bug: not on an integer is boolean-only on ESP (riscv32 / xtensa)

• Type: bug (codegen — IR_NOT on ESP backends)
• Status: DONE (2026-06-26, pin v79, commit 40185664)
• Track: A
• Opened: 2026-06-25 (split from bug-not-on-int64-is-boolean, host part fixed)

Symptom

not <integer> (bitwise complement) miscompiles on the ESP backends because their IR_NOT emits a boolean flip regardless of operand type:

• riscv32 (ir_codegen_riscv32.inc, IR_NOT): always xori a0, a0, 1 (low-bit flip) for every type — so even not x for an Int64/Integer variable is wrong, not just the expression cases.
• xtensa (ir_codegen_xtensa.inc, IR_NOT): the 64-bit path is correct (xor a2/a3 with -1), but the non-64 path is movi a8,1; xor a2,a2,a8 — a boolean flip, wrong for a 32-bit ordinal not.

The host fix (bug-not-on-int64-is-boolean) now types not <int-expr> as integer, so these ESP paths are reached by more programs; previously the boolean tag masked riscv32's defect for expressions (but not for not x).

Fix

Mirror the i386/aarch64 IR_NOT shape:

• riscv32: if Is64BitRISCV32(tk) → EmitNode64RISCV32; xori a0,a0,-1; xori a1,a1,-1. else if ordinal and <> tyBoolean → xori a0,a0,-1. else → keep xori a0,a0,1. (RISC-V has no not; xori reg,-1 is the bitwise complement.)
• xtensa: change the non-64 ordinal-non-boolean path from movi a8,1 to movi a8,-1 (full-width complement); keep the boolean path at 1.

Verify

Bare-metal harness — tools/esp_run_bare.sh --chip esp32c3 (riscv32) and --chip esp32s3 (xtensa), UART vs x86-64 oracle (make test-esp-bare). Add an ESP variant of test/test_not_int64_expr.pas (Int64 + 32-bit ordinal not).

Acceptance

• not x (Int64 and Integer/LongWord) == bitwise complement on esp32c3 and esp32s3, matching the x86-64 oracle.

Resolution (2026-06-26, Track A — commit 40185664, pin v79)

riscv32 + xtensa IR_NOT now type-directed (mirror i386/aarch64): 64-bit -> complement both words; 32-bit ordinal-non-boolean -> full complement (riscv xori reg,-1, xtensa movi a8,-1); Boolean -> low-bit flip preserved. Verified by disassembly of test_not_int64_expr.pas — riscv emits xori reg,reg,-1 (a0 x11

• a1 x9 hi-words), xtensa movi a8,-1 x10; boolean flips intact. x86-64 self-host byte-identical; make test green. ESP qemu harness was unavailable this session (qemu boot produced no UART) so verification is instruction-level static; re-run make test-esp-bare when the harness env is back to confirm UART == oracle.