| Message ID | CAFiYyc0_nvt+GAXmK8RX++XCjqvudaZtsK97XrtK3qiK+B8taA@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On 02/09/15 06:42, Richard Biener wrote: > On Mon, Feb 9, 2015 at 8:15 AM, Jeff Law <law@redhat.com> wrote: >> On 02/03/15 04:39, Richard Biener wrote: >>>> >>>> I found that explicit types were ignored in some cases. It was >>>> frustrating to say the least. >>> >>> >>> Huh, that would be a bug. Do you have a pattern where that happens? >> >> I'll have to recreate them. In the mean time consider something else I'm >> playing with that causes an odd error from genmatch... >> >> /* If we have a narrowing conversion of an arithmetic or logical >> operation where both are operands widening conversions from the >> same type as the outer narrowing conversion. Then convert the >> innermost operands to a suitable unsigned type (to avoid introducing >> undefined behaviour), perform the operation and convert the result to >> the desired type. */ >> (simplify >> (convert (plus (convert@2 @0) (convert @1))) >> (if (TREE_TYPE (@0) == TREE_TYPE (@1) >> && TREE_TYPE (@0) == type >> && INTEGRAL_TYPE_P (type) >> && TYPE_PRECISION (TREE_TYPE (@2)) >= TYPE_PRECISION (TREE_TYPE >> (@0))) >> (with { tree utype = unsigned_type_for (TREE_TYPE (@0));} >> (convert (plus (convert:utype @0) (convert:utype @1))))))) >> >> So given two narrow operands that get widened, added, and the final result >> narrowed back down to the original operand types. Replace with convert the >> operands to an unsigned type (of same size as the operand), operate on them >> and convert to the final desired type. >> >> This happens to fix 47477 (P2 regression). Works perfectly for the >> testcase. >> >> >> Of course we'd like to extend that to other operators... So, adding the >> obvious for iterator... >> >> (for op (plus minus) >> (simplify >> (convert (op (convert@2 @0) (convert @1))) >> (if (TREE_TYPE (@0) == TREE_TYPE (@1) >> && TREE_TYPE (@0) == type >> && INTEGRAL_TYPE_P (type) >> && TYPE_PRECISION (TREE_TYPE (@2)) >= TYPE_PRECISION (TREE_TYPE >> (@0))) >> (with { tree utype = unsigned_type_for (TREE_TYPE (@0));} >> (convert (op (convert:utype @0) (convert:utype @1))))))) >> >> >> Which causes genmatch to barf: >> >> build/genmatch --gimple /home/gcc/GIT-2/gcc/gcc/match.pd \ >> > tmp-gimple-match.c >> genmatch: two conversions in a row >> >> >> Not only does genmatch barf, it doesn't give any indication what part of the >> .pd file it found objectionable. > > Yeah, I'll have to assign locations to more places at some point. > > But the following fixes your testcase, committed to trunk as obvious. > > Richard. > > 2015-02-09 Richard Biener <rguenther@suse.de> > > * genmatch.c (replace_id): Copy expr_type. Cool, thanks! jeff
Index: gcc/genmatch.c =================================================================== --- gcc/genmatch.c (revision 220540) +++ gcc/genmatch.c (working copy) @@ -982,6 +982,7 @@ replace_id (operand *o, user_id *id, id_ { expr *ne = new expr (e->operation == id ? with : e->operation, e->is_commutative); + ne->expr_type = e->expr_type; for (unsigned i = 0; i < e->ops.length (); ++i) ne->append_op (replace_id (e->ops[i], id, with)); return ne;