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| author | Mark Mitchell <mark@markmitchell.com> | 1998-07-05 23:33:36 +0000 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 1998-07-05 17:33:36 -0600 |
| commit | 9de2c71a47cdd2531c359d20c839c1a0b6cccfe6 (patch) | |
| tree | 817f057be0d30d722b3e39eb6880d25dffc2c751 /gcc/cse.c | |
| parent | adc05e6ce6c535b2dcc218e0486dd6298f5c7ba8 (diff) | |
| download | gcc-9de2c71a47cdd2531c359d20c839c1a0b6cccfe6.zip gcc-9de2c71a47cdd2531c359d20c839c1a0b6cccfe6.tar.gz gcc-9de2c71a47cdd2531c359d20c839c1a0b6cccfe6.tar.bz2 | |
cse.c (cse_insn): When SETting (MEM (ADDRESSOF (X))) to Y...
* cse.c (cse_insn): When SETting (MEM (ADDRESSOF (X))) to Y,
don't claim that the former is equivalent to the latter.
From-SVN: r20935
Diffstat (limited to 'gcc/cse.c')
| -rw-r--r-- | gcc/cse.c | 15 |
1 files changed, 13 insertions, 2 deletions
@@ -7405,6 +7405,7 @@ cse_insn (insn, in_libcall_block) if (sets[i].rtl) { register rtx dest = SET_DEST (sets[i].rtl); + rtx inner_dest = sets[i].inner_dest; register struct table_elt *elt; /* Don't record value if we are not supposed to risk allocating @@ -7453,8 +7454,18 @@ cse_insn (insn, in_libcall_block) sets[i].dest_hash = HASH (dest, GET_MODE (dest)); } - elt = insert (dest, sets[i].src_elt, - sets[i].dest_hash, GET_MODE (dest)); + if (GET_CODE (inner_dest) == MEM + && GET_CODE (XEXP (inner_dest, 0)) == ADDRESSOF) + /* Given (SET (MEM (ADDRESSOF (X))) Y) we don't want to say + that (MEM (ADDRESSOF (X))) is equivalent to Y. + Consider the case in which the address of the MEM is + passed to a function, which alters the MEM. Then, if we + later use Y instead of the MEM we'll miss the update. */ + elt = insert (dest, 0, sets[i].dest_hash, GET_MODE (dest)); + else + elt = insert (dest, sets[i].src_elt, + sets[i].dest_hash, GET_MODE (dest)); + elt->in_memory = (GET_CODE (sets[i].inner_dest) == MEM && (! RTX_UNCHANGING_P (sets[i].inner_dest) || FIXED_BASE_PLUS_P (XEXP (sets[i].inner_dest, |