The code 'if (foo & X) foo &= ~X;' is semantically equivalent to simply 'foo &= ~X;', but gcc generates about four instructions for the former, one for the latter. Similarly, if X consists of a single bit, 'if (!(foo & X)) X |= X;' can be replaced by 'foo |= X;'.
In the atl2 case, gcc does know how to merge the new adjacent operations, so altogether this gives a nice little code size reduction of about 80 bytes. Signed-off-by: Rasmus Villemoes <[email protected]> --- drivers/net/ethernet/atheros/atlx/atl1.c | 3 +-- drivers/net/ethernet/atheros/atlx/atl2.c | 12 ++++-------- 2 files changed, 5 insertions(+), 10 deletions(-) diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c index 2c8f398aeda9..d9d61d6e8386 100644 --- a/drivers/net/ethernet/atheros/atlx/atl1.c +++ b/drivers/net/ethernet/atheros/atlx/atl1.c @@ -1667,8 +1667,7 @@ static void atl1_via_workaround(struct atl1_adapter *adapter) unsigned long value; value = ioread16(adapter->hw.hw_addr + PCI_COMMAND); - if (value & PCI_COMMAND_INTX_DISABLE) - value &= ~PCI_COMMAND_INTX_DISABLE; + value &= ~PCI_COMMAND_INTX_DISABLE; iowrite32(value, adapter->hw.hw_addr + PCI_COMMAND); } diff --git a/drivers/net/ethernet/atheros/atlx/atl2.c b/drivers/net/ethernet/atheros/atlx/atl2.c index 84a09e8ddd9c..46d1b959daa8 100644 --- a/drivers/net/ethernet/atheros/atlx/atl2.c +++ b/drivers/net/ethernet/atheros/atlx/atl2.c @@ -1278,14 +1278,10 @@ static void atl2_setup_pcicmd(struct pci_dev *pdev) pci_read_config_word(pdev, PCI_COMMAND, &cmd); - if (cmd & PCI_COMMAND_INTX_DISABLE) - cmd &= ~PCI_COMMAND_INTX_DISABLE; - if (cmd & PCI_COMMAND_IO) - cmd &= ~PCI_COMMAND_IO; - if (0 == (cmd & PCI_COMMAND_MEMORY)) - cmd |= PCI_COMMAND_MEMORY; - if (0 == (cmd & PCI_COMMAND_MASTER)) - cmd |= PCI_COMMAND_MASTER; + cmd &= ~PCI_COMMAND_INTX_DISABLE; + cmd &= ~PCI_COMMAND_IO; + cmd |= PCI_COMMAND_MEMORY; + cmd |= PCI_COMMAND_MASTER; pci_write_config_word(pdev, PCI_COMMAND, cmd); /* -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
