On 09/22/2015 06:03 AM, Jason Merrill wrote:
A simple fix would be to just disable the reference games when we're looking at a hard register variable. That would break decltype(auto) for hard register variables, but since they are a GNU extension that isn't a big deal.
Like so. Tested x86_64-pc-linux-gnu, applying to trunk.
commit a5e9d513231728c3c52d956311fb9e5f06097184 Author: Jason Merrill <ja...@redhat.com> Date: Thu Jul 30 14:55:57 2015 -0400 PR c++/67064 * semantics.c (force_paren_expr): Don't mess with hard register vars. diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c index 8796b17..c0a8b32 100644 --- a/gcc/cp/semantics.c +++ b/gcc/cp/semantics.c @@ -1660,6 +1660,8 @@ force_paren_expr (tree expr) REF_PARENTHESIZED_P (expr) = true; else if (type_dependent_expression_p (expr)) expr = build1 (PAREN_EXPR, TREE_TYPE (expr), expr); + else if (VAR_P (expr) && DECL_HARD_REGISTER (expr)) + /* We can't bind a hard register variable to a reference. */; else { cp_lvalue_kind kind = lvalue_kind (expr); diff --git a/gcc/testsuite/g++.dg/parse/parens3.C b/gcc/testsuite/g++.dg/parse/parens3.C new file mode 100644 index 0000000..afb392b --- /dev/null +++ b/gcc/testsuite/g++.dg/parse/parens3.C @@ -0,0 +1,18 @@ +// PR c++/67064 +// { dg-options "-w" } + +struct s { + int i; +}; + +register struct s *reg __asm__( "1" ); + +int f(void) +{ + int i; + + i = reg->i; + i = (reg)->i; + + return i; +}