Fixes #783 and reverts to unsigned FLINT_BIT_COUNT.

flintlib · Jul 7, 2020 · 5010d74 · 5010d74
1 parent c8ff8a3
commit 5010d74
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Showing 2 changed files with 4 additions and 3 deletions.
diff --git a/flint.h b/flint.h
@@ -311,12 +311,13 @@ typedef __mpfr_struct flint_mpfr;
 FLINT_DLL extern const unsigned char __flint_clz_tab[128];
 #endif
 
+/* Beware when using the unsigned return value in signed arithmetic */
 static __inline__
-slong FLINT_BIT_COUNT(mp_limb_t x)
+mp_limb_t FLINT_BIT_COUNT(mp_limb_t x)
 {
    mp_limb_t zeros = FLINT_BITS;
    if (x) count_leading_zeros(zeros, x);
-   return (slong) (FLINT_BITS - zeros);
+   return FLINT_BITS - zeros;
 }
 
 #define FLINT_FLOG2(k)  (FLINT_BIT_COUNT(k) - 1)

diff --git a/fmpz_mat/next_col_van_hoeij.c b/fmpz_mat/next_col_van_hoeij.c
@@ -84,7 +84,7 @@ int fmpz_mat_next_col_van_hoeij(fmpz_mat_t M, fmpz_t P,
    k = fmpz_bits(P) - bit_r - bit_r/2;
 
    /* check if LLL justified */
-   if (k < exp + FLINT_BIT_COUNT(r + 1))
+   if (k < exp + (slong) FLINT_BIT_COUNT(r + 1))
       return 0;
 
    fmpz_init(P_trunc);