boot2

Playing with the boostrap
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080-uneg-canonical.scm (862B)

      1 ;; tests/cc-cg/80-uneg-canonical.scm — unary minus on unsigned should
      2 ;; leave the canonical 64-bit slot in the to-type's natural form.
      3 ;;
      4 ;; Models:
      5 ;;   unsigned int a = 1;
      6 ;;   return ((unsigned)-a) == 4294967295u;  /* (u32)-1u == UINT_MAX */
      7 ;;
      8 ;; Bug: cg-unop neg computes 0 - canonical(1) = 0xFFFFFFFFFFFFFFFF and
      9 ;; spills as u32. Without re-canonicalizing the spill (zext32), a
     10 ;; subsequent compare against the literal 4294967295 (which %li loads
     11 ;; as 0x00000000FFFFFFFF) sees mismatched upper bits → equality 0.
     12 ;; Correct cg masks/zext on spill of an unsigned-typed result.
     13 ;; Exit code: 1 if equal, 0 otherwise.
     14 
     15 (let ((cg (cg-init)))
     16   (cg-fn-begin cg "main" '() %t-i32)
     17   (cg-push-imm cg %t-u32 1)
     18   (cg-unop cg 'neg)
     19   (cg-push-imm cg %t-u32 4294967295)
     20   (cg-binop cg 'eq)
     21   (cg-return cg)
     22   (cg-fn-end cg)
     23   (write-bv-fd 1 (cg-finish cg)))