File nvl425798-1.patch of Package gcc43
2008-04-30 Alan Modra <amodra@bigpond.net.au>
* config/rs6000/rs6000.c (ALWAYS_RESTORE_ALTIVEC_BEFORE_POP): Define.
(rs6000_emit_epilogue): Use backchain to restore only when we
have a large frame. Make use of frame pointer to restore if we
have one. Handle ALWAYS_RESTORE_ALTIVEC_BEFORE_POP.
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c.orig 2009-11-20 13:51:55.000000000 +0100
+++ gcc/config/rs6000/rs6000.c 2009-11-20 13:51:57.000000000 +0100
@@ -1,6 +1,6 @@
/* Subroutines used for code generation on IBM RS/6000.
Copyright (C) 1991, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
+ 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
Free Software Foundation, Inc.
Contributed by Richard Kenner (kenner@vlsi1.ultra.nyu.edu)
@@ -16281,6 +16281,10 @@ rs6000_output_function_prologue (FILE *f
rs6000_pic_labelno++;
}
+/* Non-zero if vmx regs are restored before the frame pop, zero if
+ we restore after the pop when possible. */
+#define ALWAYS_RESTORE_ALTIVEC_BEFORE_POP 0
+
/* Emit function epilogue as insns.
At present, dwarf2out_frame_debug_expr doesn't understand
@@ -16320,9 +16324,14 @@ rs6000_emit_epilogue (int sibcall)
|| current_function_calls_eh_return
|| info->first_fp_reg_save == 64
|| FP_SAVE_INLINE (info->first_fp_reg_save));
- use_backchain_to_restore_sp = (frame_pointer_needed
- || current_function_calls_alloca
- || info->total_size > 32767);
+ /* Restore via the backchain when we have a large frame, since this
+ is more efficient than an addis, addi pair. The second condition
+ here will not trigger at the moment; We don't actually need a
+ frame pointer for alloca, but the generic parts of the compiler
+ give us one anyway. */
+ use_backchain_to_restore_sp = (info->total_size > 32767
+ || (cfun->calls_alloca
+ && !frame_pointer_needed));
using_mtcr_multiple = (rs6000_cpu == PROCESSOR_PPC601
|| rs6000_cpu == PROCESSOR_PPC603
|| rs6000_cpu == PROCESSOR_PPC750
@@ -16427,8 +16436,9 @@ rs6000_emit_epilogue (int sibcall)
stack. */
if (TARGET_ALTIVEC_ABI
&& info->altivec_size != 0
- && DEFAULT_ABI != ABI_V4
- && info->altivec_save_offset < (TARGET_32BIT ? -220 : -288))
+ && (ALWAYS_RESTORE_ALTIVEC_BEFORE_POP
+ || (DEFAULT_ABI != ABI_V4
+ && info->altivec_save_offset < (TARGET_32BIT ? -220 : -288))))
{
int i;
@@ -16439,6 +16449,8 @@ rs6000_emit_epilogue (int sibcall)
gen_rtx_MEM (Pmode, sp_reg_rtx));
sp_offset = 0;
}
+ else if (frame_pointer_needed)
+ frame_reg_rtx = hard_frame_pointer_rtx;
for (i = info->first_altivec_reg_save; i <= LAST_ALTIVEC_REGNO; ++i)
if (info->vrsave_mask & ALTIVEC_REG_BIT (i))
@@ -16463,18 +16475,23 @@ rs6000_emit_epilogue (int sibcall)
if (TARGET_ALTIVEC
&& TARGET_ALTIVEC_VRSAVE
&& info->vrsave_mask != 0
- && DEFAULT_ABI != ABI_V4
- && info->vrsave_save_offset < (TARGET_32BIT ? -220 : -288))
