::table::Table>::integrate_generated_columns
; Function Attrs: noinline nounwind nonlazybind
define internal fastcc void @"<rust_wasm_test_module::_::test_e__TableHandle as spacetimedb::table::Table>::integrate_generated_columns"(ptr noalias nocapture noundef align 8 dereferenceable(32) %__row, ptr noalias nocapture noundef nonnull readonly align 1 %0, i64 noundef %1) unnamed_addr #5 personality ptr @rust_eh_personality {
start:
  %_4 = getelementptr inbounds i8, ptr %__row, i64 24
  %_2.i = load i64, ptr %_4, align 8, !alias.scope !2799, !noalias !2802, !noundef !27
  %_0.i = icmp eq i64 %_2.i, 0
  br i1 %_0.i, label %bb2.i, label %spacetimedb::table::SequenceTrigger::maybe_decode_into.exit

bb2.i:                                            ; preds = %start
  %_5.i.i = icmp ult i64 %1, 8
  br i1 %_5.i.i, label %bb10.i, label %bb11.i

bb11.i:                                           ; preds = %bb2.i
  %2 = load i64, ptr %0, align 1, !noalias !2805
  store i64 %2, ptr %_4, align 8, !alias.scope !2809, !noalias !2802
  br label %spacetimedb::table::SequenceTrigger::maybe_decode_into.exit

bb10.i:                                           ; preds = %bb2.i
; call spacetimedb::table::sequence_decode_error
  tail call void @spacetimedb::table::sequence_decode_error() #20
  unreachable

spacetimedb::table::SequenceTrigger::maybe_decode_into.exit: ; preds = %start, %bb11.i
  ret void
}

Expected complexity level and risk

1

[Centril]

Looks good, with some optional suggestions (see above).

[bfops]

It sounds like @cloutiertyler wants to hold off on merging this for now, at least while we're assembling RC1