> -----Original Message----- > From: H.J. Lu <[email protected]> > Sent: Saturday, August 8, 2026 6:57 AM > To: Hongtao Liu <[email protected]> > Cc: GCC Patches <[email protected]>; Uros Bizjak > <[email protected]>; Liu, Hongtao <[email protected]> > Subject: [GCC 16, PATCH] x86: Check DECL_INCOMING_RTL for argument > passing check > > On Tue, Aug 4, 2026 at 3:02 PM H.J. Lu <[email protected]> wrote: > > > > On Tue, Aug 4, 2026 at 2:40 PM Hongtao Liu <[email protected]> wrote: > > > > > > On Sun, Aug 2, 2026 at 2:34 PM H.J. Lu <[email protected]> wrote: > > > > > > > > On Sat, Aug 1, 2026 at 4:49 PM Uros Bizjak <[email protected]> wrote: > > > > > > > > > > On Sat, Aug 1, 2026 at 5:12 AM H.J. Lu <[email protected]> wrote: > > > > > > > > > > > > When checking if a register argument is used as local > > > > > > variable, also return true if non-local variable is the source > > > > > > of the argument-linked memory store. > > > > > > > > > > > > gcc/ > > > > > > > > > > > > PR target/126529 > > > > > > * config/i386/i386.cc (ix86_spill_register_argument_p): Also > > > > > > check non-local variable source for the argument-linked memory > > > > > > store. > > > > > > > > > > > > gcc/testsuite/ > > > > > > > > > > > > PR target/126529 > > > > > > * gcc.target/i386/pr126529.c: New test. > > > > > > > > > > This is the third patch in the same area, so it IMO points to a > > > > > more systematic issue. Please find someone else that is able to > > > > > thoroughly review the patch (and the core issue that lies behind > > > > > these problems) from the generic middle-end side of the compiler. > > > > > > > > > > Uros. > > > > > > > > Here is the v2 patch to check the argument's DECL_INCOMING_RTL > > > > instead. > > > > > > /* Return true if OP is passed in memory. */ > > > return MEM_P (DECL_INCOMING_RTL (var)); > > > > > > DECL_INCOMING_RTL mean param_decl in stack, callee can also take the > > > parameter as local variable and put it in it's own stack, but looks > > > like at assign_stack_local have already handled that case, and here > > > in ix86_find_max_used_stack_alignment it just raise the requirement, > > > not lower that. So it seems ok. > > > Better to add more explanation in the comment. > > > Also to be defensive, avoid NULL for DECL_INCOMING_RTL (var), change it > to > > > return DECL_INCOMING_RTL (var) && MEM_P (DECL_INCOMING_RTL > (var)); > > > ? > > > > Here is the patch I am checking in. I copied DECL_INCOMING_RTL > > comments from tree.h: > > > > static bool > > ix86_argument_passed_on_stack_p (const_rtx op) { > > tree mem_expr = MEM_EXPR (op); > > if (!mem_expr) > > return false; > > > > tree var = get_base_address (mem_expr); > > if (TREE_CODE (var) != PARM_DECL) > > return false; > > > > /* For PARM_DECL, DECL_INCOMING_RTL holds an RTL for the stack slot > > or register where the data was actually passed. Return true if > > OP is passed in memory. */ > > return DECL_INCOMING_RTL (var) && MEM_P (DECL_INCOMING_RTL > (var)); } > > > > > Others LGTM. > > OK for backport to GCC 16?
Ok. > > Thanks. > > -- > H.J.
