On Sat, Nov 14, 2015 at 09:13:41AM +0100, Marc Glisse wrote: > On Sat, 14 Nov 2015, Senthil Kumar Selvaraj wrote: > > >This patch came out of a discussion held in the gcc mailing list > >(https://gcc.gnu.org/ml/gcc/2015-11/msg00067.html). > > > >The patch restricts folding of conditional exprs with lhs previously > >set by a type conversion to occur only if the source of the type > >conversion's mode is word mode or smaller. > > > >Bootstrapped and reg tested on x86_64 (with --enable-languages=c,c++). > > > >If ok, could you commit please? I don't have commit access. > > > >Regards > >Senthil > > > >gcc/ChangeLog > > > >2015-11-11 Senthil Kumar Selvaraj <senthil_kumar.selva...@atmel.com> > > > > * tree-vrp.c (simplify_cond_using_ranges): Fold only > > if innerop's mode is word_mode or smaller. > > > > > >diff --git gcc/tree-vrp.c gcc/tree-vrp.c > >index e2393e4..c139bc6 100644 > >--- gcc/tree-vrp.c > >+++ gcc/tree-vrp.c > >@@ -9467,6 +9467,8 @@ simplify_cond_using_ranges (gcond *stmt) > > innerop = gimple_assign_rhs1 (def_stmt); > > > > if (TREE_CODE (innerop) == SSA_NAME > >+ && (GET_MODE_SIZE(TYPE_MODE(TREE_TYPE(innerop))) > >+ <= GET_MODE_SIZE(word_mode)) > > && !POINTER_TYPE_P (TREE_TYPE (innerop))) > > { > > value_range *vr = get_value_range (innerop); > > I thought the result of the discussion was that the transformation is ok if > either it is narrowing or it widens but to something no bigger than > word_mode. So you should have 2 comparisons, or 1 with a max.
Hmm, I came to the opposite conclusion - I thought Richard only okayed "widening upto word-mode", not the narrowing. Richard? Regards Senthil > > -- > Marc Glisse
