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regrename: Don't rename restores 

A restore is supposed to restore some certain register.  Restoring it
into some other register will not work.  Don't.


	* regrename.c (build_def_use): Invalidate chains that have a
	REG_CFA_RESTORE on some instruction.

From-SVN: r241061
This commit is contained in:
Segher Boessenkool 2016-10-12 17:23:11 +02:00 committed by Segher Boessenkool
parent aab648a9fc
commit d73c92c9f2
2 changed files with 12 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2016-10-12 Segher Boessenkool <segher@kernel.crashing.org>
* regrename.c (build_def_use): Invalidate chains that have a
REG_CFA_RESTORE on some instruction.
2016-10-12 Segher Boessenkool <segher@kernel.crashing.org>
* dce.c (delete_unmarked_insns): Don't delete instructions with

7
gcc/regrename.c
View File

@ -1655,6 +1655,7 @@ build_def_use (basic_block bb)
(6) For any non-earlyclobber write we find in an operand, make
a new chain or mark the hard register as live.
(7) For any REG_UNUSED, close any chains we just opened.
(8) For any REG_CFA_RESTORE, kill any chain containing it.
We cannot deal with situations where we track a reg in one mode
and see a reference in another mode; these will cause the chain
@ -1867,6 +1868,12 @@ build_def_use (basic_block bb)
scan_rtx (insn, &XEXP (note, 0), NO_REGS, terminate_dead,
OP_IN);
}
/* Step 8: Kill the chains involving register restores. Those
should restore _that_ register. */
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
if (REG_NOTE_KIND (note) == REG_CFA_RESTORE)
scan_rtx (insn, &XEXP (note, 0), NO_REGS, mark_all_read, OP_IN);
}
else if (DEBUG_INSN_P (insn)
&& !VAR_LOC_UNKNOWN_P (INSN_VAR_LOCATION_LOC (insn)))