On November 14, 2015 9:49:28 AM GMT+01:00, Senthil Kumar Selvaraj <senthil_kumar.selva...@atmel.com> wrote: >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.
I didn't mean to suggest narrowing is not OK. In fact narrowing is always OK. Richard. >Richard? > >Regards >Senthil >> >> -- >> Marc Glisse
