Hello All:
This new version of patch 4 use improve ree pass for rs6000 target using
defined ABI interfaces.
Bootstrapped and regtested on power64-linux-gnu.
Thanks & Regards
Ajit
ree: Improve ree pass for rs6000 target using defined abi interfaces
For rs6000 target we see redundant zero and sign
extension and done to improve ree pass to eliminate
such redundant zero and sign extension using defines
ABI interfaces.
2023-04-22 Ajit Kumar Agarwal <aagar...@linux.ibm.com>
gcc/ChangeLog:
* ree.cc (combline_reaching_defs): Add zero_extend
using defined abi interfaces.
(add_removable_extension): use of defined abi interfaces
for no reaching defs.
(abi_extension_candidate_return_reg_p): New defined ABI function.
(abi_extension_candidate_p): New defined ABI function.
(abi_extension_candidate_argno_p): New defined ABI function.
(abi_handle_regs_without_defs_p): New defined ABI function.
gcc/testsuite/ChangeLog:
* g++.target/powerpc/zext-elim-3.C
---
gcc/ree.cc | 176 +++++++++++++++---
.../g++.target/powerpc/zext-elim-3.C | 16 ++
2 files changed, 162 insertions(+), 30 deletions(-)
create mode 100644 gcc/testsuite/g++.target/powerpc/zext-elim-3.C
diff --git a/gcc/ree.cc b/gcc/ree.cc
index 413aec7c8eb..0de96b1ece1 100644
--- a/gcc/ree.cc
+++ b/gcc/ree.cc
@@ -473,7 +473,8 @@ get_defs (rtx_insn *insn, rtx reg, vec<rtx_insn *> *dest)
break;
}
- gcc_assert (use != NULL);
+ if (use == NULL)
+ return NULL;
ref_chain = DF_REF_CHAIN (use);
@@ -514,7 +515,8 @@ get_uses (rtx_insn *insn, rtx reg)
if (REGNO (DF_REF_REG (def)) == REGNO (reg))
break;
- gcc_assert (def != NULL);
+ if (def == NULL)
+ return NULL;
ref_chain = DF_REF_CHAIN (def);
@@ -750,6 +752,103 @@ get_extended_src_reg (rtx src)
return src;
}
+/* Return TRUE if the candidate insn is zero extend and regno is
+ an return registers. */
+
+static bool
+abi_extension_candidate_return_reg_p (rtx_insn *insn, int regno)
+{
+ rtx set = single_set (insn);
+
+ if (GET_CODE (SET_SRC (set)) != ZERO_EXTEND)
+ return false;
+
+ if (FUNCTION_VALUE_REGNO_P (regno))
+ return true;
+
+ return false;
+}
+
+/* Return TRUE if reg source operand of zero_extend is argument registers
+ and not return registers and source and destination operand are same
+ and mode of source and destination operand are not same. */
+
+static bool
+abi_extension_candidate_p (rtx_insn *insn)
+{
+ rtx set = single_set (insn);
+
+ if (GET_CODE (SET_SRC (set)) != ZERO_EXTEND)
+ return false;
+
+ machine_mode ext_dst_mode = GET_MODE (SET_DEST (set));
+ rtx orig_src = XEXP (SET_SRC (set),0);
+
+ bool copy_needed
+ = (REGNO (SET_DEST (set)) != REGNO (XEXP (SET_SRC (set), 0)));
+
+ if (!copy_needed && ext_dst_mode != GET_MODE (orig_src)
+ && FUNCTION_ARG_REGNO_P (REGNO (orig_src))
+ && !abi_extension_candidate_return_reg_p (insn, REGNO (orig_src)))
+ return true;
+
+ return false;
+}
+
+/* Return TRUE if the candidate insn is zero extend and regno is
+ an argument registers. */
+
+static bool
+abi_extension_candidate_argno_p (rtx_code code, int regno)
+{
+ if (code != ZERO_EXTEND)
+ return false;
+
+ if (FUNCTION_ARG_REGNO_P (regno))
+ return true;
+
+ return false;
+}
+
+/* Return TRUE if the candidate insn doesn't have defs and have
+ * uses without RTX_BIN_ARITH/RTX_COMM_ARITH/RTX_UNARY rtx class. */
+
+static bool
+abi_handle_regs_without_defs_p (rtx_insn *insn)
+{
+ if (side_effects_p (PATTERN (insn)))
+ return false;
+
+ struct df_link *uses
+ = get_uses (insn, SET_DEST (PATTERN (insn)));
+
+ if (!uses)
+ return false;
+
+ for (df_link *use = uses; use; use = use->next)
+ {
+ if (!use->ref)
+ return false;
+
+ if (BLOCK_FOR_INSN (insn)
+ != BLOCK_FOR_INSN (DF_REF_INSN (use->ref)))
+ return false;
+
+ rtx_insn *use_insn = DF_REF_INSN (use->ref);
+
+ if (GET_CODE (PATTERN (use_insn)) == SET)
+ {
+ rtx_code code = GET_CODE (SET_SRC (PATTERN (use_insn)));
+
+ if (GET_RTX_CLASS (code) == RTX_BIN_ARITH
+ || GET_RTX_CLASS (code) == RTX_COMM_ARITH
+ || GET_RTX_CLASS (code) == RTX_UNARY)
+ return false;
+ }
+ }
+ return true;
+}
+
/* This function goes through all reaching defs of the source
of the candidate for elimination (CAND) and tries to combine
the extension with the definition instruction. The changes
@@ -770,6 +869,11 @@ combine_reaching_defs (ext_cand *cand, const_rtx set_pat,
ext_state *state)
state->defs_list.truncate (0);
state->copies_list.truncate (0);
+ rtx orig_src = XEXP (SET_SRC (cand->expr),0);
+
