Slightly optimize skipping of a binary segment

bjorng · Aug 21, 2023 · e7d2ce0 · e7d2ce0
1 parent e86952e
commit e7d2ce0
Showing 1 changed file with 17 additions and 0 deletions.
diff --git a/erts/emulator/beam/jit/arm/instr_bs.cpp b/erts/emulator/beam/jit/arm/instr_bs.cpp
@@ -891,6 +891,23 @@ void BeamModuleAssembler::emit_i_bs_skip_bits2(const ArgRegister &Ctx,
         a.cmp(TMP3, TMP4);
         a.b_hi(resolve_beam_label(Fail, disp1MB));
 
+        a.stur(TMP3, emit_boxed_val(ctx.reg, position_offset));
+    } else if (Unit.get() == 8) {
+        const int position_offset = offsetof(ErlBinMatchState, mb.offset);
+        const int size_offset = offsetof(ErlBinMatchState, mb.size);
+        auto [ctx, size] = load_sources(Ctx, TMP1, Size, TMP2);
+
+        a.eor(ARG1, size.reg, imm(_TAG_IMMED1_SMALL));
+        a.tst(ARG1, imm(0xFFF0000000000000UL | _TAG_IMMED1_MASK));
+        a.b_ne(resolve_beam_label(Fail, disp1MB));
+
+        a.ldur(TMP3, emit_boxed_val(ctx.reg, position_offset));
+        a.ldur(TMP4, emit_boxed_val(ctx.reg, size_offset));
+
+        a.add(TMP3, TMP3, ARG1, arm::lsr(1));
+        a.cmp(TMP3, TMP4);
+        a.b_hi(resolve_beam_label(Fail, disp1MB));
+
         a.stur(TMP3, emit_boxed_val(ctx.reg, position_offset));
     } else if (emit_bs_get_field_size(Size, Unit.get(), fail, ARG1) >= 0) {
         emit_bs_skip_bits(Fail, Ctx);