| Message ID | 20130522151105.GF23266@virgil.suse |
|---|---|
| State | New |
| Headers | show |
> earlier this week I asked on IRC whether we could have non-top-level > BIT_FIELD_REFs and Richi said that we could. However, when I later > looked at SRA code, quite apparently it is not designed to handle > non-top-level BIT_FIELD_REFs, IMAGPART_EXPRs or REALPART_EXPRs. So in > order to test whether that assumption is OK, I added the following > into the gimple verifier and ran bootstrap and testsuite of all > languages including Ada and ObjC++ on x86_64. It survived, which > makes me wondering whether we do not want it in trunk. This looks plausible to me, but I think that you ought to verify the real assumption instead, which is that the type of the 3 nodes is always scalar. The non-toplevelness of the nodes is merely a consequence of this property.
On Thu, 23 May 2013, Eric Botcazou wrote: > > earlier this week I asked on IRC whether we could have non-top-level > > BIT_FIELD_REFs and Richi said that we could. However, when I later > > looked at SRA code, quite apparently it is not designed to handle > > non-top-level BIT_FIELD_REFs, IMAGPART_EXPRs or REALPART_EXPRs. So in > > order to test whether that assumption is OK, I added the following > > into the gimple verifier and ran bootstrap and testsuite of all > > languages including Ada and ObjC++ on x86_64. It survived, which > > makes me wondering whether we do not want it in trunk. > > This looks plausible to me, but I think that you ought to verify the real > assumption instead, which is that the type of the 3 nodes is always scalar. > The non-toplevelness of the nodes is merely a consequence of this property. Yeah. But please put the verification into tree-cfg.c:verify_expr instead. Thanks, Richard.
Index: src/gcc/tree-cfg.c =================================================================== --- src.orig/gcc/tree-cfg.c +++ src/gcc/tree-cfg.c @@ -2858,6 +2858,8 @@ verify_types_in_gimple_min_lval (tree ex static bool verify_types_in_gimple_reference (tree expr, bool require_lvalue) { + bool top_level = true; + while (handled_component_p (expr)) { tree op = TREE_OPERAND (expr, 0); @@ -2944,6 +2946,17 @@ verify_types_in_gimple_reference (tree e return false; } + if (!top_level + && (TREE_CODE (expr) == BIT_FIELD_REF + || TREE_CODE (expr) == IMAGPART_EXPR + || TREE_CODE (expr) == REALPART_EXPR)) + { + error ("non-top-level BIT_FIELD_REF, IMAGPART_EXPR or REALPART_EXPR"); + debug_generic_stmt (expr); + return true; + } + + top_level = false; expr = op; }