+ if (abi_extension_candidate_p (cand->insn)
+ && (!get_defs (cand->insn, orig_src, NULL)))
+ return abi_handle_regs_without_defs_p (cand->insn);
outcome = make_defs_and_copies_lists (cand->insn, set_pat, state);
@@ -1112,26 +1216,34 @@ add_removable_extension (const_rtx expr, rtx_insn *insn,
rtx reg = XEXP (src, 0);
struct df_link *defs, *def;
ext_cand *cand;
+ defs = get_defs (insn, reg, NULL);
/* Zero-extension of an undefined value is partly defined (it's
completely undefined for sign-extension, though). So if there exists
a path from the entry to this zero-extension that leaves this register
uninitialized, removing the extension could change the behavior of
correct programs. So first, check it is not the case. */
- if (code == ZERO_EXTEND && !bitmap_bit_p (init_regs, REGNO (reg)))
+ if (!defs && abi_extension_candidate_argno_p (code, REGNO (reg)))
{
- if (dump_file)
- {
- fprintf (dump_file, "Cannot eliminate extension:\n");
- print_rtl_single (dump_file, insn);
- fprintf (dump_file, " because it can operate on uninitialized"
- " data\n");
- }
+ ext_cand e = {expr, code, mode, insn};
+ insn_list->safe_push (e);
return;
}
+ if ((code == ZERO_EXTEND
+ && !bitmap_bit_p (init_regs, REGNO (reg))))
+ {
+ if (dump_file)
+ {
+ fprintf (dump_file, "Cannot eliminate extension:\n");
+ print_rtl_single (dump_file, insn);
+ fprintf (dump_file, " because it can operate on uninitialized"
+ " data\n");
+ }
+ return;
+ }
+
/* Second, make sure we can get all the reaching definitions. */
- defs = get_defs (insn, reg, NULL);
if (!defs)
{
if (dump_file)
@@ -1321,7 +1433,8 @@ find_and_remove_re (void)
&& (REGNO (SET_DEST (set)) != REGNO (XEXP (SET_SRC (set), 0))))
{
reinsn_copy_list.safe_push (curr_cand->insn);
- reinsn_copy_list.safe_push (state.defs_list[0]);
+ if (state.defs_list.length() != 0)
+ reinsn_copy_list.safe_push (state.defs_list[0]);
}
reinsn_del_list.safe_push (curr_cand->insn);
state.modified[INSN_UID (curr_cand->insn)].deleted = 1;
@@ -1342,24 +1455,27 @@ find_and_remove_re (void)
Remember that the memory reference will be changed to refer to the
destination of the extention. So we're actually emitting a copy
from the new destination to the old destination. */
- for (unsigned int i = 0; i < reinsn_copy_list.length (); i += 2)
- {
- rtx_insn *curr_insn = reinsn_copy_list[i];
- rtx_insn *def_insn = reinsn_copy_list[i + 1];
-
- /* Use the mode of the destination of the defining insn
- for the mode of the copy. This is necessary if the
- defining insn was used to eliminate a second extension
- that was wider than the first. */
- rtx sub_rtx = *get_sub_rtx (def_insn);
- rtx set = single_set (curr_insn);
- rtx new_dst = gen_rtx_REG (GET_MODE (SET_DEST (sub_rtx)),
- REGNO (XEXP (SET_SRC (set), 0)));
- rtx new_src = gen_rtx_REG (GET_MODE (SET_DEST (sub_rtx)),
- REGNO (SET_DEST (set)));
- rtx new_set = gen_rtx_SET (new_dst, new_src);
- emit_insn_after (new_set, def_insn);
- }
+ for (unsigned int i = 0; i < reinsn_copy_list.length (); i += 2)
+ {
+ rtx_insn *curr_insn = reinsn_copy_list[i];
+
+ if ((i+1) < reinsn_copy_list.length())
+ {
+ rtx_insn *def_insn = reinsn_copy_list[i + 1];
+ /* Use the mode of the destination of the defining insn
+ for the mode of the copy. This is necessary if the
+ defining insn was used to eliminate a second extension
+ that was wider than the first. */
+ rtx sub_rtx = *get_sub_rtx (def_insn);
+ rtx set = single_set (curr_insn);
+ rtx new_dst = gen_rtx_REG (GET_MODE (SET_DEST (sub_rtx)),
+ REGNO (XEXP (SET_SRC (set), 0)));
+ rtx new_src = gen_rtx_REG (GET_MODE (SET_DEST (sub_rtx)),
+ REGNO (SET_DEST (set)));
+ rtx new_set = gen_rtx_SET (new_dst, new_src);
+ emit_insn_after (new_set, def_insn);
+ }
+ }
/* Delete all useless extensions here in one sweep. */
FOR_EACH_VEC_ELT (reinsn_del_list, i, curr_insn)
diff --git a/gcc/testsuite/g++.target/powerpc/zext-elim-3.C
b/gcc/testsuite/g++.target/powerpc/zext-elim-3.C
new file mode 100644
index 00000000000..1d443af066a
--- /dev/null
+++ b/gcc/testsuite/g++.target/powerpc/zext-elim-3.C
@@ -0,0 +1,16 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target powerpc_p9vector_ok } */
+/* { dg-options "-mcpu=power9 -O2 -free" } */
+
+void *memset(void *b, int c, unsigned long len)
+{
+ unsigned long i;
+
+ for (i = 0; i < len; i++)
+ ((unsigned char *)b)[i] = c;
+
+ return b;
+}
+
+/* { dg-final { scan-assembler-not "rlwinm" } } */
--
2.31.1
