r255606 - in /trunk/gcc: ChangeLog combine.c te...

[segher@gcc.gnu.org]

Author: segher
Date: Wed Dec 13 14:05:57 2017
New Revision: 255606

URL: https://gcc.gnu.org/viewcvs?rev=255606&root=gcc&view=rev
Log:
combine: Fix PR83393

In move_deaths we move a REG_DEAD note if the instruction combination
has extended the lifetime of a register so that the existing note is
no longer valid.  We find that note using reg_stat, but what that finds
can refer to a later insn.  If so, we cannot use the cached value.  This
patch implements that.


	PR rtl-optimization/83393
	* combine.c (move_deaths): If reg_stat points to a too new insn in
	last_death, do not use it: find the proper insn instead.

gcc/testsuite/
	PR rtl-optimization/83393
	* gcc.dg/pr83393.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/pr83393.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/combine.c
    trunk/gcc/testsuite/ChangeLog