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* [PATCH v2] LoongArch: Implement FCCmode reload and cstore<ANYF:mode>4
@ 2023-12-15  8:57 Xi Ruoyao
  2023-12-22  6:36 ` Jiahao Xu
  0 siblings, 1 reply; 2+ messages in thread
From: Xi Ruoyao @ 2023-12-15  8:57 UTC (permalink / raw)
  To: gcc-patches; +Cc: chenglulu, i, xuchenghua, Jiahao Xu, Xi Ruoyao

We used a branch to load floating-point comparison results into GPR.
This is very slow when the branch is not predictable.

Implement movfcc so we can reload FCCmode into GPRs, FPRs, and MEM.
Then implement cstore<ANYF:mode>4.

gcc/ChangeLog:

	* config/loongarch/loongarch-tune.h
	(loongarch_rtx_cost_data::movcf2gr): New field.
	(loongarch_rtx_cost_data::movcf2gr_): New method.
	(loongarch_rtx_cost_data::use_movcf2gr): New method.
	* config/loongarch/loongarch-def.cc
	(loongarch_rtx_cost_data::loongarch_rtx_cost_data): Set movcf2gr
	to COSTS_N_INSNS (7) and movgr2cf to COSTS_N_INSNS (15), based
	on timing on LA464.
	(loongarch_cpu_rtx_cost_data): Set movcf2gr and movgr2cf to
	COSTS_N_INSNS (1) for LA664.
	(loongarch_rtx_cost_optimize_size): Set movcf2gr and movgr2cf to
	COSTS_N_INSNS (1) + 1.
	* config/loongarch/predicates.md (loongarch_fcmp_operator): New
	predicate.
	* config/loongarch/loongarch.md (movfcc): Change to
	define_expand.
	(movfcc_internal): New define_insn.
	(fcc_to_<X:mode>): New define_insn.
	(cstore<ANYF:mode>4): New define_expand.
	* config/loongarch/loongarch.cc
	(loongarch_hard_regno_mode_ok_uncached): Allow FCCmode in GPRs
	and GPRs.
	(loongarch_secondary_reload): Reload FCCmode via FPR and/or GPR.
	(loongarch_emit_float_compare): Call gen_reg_rtx instead of
	loongarch_allocate_fcc.
	(loongarch_allocate_fcc): Remove.
	(loongarch_move_to_gpr_cost): Handle FCC_REGS -> GR_REGS.
	(loongarch_move_from_gpr_cost): Handle GR_REGS -> FCC_REGS.
	(loongarch_register_move_cost): Handle FCC_REGS -> FCC_REGS,
	FCC_REGS -> FP_REGS, and FP_REGS -> FCC_REGS.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/movcf2gr.c: New test.
	* gcc.target/loongarch/movcf2gr-via-fr.c: New test.
---

Superseds
https://gcc.gnu.org/pipermail/gcc-patches/2023-December/640497.html.

Bootstrapped and regtested on loongarch64-linux-gnu.  Ok for trunk?

 gcc/config/loongarch/loongarch-def.cc         | 13 +++-
 gcc/config/loongarch/loongarch-tune.h         | 15 +++-
 gcc/config/loongarch/loongarch.cc             | 70 ++++++++++++-------
 gcc/config/loongarch/loongarch.md             | 69 ++++++++++++++++--
 gcc/config/loongarch/predicates.md            |  4 ++
 .../gcc.target/loongarch/movcf2gr-via-fr.c    | 10 +++
 gcc/testsuite/gcc.target/loongarch/movcf2gr.c |  9 +++
 7 files changed, 157 insertions(+), 33 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/loongarch/movcf2gr-via-fr.c
 create mode 100644 gcc/testsuite/gcc.target/loongarch/movcf2gr.c

diff --git a/gcc/config/loongarch/loongarch-def.cc b/gcc/config/loongarch/loongarch-def.cc
index 4a8885e8343..843be78e46e 100644
--- a/gcc/config/loongarch/loongarch-def.cc
+++ b/gcc/config/loongarch/loongarch-def.cc
@@ -101,15 +101,21 @@ loongarch_rtx_cost_data::loongarch_rtx_cost_data ()
     int_mult_di (COSTS_N_INSNS (4)),
     int_div_si (COSTS_N_INSNS (5)),
     int_div_di (COSTS_N_INSNS (5)),
+    movcf2gr (COSTS_N_INSNS (7)),
+    movgr2cf (COSTS_N_INSNS (15)),
     branch_cost (6),
     memory_latency (4) {}
 
