https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102285
--- Comment #20 from rguenther at suse dot de <rguenther at suse dot de> --- On Fri, 1 Oct 2021, qinzhao at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102285 > > --- Comment #18 from qinzhao at gcc dot gnu.org --- > (In reply to Richard Biener from comment #13) > > We could try sth like the following which should cover this testcase and > > also hopefully doesn't break anything else. > > > > diff --git a/gcc/expr.c b/gcc/expr.c > > index e0bcbccd905..ab3b5b26c20 100644 > > --- a/gcc/expr.c > > +++ b/gcc/expr.c > > @@ -5322,7 +5322,7 @@ non_mem_decl_p (tree base) > > /* Returns true if REF refers to an object that does not > > reside in memory and has non-BLKmode. */ > > > > -static inline bool > > +bool > > mem_ref_refers_to_non_mem_p (tree ref) > > { > > tree base; > > diff --git a/gcc/expr.h b/gcc/expr.h > > index 94a85b40dca..85650e96834 100644 > > --- a/gcc/expr.h > > +++ b/gcc/expr.h > > @@ -346,4 +346,6 @@ extern void expand_operands (tree, tree, rtx, rtx*, > > rtx*, > > /* Return an rtx for the size in bytes of the value of an expr. */ > > extern rtx expr_size (tree); > > > > +extern bool mem_ref_refers_to_non_mem_p (tree ref); > > + > > #endif /* GCC_EXPR_H */ > > diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c > > index 8312d08aab2..c1d23dfd21e 100644 > > --- a/gcc/internal-fn.c > > +++ b/gcc/internal-fn.c > > @@ -3015,8 +3015,10 @@ expand_DEFERRED_INIT (internal_fn, gcall *stmt) > > reg_lhs = true; > > else > > { > > - rtx tem = expand_expr (lhs, NULL_RTX, VOIDmode, EXPAND_WRITE); > > - reg_lhs = !MEM_P (tem); > > + tree lhs_base = lhs; > > + while (handled_component_p (lhs_base)) > > + lhs_base = TREE_OPERAND (lhs_base, 0); > > + reg_lhs = mem_refers_to_non_mem_p (lhs_base); > > } > > > > if (!reg_lhs) > > I tried the above patch, it even doesn't work for this testing case. > After the patch, this call to .DEFERRED_INIT will be expanded through REG > path, > however, the existing problem in the LHS IR broke the "expand_assignment" > too. > so I see. > , I still think that the root cause is the IR for LHS of the following call > to .DEFERRED_INIT is not correct: > > MEM[(int[0:D.1993] *)&fb.3] = .DEFERRED_INIT (16, 2, 1); > > the LHS is: MEM[(int[0:D.1993] *)&fb.3] > > this is the MEM_REF, whose base address is a ADDR_EXPR of a VAR_DECL, however, > this VAR_DECL is not addressable, will be in REG. this is conflicting: how can > a variable that in a REG be address taken? It doesn't have its address taken - the ADDR_EXPR is artificial when at the base of a MEM_REF. Let me thake this bug then.
