Index: sys/dev/aic7xxx/aic79xx.c
===================================================================
--- sys/dev/aic7xxx/aic79xx.c
+++ sys/dev/aic7xxx/aic79xx.c
@@ -8593,8 +8593,7 @@
 	if (sg_prefetch_align == 0)
 		sg_prefetch_align = 8;
 	/* Round down to the nearest power of 2. */
-	while (powerof2(sg_prefetch_align) == 0)
-		sg_prefetch_align--;
+	sg_prefetch_align = 1 << ilog2(sg_prefetch_align);
 
 	cacheline_mask = sg_prefetch_align - 1;
 
Index: sys/dev/cxgb/cxgb_sge.c
===================================================================
--- sys/dev/cxgb/cxgb_sge.c
+++ sys/dev/cxgb/cxgb_sge.c
@@ -553,9 +553,7 @@
 	nqsets *= adap->params.nports;
 
 	fl_q_size = min(nmbclusters/(3*nqsets), FL_Q_SIZE);
-
-	while (!powerof2(fl_q_size))
-		fl_q_size--;
+	fl_q_size = 1 << ilog2(fl_q_size);
 
 	use_16k = cxgb_use_16k_clusters != -1 ? cxgb_use_16k_clusters :
 	    is_offload(adap);
@@ -567,8 +565,7 @@
 		jumbo_q_size = min(nmbjumbo9/(3*nqsets), JUMBO_Q_SIZE);
 		jumbo_buf_size = MJUM9BYTES;
 	}
-	while (!powerof2(jumbo_q_size))
-		jumbo_q_size--;
+	jumbo_q_size = 1 << ilog2(jumbo_q_size);
 
 	if (fl_q_size < (FL_Q_SIZE / 4) || jumbo_q_size < (JUMBO_Q_SIZE / 2))
 		device_printf(adap->dev,
Index: sys/dev/cxgbe/t4_sge.c
===================================================================
--- sys/dev/cxgbe/t4_sge.c
+++ sys/dev/cxgbe/t4_sge.c
@@ -4220,9 +4220,7 @@
 {
 	u_int fthresh;
 
-	while (!powerof2(qsize))
-		qsize++;
-	fthresh = ilog2(qsize);
+	fthresh = qsize == 0 ? 0 : fls(qsize - 1);
 	if (fthresh > X_CIDXFLUSHTHRESH_128)
 		fthresh = X_CIDXFLUSHTHRESH_128;
 
Index: sys/dev/irdma/irdma_ctrl.c
===================================================================
--- sys/dev/irdma/irdma_ctrl.c
+++ sys/dev/irdma/irdma_ctrl.c
@@ -4909,7 +4909,7 @@
 	struct irdma_virt_mem virt_mem;
 	u32 i, mem_size;
 	u32 qpwanted, mrwanted, pblewanted;
-	u32 powerof2, hte;
+	u32 hte;
 	u32 sd_needed;
 	u32 sd_diff;
 	u32 loop_count = 0;
@@ -4938,12 +4938,8 @@
 		    hmc_info->sd_table.sd_cnt, max_sds);
 
 	qpwanted = min(qp_count, hmc_info->hmc_obj[IRDMA_HMC_IW_QP].max_cnt);
-
-	powerof2 = 1;
-	while (powerof2 <= qpwanted)
-		powerof2 *= 2;
-	powerof2 /= 2;
-	qpwanted = powerof2;
+	if (qpwanted != 0)
+		qpwanted = 1 << ilog2(qpwanted);
 
 	mrwanted = hmc_info->hmc_obj[IRDMA_HMC_IW_MR].max_cnt;
 	pblewanted = hmc_info->hmc_obj[IRDMA_HMC_IW_PBLE].max_cnt;
@@ -4986,11 +4982,9 @@
 		hmc_info->hmc_obj[IRDMA_HMC_IW_MR].cnt = mrwanted;
 
 		hte = round_up(qpwanted + hmc_info->hmc_obj[IRDMA_HMC_IW_FSIMC].cnt, 512);
-		powerof2 = 1;
-		while (powerof2 < hte)
-			powerof2 *= 2;
+		hte = hte == 0 ? 1 : 1 << fls(hte - 1);
 		hmc_info->hmc_obj[IRDMA_HMC_IW_HTE].cnt =
-		    powerof2 * hmc_fpm_misc->ht_multiplier;
+		    hte * hmc_fpm_misc->ht_multiplier;
 		if (dev->hw_attrs.uk_attrs.hw_rev == IRDMA_GEN_1)
 			cfg_fpm_value_gen_1(dev, hmc_info, qpwanted);
 		else
Index: sys/dev/mlx5/mlx5_en/mlx5_en_main.c
===================================================================
--- sys/dev/mlx5/mlx5_en/mlx5_en_main.c
+++ sys/dev/mlx5/mlx5_en/mlx5_en_main.c
@@ -2331,9 +2331,7 @@
 	 * Stride size is 16 * (n + 1), as the first segment is
 	 * control.
 	 */
-	for (n = howmany(r, MLX5E_MAX_RX_BYTES); !powerof2(n + 1); n++)
-		;
-
+	n = (1 << fls(howmany(r, MLX5E_MAX_RX_BYTES))) - 1;
 	if (n > MLX5E_MAX_BUSDMA_RX_SEGS)
 		return (-ENOMEM);
 
Index: sys/netpfil/ipfw/ip_fw_table.c
===================================================================
--- sys/netpfil/ipfw/ip_fw_table.c
+++ sys/netpfil/ipfw/ip_fw_table.c
@@ -1516,15 +1516,7 @@
 roundup2p(uint32_t v)
 {
 
-	v--;
-	v |= v >> 1;
-	v |= v >> 2;
-	v |= v >> 4;
-	v |= v >> 8;
-	v |= v >> 16;
-	v++;
-
-	return (v);
+	return (1 << fls(v - 1));
 }
 
 /*