On Tue, Aug 28, 2012 at 9:09 AM, Andrew Pinski <pins...@gmail.com> wrote: > On Mon, May 21, 2012 at 2:56 AM, Richard Guenther > <richard.guent...@gmail.com> wrote: >> On Sun, May 20, 2012 at 1:40 AM, Andrew Pinski <pins...@gmail.com> wrote: >>> The problem here is that tree-if-conv.c produces COND_EXPR instead of >>> the MAX/MIN EXPRs. When I added the expansion from COND_EXPR to >>> conditional moves, I assumes that the expressions which should have >>> been converted into MAX_EXPR/MIN_EXPR have already happened. >>> >>> This fixes the problem by having tree-if-conv fold the expression so >>> the MIN_EXPR/MAX_EXPR appears in the IR rather than COND_EXPR and the >>> expansion happens correctly to the min/max rtl rather than just >>> through the conditional move ones. >>> >>> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. >> >> As we are unconditionally building a gimple_assign from the folding result >> you need to re-gimplify it. The code was using build3 instead of fold_build3 >> to avoid that and to make sure we create a plain COND_EXPR we can >> later CSE / simplify properly. Generating a MAX_EXPR directly is certainly >> fine (can we always vectorize that?), but I suppose simply changing the >> code to use fold_build3 will have unwanted fallout (consider folds habit >> to insert conversions that are not requried on gimple). >> >> So I'd rather prefer to abstract the build3 (COND_EXPR,... into a >> helper function that uses fold_ternary and only if the result is an >> invariant/register or a MIN/MAX_EXPR use the result, canonicalizing >> it properly. > > Here is an updated patch which does exactly that. > > Note I noticed another regression dealing with my expansion for > COND_EXPR dealing with min/max and I will be submitting patches for > those issue tomorrow. > > OK? Bootstrap and tested on x86_64-linux-gnu.
Ok. Thanks, Richard. > Thanks, > Andrew Pinski > > ChangeLog: > * tree-if-conv.c (constant_or_ssa_name): New function. > (fold_build_cond_expr): New function. > (predicate_scalar_phi): Use fold_build_cond_expr instead of build3. > (predicate_mem_writes): Likewise.
