From: Sergey Grechanik <mouseent...@condor.intra.ispras.ru>
This patch avoids changing speculative bits of a register use when it is moved
up above a speculation check where that register is used as the address
register. We should only call ds_full_merge when the producer (speculation
check) writes to a register.
(A similar check was in place when selective scheduler was in active
development, but was dropped before it was merged, probably by accident)
2011-08-04 Sergey Grechanik <mouseent...@ispras.ru>
* sel-sched-ir.c (has_dependence_note_reg_use): Call ds_full_merge
only if producer writes to the register given by regno.
diff --git a/gcc/sel-sched-ir.c b/gcc/sel-sched-ir.c
index 91f9dd9..745fcc1 100644
--- a/gcc/sel-sched-ir.c
+++ b/gcc/sel-sched-ir.c
@@ -3227,7 +3227,10 @@ has_dependence_note_reg_use (int regno)
pro_spec_checked_ds = INSN_SPEC_CHECKED_DS (has_dependence_data.pro);
pro_spec_checked_ds = ds_get_max_dep_weak (pro_spec_checked_ds);
- if (pro_spec_checked_ds != 0)
+ if (pro_spec_checked_ds != 0
+ /* FIXME: if mode for REGNO was available here, we could use
+ register_unavailable_p that tests all hard regs for mode. */
+ && bitmap_bit_p (INSN_REG_SETS (has_dependence_data.pro), regno))
/* Merge BE_IN_SPEC bits into *DSP. */
*dsp = ds_full_merge (*dsp, pro_spec_checked_ds,
NULL_RTX, NULL_RTX);