+ && (ALWAYS_RESTORE_ALTIVEC_BEFORE_POP
+ || (DEFAULT_ABI != ABI_V4
+ && info->vrsave_save_offset < (TARGET_32BIT ? -220 : -288))))
{
rtx addr, mem, reg;
- if (use_backchain_to_restore_sp
- && frame_reg_rtx == sp_reg_rtx)
+ if (frame_reg_rtx == sp_reg_rtx)
{
- frame_reg_rtx = gen_rtx_REG (Pmode, 11);
- emit_move_insn (frame_reg_rtx,
- gen_rtx_MEM (Pmode, sp_reg_rtx));
- sp_offset = 0;
+ if (use_backchain_to_restore_sp)
+ {
+ frame_reg_rtx = gen_rtx_REG (Pmode, 11);
+ emit_move_insn (frame_reg_rtx,
+ gen_rtx_MEM (Pmode, sp_reg_rtx));
+ sp_offset = 0;
+ }
+ else if (frame_pointer_needed)
+ frame_reg_rtx = hard_frame_pointer_rtx;
}
addr = gen_rtx_PLUS (Pmode, frame_reg_rtx,
@@ -16486,17 +16503,11 @@ rs6000_emit_epilogue (int sibcall)
emit_insn (generate_set_vrsave (reg, info, 1));
}
- /* If we have a frame pointer, a call to alloca, or a large stack
- frame, restore the old stack pointer using the backchain. Otherwise,
- we know what size to update it with. */
+ /* If we have a large stack frame, restore the old stack pointer
+ using the backchain. */
if (use_backchain_to_restore_sp)
{
- if (frame_reg_rtx != sp_reg_rtx)
- {
- emit_move_insn (sp_reg_rtx, frame_reg_rtx);
- frame_reg_rtx = sp_reg_rtx;
- }
- else
+ if (frame_reg_rtx == sp_reg_rtx)
{
/* Under V.4, don't reset the stack pointer until after we're done
loading the saved registers. */
@@ -16507,6 +16518,30 @@ rs6000_emit_epilogue (int sibcall)
gen_rtx_MEM (Pmode, sp_reg_rtx));
sp_offset = 0;
}
+ else if (ALWAYS_RESTORE_ALTIVEC_BEFORE_POP
+ && DEFAULT_ABI == ABI_V4)
+ /* frame_reg_rtx has been set up by the altivec restore. */
+ ;
+ else
+ {
+ emit_move_insn (sp_reg_rtx, frame_reg_rtx);
+ frame_reg_rtx = sp_reg_rtx;
+ }
+ }
+ /* If we have a frame pointer, we can restore the old stack pointer
+ from it. */
+ else if (frame_pointer_needed)
+ {
+ frame_reg_rtx = sp_reg_rtx;
+ if (DEFAULT_ABI == ABI_V4)
+ frame_reg_rtx = gen_rtx_REG (Pmode, 11);
+
+ emit_insn (TARGET_32BIT
+ ? gen_addsi3 (frame_reg_rtx, hard_frame_pointer_rtx,
+ GEN_INT (info->total_size))
+ : gen_adddi3 (frame_reg_rtx, hard_frame_pointer_rtx,
+ GEN_INT (info->total_size)));
+ sp_offset = 0;
}
else if (info->push_p
&& DEFAULT_ABI != ABI_V4
@@ -16521,7 +16556,8 @@ rs6000_emit_epilogue (int sibcall)
}
/* Restore AltiVec registers if we have not done so already. */
- if (TARGET_ALTIVEC_ABI
+ if (!ALWAYS_RESTORE_ALTIVEC_BEFORE_POP
+ && TARGET_ALTIVEC_ABI
&& info->altivec_size != 0
&& (DEFAULT_ABI == ABI_V4
|| info->altivec_save_offset >= (TARGET_32BIT ? -220 : -288)))
@@ -16548,7 +16584,8 @@ rs6000_emit_epilogue (int sibcall)
}
/* Restore VRSAVE if we have not done so already. */
- if (TARGET_ALTIVEC
+ if (!ALWAYS_RESTORE_ALTIVEC_BEFORE_POP
+ && TARGET_ALTIVEC
&& TARGET_ALTIVEC_VRSAVE
&& info->vrsave_mask != 0
&& (DEFAULT_ABI == ABI_V4
