On Wed, Oct 02, 2019 at 10:22:22PM +0100, Richard Sandiford wrote:
> My change to the -fipa-ra bookkeeping used ALL_REGS as the supposedly
> safe default assumption, but ALL_REGS isn't literally all registers,
> just a close approximation.
>
> This caused a bootstrap failure on arm-linux-gnu, where the condition
> code register isn't in ALL_REGS and so was being masked out of some
> call-clobbered sets.
The documentation says
@findex ALL_REGS
@findex NO_REGS
In general, each register will belong to several classes. In fact, one
class must be named @code{ALL_REGS} and contain all the registers. Another
class must be named @code{NO_REGS} and contain no registers. Often the
union of two classes will be another class; however, this is not required.
so is the arm port wrong, or is the documentation wrong? I think the arm
port simply forgets to include CC_REG, VFPCC_REG, SFP_REG, AFP_REG:
#define REG_CLASS_CONTENTS \
...
{ 0x00000000, 0x00000000, 0x00000000, 0x00000010 }, /* CC_REG */ \
{ 0x00000000, 0x00000000, 0x00000000, 0x00000020 }, /* VFPCC_REG */ \
{ 0x00000000, 0x00000000, 0x00000000, 0x00000040 }, /* SFP_REG */ \
{ 0x00000000, 0x00000000, 0x00000000, 0x00000080 }, /* AFP_REG */ \
{ 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000000F } /* ALL_REGS */ \
and that last number should be 0x000000ff instead?
Segher
