To keep cross-compiling straightforward, Cretonne shouldn't have any
behavior that depends on the host. This renames the "Native" calling
convention to "SystemV", which has a defined meaning for each target,
so that it's clear that the calling convention doesn't change
depending on what host Cretonne is running on.
These tests were only using "test compile" because it doesn't require
any filecheck directives to be present, so just stop requiring filecheck
directives for "test regalloc" and other filecheck-based test drivers.
Fixes#178.
When an instruction with a fixed output operand defines a globally live
SSA value, we need to check if the fixed register is available in the
`regs.global` set of registers that can be used across EBB boundaries.
If the fixed output register is not available in regs.global, set the
replace_global_defines flag so the output operands are rewritten as
local values.
