[kbuild] drivers/spi/spi-cadence-quadspi.c:250:18: warning: Shifting signed 32-bit value by 31 bits is undefined behaviour

[Dan Carpenter]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git  master
head:   7a7fd0de4a9804299793e564a555a49c1fc924cb
commit: 31fb632b5d43ca16713095b3a4fe17e3d7331e28 spi: Move cadence-quadspi driver to drivers/spi/
compiler: nds32le-linux-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

cppcheck possible warnings: (new ones prefixed by >>, may not real problems)

>> drivers/spi/spi-cadence-quadspi.c:250:18: warning: Shifting signed 32-bit value by 31 bits is undefined behaviour [shiftTooManyBitsSigned]
    return reg & (1 << CQSPI_REG_CONFIG_IDLE_LSB);

vim +250 drivers/spi/spi-cadence-quadspi.c

14062341053690 drivers/mtd/spi-nor/cadence-quadspi.c Graham Moore 2016-06-04  246  static bool cqspi_is_idle(struct cqspi_st *cqspi)
14062341053690 drivers/mtd/spi-nor/cadence-quadspi.c Graham Moore 2016-06-04  247  {
14062341053690 drivers/mtd/spi-nor/cadence-quadspi.c Graham Moore 2016-06-04  248  	u32 reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
14062341053690 drivers/mtd/spi-nor/cadence-quadspi.c Graham Moore 2016-06-04  249  
14062341053690 drivers/mtd/spi-nor/cadence-quadspi.c Graham Moore 2016-06-04 @250  	return reg & (1 << CQSPI_REG_CONFIG_IDLE_LSB);
                                                                                                           ^^^^^^^^^^^^^^^^^^^^^^^^^
CQSPI_REG_CONFIG_IDLE_LSB is 31 and reg is a u32 so this is very
puzzling.

14062341053690 drivers/mtd/spi-nor/cadence-quadspi.c Graham Moore 2016-06-04  251  }

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