[Bug target/26459] [4.1/4.2 Regression] gcc fails to build on powerpc e500-double targets

["amodra at bigpond dot net dot au" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #15 from amodra at bigpond dot net dot au  2006-03-24 14:23 -------
Appears to be the peephole in rs6000.md immediately after this comment:
;; after inserting conditional returns we can sometimes have
;; unnecessary register moves.

(subreg:DF (reg:DI 3 3 [128]) 0) is a valid gpc_reg_operand.  Try this (totally
untested) patch.

Index: gcc/config/rs6000/rs6000.md
===================================================================
--- gcc/config/rs6000/rs6000.md (revision 112347)
+++ gcc/config/rs6000/rs6000.md (working copy)
@@ -9771,18 +9771,20 @@
   "operands[0] = widen_memory_access (operands[0], V2DFmode, 0);
    operands[1] = gen_rtx_REG (V2DFmode, REGNO (operands[1]));")

-;; after inserting conditional returns we can sometimes have
+;; After inserting conditional returns we can sometimes have
 ;; unnecessary register moves.  Unfortunately we cannot have a
 ;; modeless peephole here, because some single SImode sets have early
 ;; clobber outputs.  Although those sets expand to multi-ppc-insn
 ;; sequences, using get_attr_length here will smash the operands
 ;; array.  Neither is there an early_cobbler_p predicate.
+;; Disallow subregs for E500 so we don't munge frob_di_df_2.
 (define_peephole2
   [(set (match_operand:DF 0 "gpc_reg_operand" "")
        (match_operand:DF 1 "any_operand" ""))
    (set (match_operand:DF 2 "gpc_reg_operand" "")
        (match_dup 0))]
-  "peep2_reg_dead_p (2, operands[0])"
+  "!(TARGET_E500_DOUBLE && GET_CODE (operands[2]) == SUBREG)
+   && peep2_reg_dead_p (2, operands[0])"
   [(set (match_dup 2) (match_dup 1))])

 (define_peephole2


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26459