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cgen: ww str for-range loop-var narrows to MOVZBQ -- Phase 2 step-3 Fold 1 (align-up)

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Ranging a str (for (let b .. = s)) and reading the loop var back emitted MOVZBQ on cstage (correct u8 zero-extend) but MOVQ on wwstage (the missed case, #14). Align wwstage UP. ww cgforrange derived the element-type node only for slice/array; for a str scrutinee it left elemt=nil, so the loop var registered with no type and localloadop short-circuited to MOVQ. Fix: for a str scrutinee, synthesize a u8 element node (type_ = str.sub = u8, from F1) as elemt, so localadd hands the loop var a u8 tnode and the GENERIC narrow-load fires (MOVZBQ) -- consuming str.sub as F1 intended, mirroring how []u8 supplies its element node. NOT an if-str special-case. cstage already correct, untouched (ww-only). str's own type stays nominal.

GATE is the ASM SHAPE byte-id (cstage==wwstage at the loop-var read), NOT a runtime probe: the divergence is runtime-benign (MOVQ and MOVZBQ read the same zero-extended byte) so a runtime test passes both ways and cannot distinguish -- it was a byte-id-INVISIBLE divergence (990-997 green despite cstage!=ww, since no bootstrap input exercises a narrow-read str loop var). Verified fail-pre (the cstage-MOVZBQ vs wwstage-MOVQ 1-line diff) / pass-post (.s byte-identical). []u8/slice/array for-range emission unchanged. test/wcc/940 carries the fixture (runtime corpus coverage, both drivers).

main.combined.ww regenerated via the canonical make path.
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Hojun-Cho
2026-05-24 17:29:20 +09:00
parent 80527f3868
commit 3d7c707bd2
5 changed files with 239 additions and 0 deletions
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@@ -262,6 +262,7 @@ TESTS = $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
$(BIN)/test_str_arrfield_store_cap_run \
$(BIN)/test_str_chainfield_store_cap_run \
$(BIN)/test_str_massign_store_cap_run \
$(BIN)/test_str_forrange_loopvar_run \
$(BIN)/test_composite_call_arg \
$(BIN)/test_composite_call_arg_run \
$(BIN)/test_letdecl_zeroinit \
@@ -676,6 +677,12 @@ $(BIN)/test_str_massign_store_cap_run: test/wcc/939_str_massign_store_cap_run.c
$(LIB)/libwwrt.a | $(BIN)
$(CC) $(CFLAGS) -o $@ $<
$(BIN)/test_str_forrange_loopvar_run: test/wcc/940_str_forrange_loopvar_run.c \
$(BIN)/ww $(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
$(LIB)/libwwrt.a | $(BIN)
$(CC) $(CFLAGS) -o $@ $<
$(BIN)/test_composite_call_arg: test/wcc/723_composite_call_arg.c \
$(BIN)/w6c $(BIN)/w6c_ww | $(BIN)
$(CC) $(CFLAGS) -o $@ $<