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[PATCH] rs6000: Some rs6000_emit_epilogue improvements
- From: Segher Boessenkool <segher at kernel dot crashing dot org>
- To: gcc-patches at gcc dot gnu dot org
- Cc: dje dot gcc at gmail dot com, Segher Boessenkool <segher at kernel dot crashing dot org>
- Date: Fri, 17 May 2019 22:08:12 +0000
- Subject: [PATCH] rs6000: Some rs6000_emit_epilogue improvements
This uses epilogue_type directly. It also changes some ints to bools,
declares variables later, and simplifies some code.
There is one actual change:
else if (info->push_p
&& DEFAULT_ABI != ABI_V4
- && !crtl->calls_eh_return)
+ && epilogue_type != EPILOGUE_TYPE_EH_RETURN)
{
/* Prevent reordering memory accesses against stack pointer restore. */
(different because calls_eh_return can be true for sibcalls). This is
a bugfix. The code was never exercised.
One place in the epilogue still uses crtl->calls_eh_return. If that
is changed the prologue has to have a corresponding change, and the
emit_prologue function does not have an epilogue_type parameter, so
bail on changing this for now. We might want to do this (saving the
CR fields to separate stack slots) always, not just for functions
calling eh_return, but that will require more investigation.
Tested on powerpc64-linux ({-m32,-m64}, p7) and on powerpc64le-linux
(p9); committing to trunk.
Segher
2019-05-17 Segher Boessenkool <segher@kernel.crashing.org>
* config/rs6000/rs6000.c (restore_saved_cr): Change a boolean
argument to be type bool (was int before).
(rs6000_emit_epilogue): Simplify some code. Declare some variables
at first use. Use type bool for some variables. Fix a theoretical
eh_return bug for svr4.
---
gcc/config/rs6000/rs6000.c | 97 +++++++++++++++++++++++++---------------------
1 file changed, 53 insertions(+), 44 deletions(-)
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 2992ba5..da7dae1 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -27712,7 +27712,7 @@ load_cr_save (int regno, rtx frame_reg_rtx, int offset, bool exit_func)
/* Reload CR from REG. */
static void
-restore_saved_cr (rtx reg, int using_mfcr_multiple, bool exit_func)
+restore_saved_cr (rtx reg, bool using_mfcr_multiple, bool exit_func)
{
int count = 0;
int i;
@@ -27876,15 +27876,6 @@ emit_cfa_restores (rtx cfa_restores)
void
rs6000_emit_epilogue (enum epilogue_type epilogue_type)
{
- int sibcall = (epilogue_type == EPILOGUE_TYPE_SIBCALL);
- rs6000_stack_t *info;
- int restoring_GPRs_inline;
- int restoring_FPRs_inline;
- int using_load_multiple;
- int using_mtcr_multiple;
- int use_backchain_to_restore_sp;
- int restore_lr;
- int strategy;
HOST_WIDE_INT frame_off = 0;
rtx sp_reg_rtx = gen_rtx_REG (Pmode, 1);
rtx frame_reg_rtx = sp_reg_rtx;
@@ -27896,30 +27887,38 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
machine_mode fp_reg_mode = TARGET_HARD_FLOAT ? DFmode : SFmode;
int fp_reg_size = 8;
int i;
- bool exit_func;
unsigned ptr_regno;
- info = rs6000_stack_info ();
+ rs6000_stack_t *info = rs6000_stack_info ();
+
+ if (epilogue_type == EPILOGUE_TYPE_NORMAL && crtl->calls_eh_return)
+ epilogue_type = EPILOGUE_TYPE_EH_RETURN;
+
+ int strategy = info->savres_strategy;
+ bool using_load_multiple = !!(strategy & REST_MULTIPLE);
+ bool restoring_GPRs_inline = !!(strategy & REST_INLINE_GPRS);
+ bool restoring_FPRs_inline = !!(strategy & REST_INLINE_FPRS);
+ if (epilogue_type == EPILOGUE_TYPE_SIBCALL)
+ {
+ restoring_GPRs_inline = true;
+ restoring_FPRs_inline = true;
+ }
+
+ bool using_mtcr_multiple = (rs6000_tune == PROCESSOR_PPC601
+ || rs6000_tune == PROCESSOR_PPC603
+ || rs6000_tune == PROCESSOR_PPC750
+ || optimize_size);
- strategy = info->savres_strategy;
- using_load_multiple = strategy & REST_MULTIPLE;
- restoring_FPRs_inline = sibcall || (strategy & REST_INLINE_FPRS);
- restoring_GPRs_inline = sibcall || (strategy & REST_INLINE_GPRS);
- using_mtcr_multiple = (rs6000_tune == PROCESSOR_PPC601
- || rs6000_tune == PROCESSOR_PPC603
- || rs6000_tune == PROCESSOR_PPC750
- || optimize_size);
/* 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 + (info->lr_save_p
- ? info->lr_save_offset
- : 0) > 32767
- || (cfun->calls_alloca
- && !frame_pointer_needed));
- restore_lr = (info->lr_save_p
+ bool use_backchain_to_restore_sp
+ = (info->total_size + (info->lr_save_p ? info->lr_save_offset : 0) > 32767
+ || (cfun->calls_alloca && !frame_pointer_needed));
+
+ bool restore_lr = (info->lr_save_p
&& (restoring_FPRs_inline
|| (strategy & REST_NOINLINE_FPRS_DOESNT_RESTORE_LR))
&& (restoring_GPRs_inline
@@ -27929,10 +27928,7 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
if (WORLD_SAVE_P (info))
{
- int i, j;
- char rname[30];
- const char *alloc_rname;
- rtvec p;
+ gcc_assert (epilogue_type != EPILOGUE_TYPE_SIBCALL);
/* eh_rest_world_r10 will return to the location saved in the LR
stack slot (which is not likely to be our caller.)
