hbitmap: Use non-bitops ctzl

Both uses of ctz have already eliminated zero, and thus the difference
in edge conditions between the two routines is irrelevant.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

include/qemu/hbitmap.h

@@ -16,6 +16,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include "bitops.h"
+#include "host-utils.h"
 
 typedef struct HBitmap HBitmap;
 typedef struct HBitmapIter HBitmapIter;
@@ -170,7 +171,7 @@ static inline int64_t hbitmap_iter_next(HBitmapIter *hbi)
 
     /* The next call will resume work from the next bit.  */
     hbi->cur[HBITMAP_LEVELS - 1] = cur & (cur - 1);
-    item = ((uint64_t)hbi->pos << BITS_PER_LEVEL) + bitops_ctzl(cur);
+    item = ((uint64_t)hbi->pos << BITS_PER_LEVEL) + ctzl(cur);
 
     return item << hbi->granularity;
 }

util/hbitmap.c

@@ -126,7 +126,8 @@ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi)
          * The index of this word's least significant set bit provides
          * the low-order bits.
          */
-        pos = (pos << BITS_PER_LEVEL) + bitops_ctzl(cur);
+        assert(cur);
+        pos = (pos << BITS_PER_LEVEL) + ctzl(cur);
         hbi->cur[i] = cur & (cur - 1);
 
         /* Set up next level for iteration.  */