[PATCH] internal-fn: Convert uninitialized SSA_NAME into SCRATCH rtx[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. Here we add the condition "insn_operand_matches (icode, opno, scratch)" Then, we will only create scratch rtx that target allow scratch rtx in predicate. When the target doesn't allow scratch rtx in predicate, the later "else" condtion will create fresh pseudo for uninitialized SSA. I have verify it in RISC-V port and it works well. Bootstrap and Regression on X86 passed. Ok for trunk ? gcc/ChangeLog: * internal-fn.cc (expand_fn_using_insn): Convert uninitialized SSA into scratch. --- gcc/internal-fn.cc | 6 ++ 1 file changed, 6 insertions(+) diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc index 0fd34359247..fe4d86b3dbd 100644 --- a/gcc/internal-fn.cc +++ b/gcc/internal-fn.cc @@ -243,10 +243,16 @@ expand_fn_using_insn (gcall *stmt, insn_code icode, unsigned int noutputs, tree rhs = gimple_call_arg (stmt, i); tree rhs_type = TREE_TYPE (rhs); rtx rhs_rtx = expand_normal (rhs); + rtx scratch = gen_rtx_SCRATCH (TYPE_MODE (rhs_type)); if (INTEGRAL_TYPE_P (rhs_type)) 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)) + && insn_operand_matches (icode, opno, scratch)) + create_input_operand (&ops[opno], scratch, TYPE_MODE (rhs_type)); else create_input_operand (&ops[opno], rhs_rtx, TYPE_MODE (rhs_type)); opno += 1; -- 2.36.3
Re: [PATCH] internal-fn: Convert uninitialized SSA_NAME into SCRATCH rtx[PR110751]
Juzhe-Zhong writes: > 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. > > Here we add the condition "insn_operand_matches (icode, opno, scratch)" > Then, we will only create scratch rtx that target allow scratch rtx in > predicate. > When the target doesn't allow scratch rtx in predicate, the later "else" > condtion > will create fresh pseudo for uninitialized SSA. > > I have verify it in RISC-V port and it works well. > > Bootstrap and Regression on X86 passed. > > Ok for trunk ? > > gcc/ChangeLog: > > * internal-fn.cc (expand_fn_using_insn): Convert uninitialized SSA into > scratch. > > --- > gcc/internal-fn.cc | 6 ++ > 1 file changed, 6 insertions(+) > > diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc > index 0fd34359247..fe4d86b3dbd 100644 > --- a/gcc/internal-fn.cc > +++ b/gcc/internal-fn.cc > @@ -243,10 +243,16 @@ expand_fn_using_insn (gcall *stmt, insn_code icode, > unsigned int noutputs, >tree rhs = gimple_call_arg (stmt, i); >tree rhs_type = TREE_TYPE (rhs); >rtx rhs_rtx = expand_normal (rhs); > + rtx scratch = gen_rtx_SCRATCH (TYPE_MODE (rhs_type)); >if (INTEGRAL_TYPE_P (rhs_type)) > 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)) > +&& insn_operand_matches (icode, opno, scratch)) Rather than check insn_operand_matches here, I think we should create the scratch operand regardless and leave optabs.cc to deal with it. (This will need changes to optabs.cc.) How about adding: create_undefined_input_operand (expand_operand *op, machine_mode mode) that maps to a new EXPAND_UNDEFINED, then handle EXPAND_UNDEFINED in the two case statements in optabs.cc. Thanks, Richard > + create_input_operand (&ops[opno], scratch, TYPE_MODE (rhs_type)); >else > create_input_operand (&ops[opno], rhs_rtx, TYPE_MODE (rhs_type)); >opno += 1;
Re: Re: [PATCH] internal-fn: Convert uninitialized SSA_NAME into SCRATCH rtx[PR110751]
Thanks Richard. Address comment in V2: [PATCH V2] internal-fn: Support undefined rtx for uninitialized SSA_NAME (gnu.org) juzhe.zh...@rivai.ai From: Richard Sandiford Date: 2023-09-17 18:29 To: Juzhe-Zhong CC: gcc-patches; rguenther Subject: Re: [PATCH] internal-fn: Convert uninitialized SSA_NAME into SCRATCH rtx[PR110751] Juzhe-Zhong writes: > 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. > > Here we add the condition "insn_operand_matches (icode, opno, scratch)" > Then, we will only create scratch rtx that target allow scratch rtx in > predicate. > When the target doesn't allow scratch rtx in predicate, the later "else" > condtion > will create fresh pseudo for uninitialized SSA. > > I have verify it in RISC-V port and it works well. > > Bootstrap and Regression on X86 passed. > > Ok for trunk ? > > gcc/ChangeLog: > > * internal-fn.cc (expand_fn_using_insn): Convert uninitialized SSA into > scratch. > > --- > gcc/internal-fn.cc | 6 ++ > 1 file changed, 6 insertions(+) > > diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc > index 0fd34359247..fe4d86b3dbd 100644 > --- a/gcc/internal-fn.cc > +++ b/gcc/internal-fn.cc > @@ -243,10 +243,16 @@ expand_fn_using_insn (gcall *stmt, insn_code icode, > unsigned int noutputs, >tree rhs = gimple_call_arg (stmt, i); >tree rhs_type = TREE_TYPE (rhs); >rtx rhs_rtx = expand_normal (rhs); > + rtx scratch = gen_rtx_SCRATCH (TYPE_MODE (rhs_type)); >if (INTEGRAL_TYPE_P (rhs_type)) > 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)) > +&& insn_operand_matches (icode, opno, scratch)) Rather than check insn_operand_matches here, I think we should create the scratch operand regardless and leave optabs.cc to deal with it. (This will need changes to optabs.cc.) How about adding: create_undefined_input_operand (expand_operand *op, machine_mode mode) that maps to a new EXPAND_UNDEFINED, then handle EXPAND_UNDEFINED in the two case statements in optabs.cc. Thanks, Richard > + create_input_operand (&ops[opno], scratch, TYPE_MODE (rhs_type)); >else > create_input_operand (&ops[opno], rhs_rtx, TYPE_MODE (rhs_type)); >opno += 1;
