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References: <bug-44695-12544@http.gcc.gnu.org/bugzilla/>
Subject: [Bug rtl-optimization/44695] [4.6 Regression] ice in simplify_subreg, at simplify-rtx.c:5117
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------- Comment #2 from hjl dot tools at gmail dot com  2010-06-28 21:57 -------
I think it is a latent bug exposed by revision 161329. Now
x86 backend may generate:

(ior:HI (ashift:HI (zero_extend:HI (umod:QI (reg:HI 68)
                (reg:QI 61 [ D.2750 ])))
        (const_int 8 [0x8]))
    (zero_extend:HI (udiv:QI (reg:HI 68)
            (reg:QI 61 [ D.2750 ]))))

Combine ran into trouble:
(gdb) bt
#0  fancy_abort (
    file=0x11e5860 "/export/gnu/import/git/gcc/gcc/simplify-rtx.c", line=5117, 
    function=0x11e6be0 "simplify_subreg")
    at /export/gnu/import/git/gcc/gcc/diagnostic.c:879
#1  0x00000000009d76ad in simplify_subreg (outermode=HImode, 
    op=0x7ffff1d04f00, innermode=QImode, byte=0)
    at /export/gnu/import/git/gcc/gcc/simplify-rtx.c:5116
#2  0x00000000009d87e6 in simplify_gen_subreg (outermode=HImode, 
    op=0x7ffff1d04f00, innermode=QImode, byte=0)
    at /export/gnu/import/git/gcc/gcc/simplify-rtx.c:5426
#3  0x0000000000fcc60a in if_then_else_cond (x=0x7ffff1b6d390, 
    ptrue=0x7fffffffd448, pfalse=0x7fffffffd438)
    at /export/gnu/import/git/gcc/gcc/combine.c:8219
#4  0x0000000000fcbf66 in if_then_else_cond (x=0x7ffff1b6d3a8, 
    ptrue=0x7fffffffd4d0, pfalse=0x7fffffffd4c8)
    at /export/gnu/import/git/gcc/gcc/combine.c:8103
#5  0x0000000000fc305a in combine_simplify_rtx (x=0x7ffff1b6d3a8, 
    op0_mode=VOIDmode, in_dest=0)
    at /export/gnu/import/git/gcc/gcc/combine.c:4864
#6  0x0000000000fc2def in subst (x=0x7ffff1b6d3a8, from=0x7ffff1c170c0, 
    to=0x7ffff1c170c0, in_dest=0, unique_copy=0)
    at /export/gnu/import/git/gcc/gcc/combine.c:4803
#7  0x0000000000fc2ba7 in subst (x=0x7ffff1b64720, from=0x7ffff1c170c0, 
---Type <return> to continue, or q <return> to quit---
    to=0x7ffff1c170c0, in_dest=0, unique_copy=0)
    at /export/gnu/import/git/gcc/gcc/combine.c:4741
#8  0x0000000000fc2ba7 in subst (x=0x7ffff1b64738, from=0x7ffff1c170c0, 
    to=0x7ffff1c170c0, in_dest=0, unique_copy=0)
    at /export/gnu/import/git/gcc/gcc/combine.c:4741
#9  0x0000000000fbd20b in try_combine (i3=0x7ffff1b0a870, i2=0x7ffff1b0a798, 
    i1=0x0, new_direct_jump_p=0x7fffffffdaf4)
    at /export/gnu/import/git/gcc/gcc/combine.c:2885
#10 0x0000000000fb911e in combine_instructions (f=0x7ffff1c227c0, nregs=70)
    at /export/gnu/import/git/gcc/gcc/combine.c:1152
#11 0x0000000000fd898f in rest_of_handle_combine ()
    at /export/gnu/import/git/gcc/gcc/combine.c:13342


-- 

hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hjl dot tools at gmail dot
                   |                            |com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44695