Re: ifcvt buglet

[Michael Meissner <meissner at cygnus dot com>]

On Wed, May 31, 2000 at 01:23:13AM -0600, Jeffrey A Law wrote:
> The PA was failing to bootstrap because it mis-compiled 
> file_name_nondirectory in the C++ front-end.  This mis-compilation
> showed up as a compile-time failure when building the C++ runtime
> libraries.
> 
> Basically we had a conditional jump in parallel with a reg->reg copy.
> if-conversion removed the conditional jump & reg->reg copy.  This
> resulted in an uninitialized pseudo and ultimately incorrect code.
> 
> if/condexec conversion doesn't know how to deal with jumps which have
> additional side effects.  This patch (suggested by Richard) fixes the
> problem.
> 
> 
> 	* ifcvt.c (cond_exec_process_if_block): Do nothing if the last insn
> 	in the block is more than just a simple conditional branch.
> 	(noce_process_if_block): Similarly.

Hmmm, I may need to have a clobber in the jumps I want to convert to
conditional code for the port that I'm working on.  I would prefer a test that
allowed clobbers (but not moves).

-- 
Michael Meissner, Cygnus Solutions, a Red Hat company.
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