Hello,
This PR is about wrong speculation of an insn that doesn't support storing
NaT bits done by the selective scheduler (more details in the PR audit
trail). The reason for this is the wrong one-liner patch committed last
year, the fix is to revert that patch and to clarify the comment before the
patched code.
Bootstrapped and tested on ia64, approved by Alexander offline. No test as
I don't know how to check whether an insn got moved through another insn.
Andrey
PR target/53975
* sel-sched-ir.c (has_dependence_note_reg_use): Clarify comment.
Revert
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.
Index: gcc/sel-sched-ir.c
===================================================================
*** gcc/sel-sched-ir.c (revision 190004)
--- gcc/sel-sched-ir.c (revision 190005)
*************** has_dependence_note_reg_use (int regno)
*** 3228,3234 ****
if (reg_last->clobbers)
*dsp = (*dsp & ~SPECULATIVE) | DEP_ANTI;
! /* Handle BE_IN_SPEC. */
if (reg_last->uses)
{
ds_t pro_spec_checked_ds;
--- 3228,3238 ----
if (reg_last->clobbers)
*dsp = (*dsp & ~SPECULATIVE) | DEP_ANTI;
! /* Merge BE_IN_SPEC bits into *DSP when the dependency producer
! is actually a check insn. We need to do this for any register
! read-read dependency with the check unless we track properly
! all registers written by BE_IN_SPEC-speculated insns, as
! we don't have explicit dependence lists. See PR 53975. */
if (reg_last->uses)
{
ds_t pro_spec_checked_ds;
*************** has_dependence_note_reg_use (int regno)
*** 3236,3244 ****
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
! && 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);
}
--- 3240,3246 ----
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)
*dsp = ds_full_merge (*dsp, pro_spec_checked_ds,
NULL_RTX, NULL_RTX);
}
