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i386.c (ix86_eax_live_at_start_p): New. 

* config/i386/i386.c (ix86_eax_live_at_start_p): New.
        (ix86_expand_prologue): Save and restore eax around stack probe
        if it's live.

From-SVN: r72933
This commit is contained in:
Richard Henderson 2003-10-25 12:42:39 -07:00 committed by Richard Henderson
parent e54918abd4
commit fe9f516f68
2 changed files with 39 additions and 5 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2003-10-25 Richard Henderson <rth@redhat.com>
* config/i386/i386.c (ix86_eax_live_at_start_p): New.
(ix86_expand_prologue): Save and restore eax around stack probe
if it's live.
2003-10-25 Jan Hubicka <jh@suse.cz> 2003-10-25 Jan Hubicka <jh@suse.cz>
* cppcharset.c (one_utf8_to_utf32): Initialize 's' to silence warning. * cppcharset.c (one_utf8_to_utf32): Initialize 's' to silence warning.

38
gcc/config/i386/i386.c
View File

@ -1705,6 +1705,22 @@ ix86_function_regparm (tree type, tree decl)
return regparm; return regparm;
} }
/* Return true if EAX is live at the start of the function. Used by
ix86_expand_prologue to determine if we need special help before
calling allocate_stack_worker. */
static bool
ix86_eax_live_at_start_p (void)
{
/* Cheat. Don't bother working forward from ix86_function_regparm
to the function type to whether an actual argument is located in
eax. Instead just look at cfg info, which is still close enough
to correct at this point. This gives false positives for broken
functions that might use uninitialized data that happens to be
allocated in eax, but who cares? */
return REGNO_REG_SET_P (ENTRY_BLOCK_PTR->global_live_at_end, 0);
}
/* Value is the number of bytes of arguments automatically /* Value is the number of bytes of arguments automatically
popped when returning from a subroutine call. popped when returning from a subroutine call.
FUNDECL is the declaration node of the function (as a tree), FUNDECL is the declaration node of the function (as a tree),
@ -5098,20 +5114,32 @@ ix86_expand_prologue (void)
} }
else else
{ {
/* Only valid for Win32 */ /* Only valid for Win32. */
rtx eax = gen_rtx_REG (SImode, 0);
const rtx eax = gen_rtx_REG (SImode, 0); bool eax_live = ix86_eax_live_at_start_p ();
rtx rtx_allocate = GEN_INT(allocate);
if (TARGET_64BIT) if (TARGET_64BIT)
abort (); abort ();
insn = emit_move_insn (eax, rtx_allocate); if (eax_live)
{
emit_insn (gen_push (eax));
allocate -= 4;
}
insn = emit_move_insn (eax, GEN_INT (allocate));
RTX_FRAME_RELATED_P (insn) = 1; RTX_FRAME_RELATED_P (insn) = 1;
insn = emit_insn (gen_allocate_stack_worker (eax)); insn = emit_insn (gen_allocate_stack_worker (eax));
RTX_FRAME_RELATED_P (insn) = 1; RTX_FRAME_RELATED_P (insn) = 1;
if (eax_live)
{
rtx t = plus_constant (stack_pointer_rtx, allocate);
emit_move_insn (eax, gen_rtx_MEM (SImode, t));
}
} }
if (frame.save_regs_using_mov && !TARGET_RED_ZONE) if (frame.save_regs_using_mov && !TARGET_RED_ZONE)
{ {
if (!frame_pointer_needed || !frame.to_allocate) if (!frame_pointer_needed || !frame.to_allocate)