Hi!
As the testcase in the PR (unfortunately only reproduceable after reverting
some inlining patch, so not including that testcase in the patch) shows,
loc_equivalence_change_p isn't good enough for debug_insns, when a REG is
substituted for VOIDmode constant. In that case, the surrounding SUBREG
(handled in loc_equivalence_change_p), but also other operations like
ZERO_EXTEND/SIGN_EXTEND, ZERO_EXTRACT etc. need to be simplified while we
still know the original mode, and perhaps several times, as SIGN_EXTEND
might be in another ZERO_EXTEND etc. The best way to deal with that
is simplify_replace_fn_rtx which is used in various other places in the
compiler.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2012-12-11 Jakub Jelinek <ja...@redhat.com>
PR rtl-optimization/55193
* lra-constraints.c (loc_equivalence_callback): New function.
(lra_constraints): Call simplify_replace_fn_rtx instead of
loc_equivalence_change_p on DEBUG_INSNs.
--- gcc/lra-constraints.c.jj 2012-12-10 08:42:40.000000000 +0100
+++ gcc/lra-constraints.c 2012-12-10 18:43:04.977277475 +0100
@@ -3186,6 +3186,21 @@ loc_equivalence_change_p (rtx *loc)
return result;
}
+/* Similar to loc_equivalence_change_p, but for use as
+ simplify_replace_fn_rtx callback. */
+static rtx
+loc_equivalence_callback (rtx loc, const_rtx, void *)
+{
+ if (!REG_P (loc))
+ return NULL_RTX;
+
+ rtx subst = get_equiv_substitution (loc);
+ if (subst != loc)
+ return subst;
+
+ return NULL_RTX;
+}
+
/* Maximum allowed number of constraint pass iterations after the last
spill pass. It is for preventing LRA cycling in a bug case. */
#define MAX_CONSTRAINT_ITERATION_NUMBER 30
@@ -3422,11 +3437,17 @@ lra_constraints (bool first_p)
/* We need to check equivalence in debug insn and change
pseudo to the equivalent value if necessary. */
curr_id = lra_get_insn_recog_data (curr_insn);
- if (bitmap_bit_p (&equiv_insn_bitmap, INSN_UID (curr_insn))
- && loc_equivalence_change_p (curr_id->operand_loc[0]))
+ if (bitmap_bit_p (&equiv_insn_bitmap, INSN_UID (curr_insn)))
{
- lra_update_insn_regno_info (curr_insn);
- changed_p = true;
+ rtx old = *curr_id->operand_loc[0];
+ *curr_id->operand_loc[0]
+ = simplify_replace_fn_rtx (old, NULL_RTX,
+ loc_equivalence_callback, NULL);
+ if (old != *curr_id->operand_loc[0])
+ {
+ lra_update_insn_regno_info (curr_insn);
+ changed_p = true;
+ }
}
}
else if (INSN_P (curr_insn))
Jakub
