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Re: [tree-ssa] COND_EXPR lowering.
- From: Richard Henderson <rth at redhat dot com>
- To: Andrew MacLeod <amacleod at redhat dot com>
- Cc: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>, gcc-patches <gcc-patches at gcc dot gnu dot org>, Jeff Law <law at redhat dot com>
- Date: Fri, 24 Oct 2003 14:38:24 -0700
- Subject: Re: [tree-ssa] COND_EXPR lowering.
- References: <1067001734.14404.2805.camel@p4>
[ Coming in late here, but... ]
On Fri, Oct 24, 2003 at 09:22:12AM -0400, Andrew MacLeod wrote:
> Since stmt_last and bsi_last do the same thing, and under some
> circumstance can be expensive, I'd suggest using bsi_last() in
> cleanup_control_flow() instead of last_stmt, and passing the BSI into
> cleanup_cond_expr_graph () avoiding the second call.
Let's do what's cleanest here. We'll shortly have O(1) access
to the end of the basic block.
> The only other thing that I think Diego agreed with (yes? no?) is that
> we probably ought to set the BB for the 2 goto's on the arms of the
> COND_EXPR. Yeah, they aren't real stmt's, but there is no reason someone
> couldn't look at them as real stmts.. ie, someone doing path following
> may want to process the 2 arms exactly like they process a GOTO, so we
> ought to make them behave like a GOTO stmt for consistancy, so we ought
> to set their BB.
I'd rather think of them as a 2-ary multi-way branch. I.e.
one indivisible statement. So having the gotos in different
blocks doesn't make sense.
r~