diff options
Diffstat (limited to 'gcc/combine.cc')
| -rw-r--r-- | gcc/combine.cc | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/gcc/combine.cc b/gcc/combine.cc index 5f08518..873c2bd 100644 --- a/gcc/combine.cc +++ b/gcc/combine.cc @@ -815,7 +815,7 @@ do_SUBST_LINK (struct insn_link **into, struct insn_link *newval) #define SUBST_LINK(oldval, newval) do_SUBST_LINK (&oldval, newval) /* Subroutine of try_combine. Determine whether the replacement patterns - NEWPAT, NEWI2PAT and NEWOTHERPAT are cheaper according to insn_cost + NEWPAT, NEWI2PAT and NEWOTHERPAT are more expensive according to insn_cost than the original sequence I0, I1, I2, I3 and undobuf.other_insn. Note that I0, I1 and/or NEWI2PAT may be NULL_RTX. Similarly, NEWOTHERPAT and undobuf.other_insn may also both be NULL_RTX. Return false if the cost @@ -4129,8 +4129,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, } } - /* Only allow this combination if insn_cost reports that the - replacement instructions are cheaper than the originals. */ + /* Reject this combination if insn_cost reports that the replacement + instructions are more expensive than the originals. */ if (!combine_validate_cost (i0, i1, i2, i3, newpat, newi2pat, other_pat)) { undo_all (); @@ -5280,6 +5280,12 @@ find_split_point (rtx *loc, rtx_insn *insn, bool set_src) SUBST (XEXP (x, 0), XEXP (x, 1)); SUBST (XEXP (x, 1), tem); } + /* Many targets have a `(and (not X) Y)` and/or `(ior (not X) Y)` instructions. + Split at that insns. However if this is + the SET_SRC, we likely do not have such an instruction and it's + worthless to try this split. */ + if (!set_src && GET_CODE (XEXP (x, 0)) == NOT) + return loc; break; case PLUS: |