[Bug rtl-optimization/49088] Combine fails to properly handle zero-extension and signed int constant

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49088

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> 2011-05-20 18:27:51 
UTC ---
(gdb) bt
#0  force_to_mode (x=0x7ffff0acbdf8, mode=DImode, mask=4294967294, 
    just_select=0) at /export/gnu/import/git/gcc-x32/gcc/combine.c:8154
#1  0x0000000001121405 in simplify_and_const_int_1 (mode=DImode, 
    varop=0x7ffff0acbdf8, constop=4294967294)
    at /export/gnu/import/git/gcc-x32/gcc/combine.c:9413
#2  0x00000000011216e4 in simplify_and_const_int (x=0x0, mode=DImode, 
    varop=0x7ffff0acbdf8, constop=4294967294)
    at /export/gnu/import/git/gcc-x32/gcc/combine.c:9511
#3  0x0000000001123c57 in simplify_shift_const_1 (code=LSHIFTRT, 
    result_mode=DImode, varop=0x7ffff0acbdf8, orig_count=32)
    at /export/gnu/import/git/gcc-x32/gcc/combine.c:10568
#4  0x0000000001123d45 in simplify_shift_const (x=0x0, code=LSHIFTRT, 
    result_mode=DImode, varop=0x7ffff0acbe10, count=32)
    at /export/gnu/import/git/gcc-x32/gcc/combine.c:10599
#5  0x000000000111a923 in expand_compound_operation (x=0x7ffff0c4ddb0)
    at /export/gnu/import/git/gcc-x32/gcc/combine.c:6916
(gdb) f 5
#5  0x000000000111a923 in expand_compound_operation (x=0x7ffff0c4ddb0)
    at /export/gnu/import/git/gcc-x32/gcc/combine.c:6916
6916          tem = simplify_shift_const (NULL_RTX, unsignedp ? LSHIFTRT :
ASHIFTRT,
(gdb) call debug_rtx (x)
(zero_extend:DI (plus:SI (subreg:SI (reg/f:DI 20 frame) 0)
        (const_int -58 [0xffffffffffffffc6])))
(gdb)