condition codes, haifa-sched and virtual-stack-vars

[Richard Henderson]

On Wed, Jan 30, 2002 at 11:59:59AM -0700, Greg McGary wrote:
> Later, global-reg alloc instantiates virtual-stack-vars as an
> offset from FP, so the move mutates into an add of fp+offset,
> clobbering the condition codes computed earlier in the bitfield test.

If you don't have a form of add that doesn't clobber condition
codes, you are screwed.  Reload absolutely relies on the existance
of such an instruction.

Your only hope is to represent compare+branch as a single insn
until after reload.


r~