@@ -514,7 +514,8 @@ 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 +751,117 @@ get_extended_src_reg (rtx src)
return src;
}
+/* Return TRUE if target mode is equal to source mode, false otherwise. */
+
+static bool
+abi_target_promote_function_mode (machine_mode mode)
+{
+ int unsignedp;
+ machine_mode tgt_mode
+ = targetm.calls.promote_function_mode (NULL_TREE, mode, &unsignedp,
+ NULL_TREE, 1);
+
+ if (tgt_mode == mode)
+ return true;
+ else
+ return false;
+}
+
+/* Return TRUE if regno is a return register. */
+
+static inline bool
+abi_extension_candidate_return_reg_p (int regno)
+{
+ return targetm.calls.function_value_regno_p (regno);
+}
+
+/* Return TRUE if the following conditions are satisified.
+
+ a) reg source operand is argument register and not return register.
+ b) mode of source and destination operand are different.
+ c) if not promoted REGNO of source and destination operand are same. */
+
+static bool
+abi_extension_candidate_p (rtx_insn *insn)
+{
+ rtx set = single_set (insn);
+ machine_mode dst_mode = GET_MODE (SET_DEST (set));
+ rtx orig_src = XEXP (SET_SRC (set), 0);
+
+ if (!FUNCTION_ARG_REGNO_P (REGNO (orig_src))
+ || abi_extension_candidate_return_reg_p (/*insn,*/ REGNO (orig_src)))
+ return false;
+
+ /* Return FALSE if mode of destination and source is same. */
+ if (dst_mode == GET_MODE (orig_src))
+ return false;
+
+ machine_mode mode = GET_MODE (XEXP (SET_SRC (set), 0));
+ bool promote_p = abi_target_promote_function_mode (mode);
+
+ /* Return FALSE if promote is false and REGNO of source and destination
+ is different. */
+ if (!promote_p && REGNO (SET_DEST (set)) != REGNO (orig_src))
+ return false;
+
+ return true;
+}
+
+/* Return TRUE if regno is an argument register. */
+
+static inline bool
+abi_extension_candidate_argno_p (int regno)
+{
+ return FUNCTION_ARG_REGNO_P (regno);
+}
+
+/* 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 (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;
+ }
+ }
+
+ rtx set = single_set (insn);
+
+ if (GET_CODE (SET_SRC (set)) == SIGN_EXTEND)
+ {
+ machine_mode mode = GET_MODE (XEXP (SET_SRC (set), 0));
+ bool promote_p = abi_target_promote_function_mode (mode);
+
+ return promote_p;
+ }
+ 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 +882,11 @@ 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 (cand->insn);
outcome = make_defs_and_copies_lists (cand->insn, set_pat, state);
@@ -1116,9 +1233,12 @@ add_removable_extension (const_rtx expr, rtx_insn *insn,
/* 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)))
+ uninitialized and not argument register, 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))
+ && !abi_extension_candidate_argno_p (REGNO (reg)))
{
if (dump_file)
{
@@ -1130,10 +1250,17 @@ add_removable_extension (const_rtx expr, rtx_insn *insn,
return;
}
- /* Second, make sure we can get all the reaching definitions. */
+ /* Second, make sure we can get all the reaching definitions or reg is
+ argument register. */
defs = get_defs (insn, reg, NULL);
if (!defs)
{
+ if (abi_extension_candidate_argno_p (REGNO (reg)))
+ {
+ ext_cand e = {expr, code, mode, insn};
+ insn_list->safe_push (e);
+ return;
+ }
if (dump_file)
{
fprintf (dump_file, "Cannot eliminate extension:\n");
@@ -1321,7 +1448,8 @@ 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;
@@ -1345,6 +1473,10 @@ find_and_remove_re (void)
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 ())
+ continue;
+
rtx_insn *def_insn = reinsn_copy_list[i + 1];
/* Use the mode of the destination of the defining insn
new file mode 100644
@@ -0,0 +1,13 @@
+/* { dg-options "-mcpu=power9 -O2" } */
+
+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 "\mrlwinm\M" } } */
Hello Vineet, Jeff and Bernhard: This version 11 of the patch uses abi interfaces to remove zero and sign extension elimination. Bootstrapped and regtested on powerpc-linux-gnu. In this version (version 11) of the patch following review comments are incorporated. a) Removal of hard code zero_extend and sign_extend in abi interfaces. b) Source and destination with different registers are considered. c) Further enhancements. d) Added sign extension elimination using abi interfaces. d) Addressed remaining review comments from Vineet. e) Addressed review comments from Bernhard. Please check if its addressed bootstrapped failure with RISC-V. Also please let me know if there is anything missing in this patch. Ok for trunk? Thanks & Regards Ajit ree: Improve ree pass 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 defined ABI interfaces. 2023-10-23 Ajit Kumar Agarwal <aagarwa1@linux.ibm.com> gcc/ChangeLog: * ree.cc (combine_reaching_defs): Use of zero_extend and sign_extend defined abi interfaces. (add_removable_extension): Use of defined abi interfaces for no reaching defs. (abi_extension_candidate_return_reg_p): New function. (abi_extension_candidate_p): New function. (abi_extension_candidate_argno_p): New function. (abi_handle_regs): New function. (abi_target_promote_function_mode): New function. gcc/testsuite/ChangeLog: * g++.target/powerpc/zext-elim-3.C --- gcc/ree.cc | 144 +++++++++++++++++- .../g++.target/powerpc/zext-elim-3.C | 13 ++ 2 files changed, 151 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/g++.target/powerpc/zext-elim-3.C