[Bug target/56560] [4.6/4.7 regression] vzeroupper clobbers argument with AVX

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56560



--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> 2013-03-08 17:21:18 
UTC ---

The caller info is lost by



(gdb) bt

#0  init_cumulative_args (cum=0x7fffffffc3f0, fntype=0x7ffff1472e70, 

    libname=0x0, fndecl=0x0, caller=1)

    at /export/gnu/import/git/gcc-release/gcc/config/i386/i386.c:5562

#1  0x0000000000640011 in block_move_libcall_safe_for_call_parm ()

    at /export/gnu/import/git/gcc-release/gcc/expr.c:1244

#2  0x000000000063fc07 in emit_block_move_hints (x=0x7ffff1470780, 

    y=0x7ffff1470750, size=0x7ffff133a530, method=BLOCK_OP_CALL_PARM, 

    expected_align=0, expected_size=-1)

    at /export/gnu/import/git/gcc-release/gcc/expr.c:1139

#3  0x000000000063ff3c in emit_block_move (x=0x7ffff1470780, y=0x7ffff1470750, 

    size=0x7ffff133a530, method=BLOCK_OP_CALL_PARM)

    at /export/gnu/import/git/gcc-release/gcc/expr.c:1206

#4  0x000000000064693a in emit_push_insn (x=0x7ffff1470750, mode=BLKmode, 

    type=0x7ffff1472690, size=0x7ffff133a530, align=64, partial=0, reg=0x0, 

    extra=4, args_addr=0x7ffff1334560, args_so_far=0x7ffff133a470, 

    reg_parm_stack_space=0, alignment_pad=0x7ffff133a470)

    at /export/gnu/import/git/gcc-release/gcc/expr.c:4116

#5  0x000000000056d1ad in store_one_arg (arg=0x7fffffffc760, 

    argblock=0x7ffff1334560, flags=0, variable_size=0, reg_parm_stack_space=0)

    at /export/gnu/import/git/gcc-release/gcc/calls.c:4646

#6  0x0000000000568b51 in expand_call (exp=0x7ffff1333cb0, 

    target=0x7ffff1461f00, ignore=0)

    at /export/gnu/import/git/gcc-release/gcc/calls.c:3023



when storing struct S on stack.  This patch:



diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c

index c1f6c88..8005207 100644

--- a/gcc/config/i386/i386.c

+++ b/gcc/config/i386/i386.c

@@ -5562,7 +5562,7 @@ init_cumulative_args (CUMULATIVE_ARGS *cum,  /* Argument

info to initialize */

   memset (cum, 0, sizeof (*cum));



   /* Initialize for the current callee.  */

-  if (caller)

+  if (caller && fndecl)

     {

       cfun->machine->callee_pass_avx256_p = false;

       cfun->machine->callee_return_avx256_p = false;



fixes it.