@@ -27941,19 +27937,31 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
The exception-handling stuff that was here in 2.95 is no
longer necessary. */
+ rtvec p;
p = rtvec_alloc (9
+ 32 - info->first_gp_reg_save
+ LAST_ALTIVEC_REGNO + 1 - info->first_altivec_reg_save
+ 63 + 1 - info->first_fp_reg_save);
- strcpy (rname, ((crtl->calls_eh_return) ?
- "*eh_rest_world_r10" : "*rest_world"));
- alloc_rname = ggc_strdup (rname);
+ const char *rname;
+ switch (epilogue_type)
+ {
+ case EPILOGUE_TYPE_NORMAL:
+ rname = ggc_strdup ("*rest_world");
+ break;
- j = 0;
+ case EPILOGUE_TYPE_EH_RETURN:
+ rname = ggc_strdup ("*eh_rest_world_r10");
+ break;
+
+ default:
+ gcc_unreachable ();
+ }
+
+ int j = 0;
RTVEC_ELT (p, j++) = ret_rtx;
RTVEC_ELT (p, j++)
- = gen_rtx_USE (VOIDmode, gen_rtx_SYMBOL_REF (Pmode, alloc_rname));
+ = gen_rtx_USE (VOIDmode, gen_rtx_SYMBOL_REF (Pmode, rname));
/* The instruction pattern requires a clobber here;
it is shared with the restVEC helper. */
RTVEC_ELT (p, j++) = gen_hard_reg_clobber (Pmode, 11);
@@ -27972,6 +27980,7 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
}
}
+ int i;
for (i = 0; i < 32 - info->first_gp_reg_save; i++)
{
rtx reg = gen_rtx_REG (reg_mode, info->first_gp_reg_save + i);
@@ -28196,7 +28205,7 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
}
else if (info->push_p
&& DEFAULT_ABI != ABI_V4
- && !crtl->calls_eh_return)
+ && epilogue_type != EPILOGUE_TYPE_EH_RETURN)
{
/* Prevent reordering memory accesses against stack pointer restore. */
if (cfun->calls_alloca
@@ -28356,9 +28365,9 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
function will deallocate the stack, so we don't need to worry
about the unwinder restoring cr from an invalid stack frame
location. */
- exit_func = (!restoring_FPRs_inline
- || (!restoring_GPRs_inline
- && info->first_fp_reg_save == 64));
+ bool exit_func = (!restoring_FPRs_inline
+ || (!restoring_GPRs_inline
+ && info->first_fp_reg_save == 64));
/* In the ELFv2 ABI we need to restore all call-saved CR fields from
*separate* slots if the routine calls __builtin_eh_return, so
@@ -28424,7 +28433,7 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
restore_saved_lr (0, exit_func);
/* Load exception handler data registers, if needed. */
- if (!sibcall && crtl->calls_eh_return)
+ if (epilogue_type == EPILOGUE_TYPE_EH_RETURN)
{
unsigned int i, regno;
@@ -28615,13 +28624,13 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
RTX_FRAME_RELATED_P (insn) = 1;
}
- if (!sibcall && crtl->calls_eh_return)
+ if (epilogue_type == EPILOGUE_TYPE_EH_RETURN)
{
rtx sa = EH_RETURN_STACKADJ_RTX;
emit_insn (gen_add3_insn (sp_reg_rtx, sp_reg_rtx, sa));
}
- if (!sibcall && restoring_FPRs_inline)
+ if (epilogue_type != EPILOGUE_TYPE_SIBCALL && restoring_FPRs_inline)
{
if (cfa_restores)
{
@@ -28646,7 +28655,7 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
emit_jump_insn (targetm.gen_simple_return ());
}
- if (!sibcall && !restoring_FPRs_inline)
+ if (epilogue_type != EPILOGUE_TYPE_SIBCALL && !restoring_FPRs_inline)
{
bool lr = (strategy & REST_NOINLINE_FPRS_DOESNT_RESTORE_LR) == 0;
rtvec p = rtvec_alloc (3 + !!lr + 64 - info->first_fp_reg_save);
@@ -28685,7 +28694,7 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
if (cfa_restores)
{
- if (sibcall)
+ if (epilogue_type == EPILOGUE_TYPE_SIBCALL)
/* Ensure the cfa_restores are hung off an insn that won't
be reordered above other restores. */
emit_insn (gen_blockage ());
--
1.8.3.1