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RFC patch for fold-const.c's fold_indirect_ref_1 / avoid type-checking ICE with TYPE_MIN_VALUE vs. offset signess mismatches
- From: Tobias Burnus <tobias dot burnus at physik dot fu-berlin dot de>
- To: gcc patches <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 10 May 2013 10:44:08 +0200
- Subject: RFC patch for fold-const.c's fold_indirect_ref_1 / avoid type-checking ICE with TYPE_MIN_VALUE vs. offset signess mismatches
I run into the following issue on the Fortran-Dev branch. I get an ICE due to a tree-checking assert for fold-const.c's fold_indirect_ref_1, which has
tree min_val = size_zero_node;
if (type_domain && TYPE_MIN_VALUE (type_domain))
min_val = TYPE_MIN_VALUE (type_domain);
op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01,
TYPE_SIZE_UNIT (type));
op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val);
The problem is that "op01" is unsigned (size_type_node) while "min_val" alias TYPE_MIN_VALUE is signed (gfc_array_index_type which is PTRDIFF_TYPE).
TYPE_MIN_VALUE gets set via tree.c's build_range_type_1, which has:
TYPE_MIN_VALUE (itype) = fold_convert (type, lowval);
TYPE_MAX_VALUE (itype) = highval ? fold_convert (type, highval) : NULL;
And "op01" becomes a size_type_node via tree.h's
fold_build_pointer_plus_loc (location_t loc, tree ptr, tree off)
{
return fold_build2_loc (loc, POINTER_PLUS_EXPR, TREE_TYPE (ptr),
ptr, fold_convert_loc (loc, sizetype, off));
I am not completely sure what's the best way to solve that, but the attached patch avoids the ICE for me.
I did an all-all language bootstrap (all,ada,go,objc,obj-c++) and had no new failures with regresting.
OK? Or do you have a better idea how to solve this?
Tobias
2013-05-10 Tobias Burnus <burnus@net-b.de>
* fold-const.c (fold_indirect_ref_1): Fold offset
to TREE_TYPE (min_val) before converting to array syntax.
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 74b451e..8ac873a 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -16591,10 +16591,11 @@ fold_indirect_ref_1 (location_t loc, tree type, tree op0)
tree min_val = size_zero_node;
if (type_domain && TYPE_MIN_VALUE (type_domain))
min_val = TYPE_MIN_VALUE (type_domain);
op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01,
TYPE_SIZE_UNIT (type));
+ op01 = fold_convert (TREE_TYPE (min_val), op01);
op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val);
return build4_loc (loc, ARRAY_REF, type, op00, op01,
NULL_TREE, NULL_TREE);
}
}