diff options
| author | Segher Boessenkool <segher@kernel.crashing.org> | 2018-05-09 14:14:39 +0200 |
|---|---|---|
| committer | Segher Boessenkool <segher@gcc.gnu.org> | 2018-05-09 14:14:39 +0200 |
| commit | 97741c118180621e47edb6350571077eb0bc28ca (patch) | |
| tree | c5f025e476cf9eefd6c08e8d563901a3f6d13eb7 /gcc/regrename.c | |
| parent | c35533d7e97fda61c50be8b8260157956cf388e2 (diff) | |
regrename: Don't rename the dest of a REG_CFA_REGISTER (PR85645)
We should never change the destination of a REG_CFA_REGISTER, just
like for insns with a REG_CFA_RESTORE, because we need to have the
same control flow information on all branches that join. It is very
doubtful that renaming the scratch registers used for prologue/epilogue
will help anything either.
PR rtl-optimization/85645
* regrename.c (build_def_use): Also kill the chains that include the
destination of a REG_CFA_REGISTER note.
From-SVN: r260075
Diffstat (limited to 'gcc/regrename.c')
| -rw-r--r-- | gcc/regrename.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/gcc/regrename.c b/gcc/regrename.c index 45754812f6c..84240930e3a 100644 --- a/gcc/regrename.c +++ b/gcc/regrename.c @@ -1661,7 +1661,8 @@ 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. + (8) For any REG_CFA_RESTORE or REG_CFA_REGISTER, kill any chain + containing its dest. 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 @@ -1882,10 +1883,20 @@ build_def_use (basic_block bb) } /* Step 8: Kill the chains involving register restores. Those - should restore _that_ register. */ + should restore _that_ register. Similar for REG_CFA_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); + if (REG_NOTE_KIND (note) == REG_CFA_RESTORE + || REG_NOTE_KIND (note) == REG_CFA_REGISTER) + { + rtx *x = &XEXP (note, 0); + if (!*x) + x = &PATTERN (insn); + if (GET_CODE (*x) == PARALLEL) + x = &XVECEXP (*x, 0, 0); + if (GET_CODE (*x) == SET) + x = &SET_DEST (*x); + scan_rtx (insn, x, NO_REGS, mark_all_read, OP_IN); + } } else if (DEBUG_BIND_INSN_P (insn) && !VAR_LOC_UNKNOWN_P (INSN_VAR_LOCATION_LOC (insn))) |