re PR rtl-optimization/23478 (Miscompilation due to reloading of a var that is also...

re PR rtl-optimization/23478 (Miscompilation due to reloading of a var that is also used in EH pad)

	PR rtl-optimization/23478
	* regs.h (reg_info): Add throw_calls_crossed.
	(REG_N_THROWING_CALLS_CROSSED): Define.
	* flow.c (allocate_reg_life_data): Initialize
	REG_N_THROWING_CALLS_CROSSED.
	(propagate_one_insn, attempt_auto_inc): Update
	REG_N_THROWING_CALLS_CROSSED.
	* global.c (global_alloc): Don't allocate pseudos across
	calls that may throw.

	* g++.dg/opt/pr23478.C: New test.

From-SVN: r103348