r266734 - in /trunk/gcc: ChangeLog cfgcleanup.c...

[iii@gcc.gnu.org]

Author: iii
Date: Mon Dec  3 09:49:02 2018
New Revision: 266734

URL: https://gcc.gnu.org/viewcvs?rev=266734&root=gcc&view=rev
Log:
Repeat jump threading after combine

Consider the following RTL:

(insn (set (reg 65) (if_then_else (eq %cc 0) 1 0)))
(insn (parallel [(set %cc (compare (reg 65) 0)) (clobber %scratch)]))
(jump_insn (set %pc (if_then_else (ne %cc 0) (label_ref 23) %pc)))

Combine simplifies this into:

(note NOTE_INSN_DELETED)
(note NOTE_INSN_DELETED)
(jump_insn (set %pc (if_then_else (eq %cc 0) (label_ref 23) %pc)))

opening up the possibility to perform jump threading.

gcc/ChangeLog:

2018-12-03  Ilya Leoshkevich  <iii@linux.ibm.com>

	PR target/80080
	* cfgcleanup.c (class pass_postreload_jump): New pass.
	(pass_postreload_jump::execute): Likewise.
	(make_pass_postreload_jump): Likewise.
	* passes.def: Add pass_postreload_jump before
	pass_postreload_cse.
	* tree-pass.h (make_pass_postreload_jump): New pass.

gcc/testsuite/ChangeLog:

2018-12-03  Ilya Leoshkevich  <iii@linux.ibm.com>

	PR target/80080
	* gcc.target/s390/pr80080-4.c: New test.

Added:
    trunk/gcc/testsuite/gcc.target/s390/pr80080-4.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgcleanup.c
    trunk/gcc/passes.def
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-pass.h