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| author | Alexandre Oliva <aoliva@redhat.com> | 2004-11-26 18:53:47 +0000 |
|---|---|---|
| committer | Alexandre Oliva <aoliva@gcc.gnu.org> | 2004-11-26 18:53:47 +0000 |
| commit | 9a228f097b5cd72555cdb1e3f61ae92efd7d6b72 (patch) | |
| tree | a001e3858f4374f3c3b708de798f375c313ddf58 /gcc/config/frv | |
| parent | 532815a787849962ca2f2101aef12ec1d57b2cfd (diff) | |
| download | gcc-9a228f097b5cd72555cdb1e3f61ae92efd7d6b72.tar.gz | |
frv.c (frv_ifcvt_modify_insn): Don't leave alone scratch insns that set a register live at the join point.
* config/frv/frv.c (frv_ifcvt_modify_insn): Don't leave alone
scratch insns that set a register live at the join point.
From-SVN: r91344
Diffstat (limited to 'gcc/config/frv')
| -rw-r--r-- | gcc/config/frv/frv.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/gcc/config/frv/frv.c b/gcc/config/frv/frv.c index 19faaa67592..de976898d97 100644 --- a/gcc/config/frv/frv.c +++ b/gcc/config/frv/frv.c @@ -7418,10 +7418,28 @@ frv_ifcvt_modify_insn (ce_if_block_t *ce_info, else if (frv_ifcvt.scratch_insns_bitmap && bitmap_bit_p (frv_ifcvt.scratch_insns_bitmap, INSN_UID (insn)) - /* We must not unconditionally set a reg set used as - scratch in the THEN branch if the same reg is live - in the ELSE branch. */ && REG_P (SET_DEST (set)) + /* We must not unconditionally set a scratch reg chosen + for a nested if-converted block if its incoming + value from the TEST block (or the result of the THEN + branch) could/should propagate to the JOIN block. + It suffices to test whether the register is live at + the JOIN point: if it's live there, we can infer + that we set it in the former JOIN block of the + nested if-converted block (otherwise it wouldn't + have been available as a scratch register), and it + is either propagated through or set in the other + conditional block. It's probably not worth trying + to catch the latter case, and it could actually + limit scheduling of the combined block quite + severely. */ + && ce_info->join_bb + && ! (REGNO_REG_SET_P + (ce_info->join_bb->global_live_at_start, + REGNO (SET_DEST (set)))) + /* Similarly, we must not unconditionally set a reg + used as scratch in the THEN branch if the same reg + is live in the ELSE branch. */ && (! ce_info->else_bb || BLOCK_FOR_INSN (insn) == ce_info->else_bb || ! (REGNO_REG_SET_P |