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| author | Juzhe-Zhong <juzhe.zhong@rivai.ai> | 2023-09-20 22:58:49 +0800 |
|---|---|---|
| committer | Robin Dapp <rdapp@ventanamicro.com> | 2023-09-20 18:27:08 +0200 |
| commit | 27282dc0931484c31fa391772499d878afcc746a (patch) | |
| tree | 00f8ac0e91c22bb4c105172dc283def4104ef363 | |
| parent | 75c4b0cde4835b45350da0a5cd82f1d1a0a7a2f1 (diff) | |
| download | gcc-27282dc0931484c31fa391772499d878afcc746a.zip gcc-27282dc0931484c31fa391772499d878afcc746a.tar.gz gcc-27282dc0931484c31fa391772499d878afcc746a.tar.bz2 | |
internal-fn: Support undefined rtx for uninitialized SSA_NAME[PR110751]
According to PR: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110751
As Richard and Richi suggested, we recognize uninitialized SSA_NAME and convert it
into SCRATCH rtx if the target predicate allows SCRATCH.
It can help to reduce redundant data move instructions of targets like RISC-V.
Bootstrap and Regression on x86 passed.
gcc/ChangeLog:
PR target/110751
* internal-fn.cc (expand_fn_using_insn): Support undefined rtx value.
* optabs.cc (maybe_legitimize_operand): Ditto.
(can_reuse_operands_p): Ditto.
* optabs.h (enum expand_operand_type): Ditto.
(create_undefined_input_operand): Ditto.
| -rw-r--r-- | gcc/internal-fn.cc | 4 | ||||
| -rw-r--r-- | gcc/optabs.cc | 13 | ||||
| -rw-r--r-- | gcc/optabs.h | 13 |
3 files changed, 28 insertions, 2 deletions
diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc index 0fd3435..61d5a9e 100644 --- a/gcc/internal-fn.cc +++ b/gcc/internal-fn.cc @@ -247,6 +247,10 @@ expand_fn_using_insn (gcall *stmt, insn_code icode, unsigned int noutputs, create_convert_operand_from (&ops[opno], rhs_rtx, TYPE_MODE (rhs_type), TYPE_UNSIGNED (rhs_type)); + else if (TREE_CODE (rhs) == SSA_NAME + && SSA_NAME_IS_DEFAULT_DEF (rhs) + && VAR_P (SSA_NAME_VAR (rhs))) + create_undefined_input_operand (&ops[opno], TYPE_MODE (rhs_type)); else create_input_operand (&ops[opno], rhs_rtx, TYPE_MODE (rhs_type)); opno += 1; diff --git a/gcc/optabs.cc b/gcc/optabs.cc index 32ff379..8b96f23 100644 --- a/gcc/optabs.cc +++ b/gcc/optabs.cc @@ -8102,6 +8102,16 @@ maybe_legitimize_operand (enum insn_code icode, unsigned int opno, goto input; } break; + + case EXPAND_UNDEFINED_INPUT: + /* See if the predicate accepts a SCRATCH rtx, which in this context + indicates an undefined value. Use an uninitialized register if not. */ + if (!insn_operand_matches (icode, opno, op->value)) + { + op->value = gen_reg_rtx (op->mode); + goto input; + } + return true; } return insn_operand_matches (icode, opno, op->value); } @@ -8140,7 +8150,8 @@ can_reuse_operands_p (enum insn_code icode, switch (op1->type) { case EXPAND_OUTPUT: - /* Outputs must remain distinct. */ + case EXPAND_UNDEFINED_INPUT: + /* Outputs and undefined intputs must remain distinct. */ return false; case EXPAND_FIXED: diff --git a/gcc/optabs.h b/gcc/optabs.h index c80b7f4..9b78d40 100644 --- a/gcc/optabs.h +++ b/gcc/optabs.h @@ -37,7 +37,8 @@ enum expand_operand_type { EXPAND_CONVERT_TO, EXPAND_CONVERT_FROM, EXPAND_ADDRESS, - EXPAND_INTEGER + EXPAND_INTEGER, + EXPAND_UNDEFINED_INPUT }; /* Information about an operand for instruction expansion. */ @@ -117,6 +118,16 @@ create_input_operand (class expand_operand *op, rtx value, create_expand_operand (op, EXPAND_INPUT, value, mode, false); } +/* Make OP describe an undefined input operand of mode MODE. MODE cannot + be null. */ + +inline void +create_undefined_input_operand (class expand_operand *op, machine_mode mode) +{ + create_expand_operand (op, EXPAND_UNDEFINED_INPUT, gen_rtx_SCRATCH (mode), + mode, false); +} + /* Like create_input_operand, except that VALUE must first be converted to mode MODE. UNSIGNED_P says whether VALUE is unsigned. */ |