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Question about SUBREG handling in get_last_value

In looking at the testresults for hppa64-hp-hpux11.00, there are a few
FAILs due to aborts in simplify_gen_subreg when it is called with
innermode==VOIDmode.  This happens for example in compile/20000420-2.c
at -O1.

The problem arises with this situation in get_last_value:

(gdb) p debug_rtx (x)

(subreg:SI (reg:DI 28 %r28) 4)

(gdb) p debug_rtx (reg_last_set_value[28])

(call (clobber:SI (const_int 0 [0x0]))
    (const_int 64 [0x40]))

As can be seen, the last value is VOIDmode and the attempt to
simplify it in gen_lowpart_for_combine leads to the abort.  It
looks like `clobber:SI (const_int 0 [0x0])' might have been
substituted before the call to last value where the abort

Should get_last_value not call gen_lowpart_for_combine when the
last value is VOIDmode or does gen_lowpart_for_combine need fixing
so it doesn't call simplify_gen_subreg with innermode=VOIDmode?

J. David Anglin                        
National Research Council of Canada              (613) 990-0752 (FAX: 952-6605)

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