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| author | Dale Johannesen <dalej@apple.com> | 2004-06-16 17:13:34 +0000 |
|---|---|---|
| committer | Dale Johannesen <dalej@gcc.gnu.org> | 2004-06-16 17:13:34 +0000 |
| commit | d85428e234930c9d1352d1e5494b5b245dcd1a22 (patch) | |
| tree | eac12c2a50a19fa9cba5bc97d3201615d9aeb226 /gcc/loop.c | |
| parent | e370de6e30762a5fb49cd39832c6ed98a60bd82b (diff) | |
| download | gcc-d85428e234930c9d1352d1e5494b5b245dcd1a22.zip gcc-d85428e234930c9d1352d1e5494b5b245dcd1a22.tar.gz gcc-d85428e234930c9d1352d1e5494b5b245dcd1a22.tar.bz2 | |
loop.c (loop_givs_reduce): Avoid miscompilation of loops entered at bottom.
2004-06-16 Dale Johannesen <dalej@apple.com>
* loop.c (loop_givs_reduce): Avoid miscompilation of
loops entered at bottom.
From-SVN: r83248
Diffstat (limited to 'gcc/loop.c')
| -rw-r--r-- | gcc/loop.c | 13 |
1 files changed, 12 insertions, 1 deletions
@@ -4699,13 +4699,24 @@ loop_givs_reduce (struct loop *loop, struct iv_class *bl) this is an address giv, then try to put the increment immediately after its use, so that flow can create an auto-increment addressing mode. */ + /* Don't do this for loops entered at the bottom, to avoid + this invalid transformation: + jmp L; -> jmp L; + TOP: TOP: + use giv use giv + L: inc giv + inc biv L: + test biv test giv + cbr TOP cbr TOP + */ if (v->giv_type == DEST_ADDR && bl->biv_count == 1 && bl->biv->always_executed && ! bl->biv->maybe_multiple /* We don't handle reversed biv's because bl->biv->insn does not have a valid INSN_LUID. */ && ! bl->reversed && v->always_executed && ! v->maybe_multiple - && INSN_UID (v->insn) < max_uid_for_loop) + && INSN_UID (v->insn) < max_uid_for_loop + && !loop->top) { /* If other giv's have been combined with this one, then this will work only if all uses of the other giv's occur |