 /* The following properties cannot be looked up directly using "cpucfg".
  So it is necessary to provide a default value for "unknown native"
  tune targets (i.e. -mtune=native while PRID does not correspond to
- any known "-mtune" type).  Currently all numbers are default.  */
+ any known "-mtune" type).  */
 array_tune<loongarch_rtx_cost_data> loongarch_cpu_rtx_cost_data =
-  array_tune<loongarch_rtx_cost_data> ();
+  array_tune<loongarch_rtx_cost_data> ()
+    .set (CPU_LA664,
+	  loongarch_rtx_cost_data ()
+	    .movcf2gr_ (COSTS_N_INSNS (1))
+	    .movgr2cf_ (COSTS_N_INSNS (1)));
 
 /* RTX costs to use when optimizing for size.
    We use a value slightly larger than COSTS_N_INSNS (1) for all of them
@@ -125,7 +131,8 @@ const loongarch_rtx_cost_data loongarch_rtx_cost_optimize_size =
     .int_mult_si_ (COST_COMPLEX_INSN)
     .int_mult_di_ (COST_COMPLEX_INSN)
     .int_div_si_ (COST_COMPLEX_INSN)
-    .int_div_di_ (COST_COMPLEX_INSN);
+    .int_div_di_ (COST_COMPLEX_INSN)
+    .movcf2gr_ (COST_COMPLEX_INSN);
 
 array_tune<int> loongarch_cpu_issue_rate = array_tune<int> ()
   .set (CPU_NATIVE, 4)
diff --git a/gcc/config/loongarch/loongarch-tune.h b/gcc/config/loongarch/loongarch-tune.h
index 4aa01c54c08..7a75c8dd9d9 100644
--- a/gcc/config/loongarch/loongarch-tune.h
+++ b/gcc/config/loongarch/loongarch-tune.h
@@ -35,6 +35,8 @@ struct loongarch_rtx_cost_data
   unsigned short int_mult_di;
   unsigned short int_div_si;
   unsigned short int_div_di;
+  unsigned short movcf2gr;
+  unsigned short movgr2cf;
   unsigned short branch_cost;
   unsigned short memory_latency;
 
@@ -95,6 +97,18 @@ struct loongarch_rtx_cost_data
     return *this;
   }
 
+  loongarch_rtx_cost_data movcf2gr_ (unsigned short _movcf2gr)
+  {
+    movcf2gr = _movcf2gr;
+    return *this;
+  }
+
+  loongarch_rtx_cost_data movgr2cf_ (unsigned short _movgr2cf)
+  {
+    movgr2cf = _movgr2cf;
+    return *this;
+  }
+
   loongarch_rtx_cost_data branch_cost_ (unsigned short _branch_cost)
   {
     branch_cost = _branch_cost;
@@ -106,7 +120,6 @@ struct loongarch_rtx_cost_data
     memory_latency = _memory_latency;
     return *this;
   }
-
 };
 
 /* Costs to use when optimizing for size.  */
diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index 390e3206a17..d7fd203c1ab 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -5123,29 +5123,6 @@ loongarch_zero_if_equal (rtx cmp0, rtx cmp1)
 		       OPTAB_DIRECT);
 }
 
-/* Allocate a floating-point condition-code register of mode MODE.  */
-
-static rtx
-loongarch_allocate_fcc (machine_mode mode)
-{
-  unsigned int regno, count;
-
-  gcc_assert (TARGET_HARD_FLOAT);
-
-  if (mode == FCCmode)
-    count = 1;
-  else
-    gcc_unreachable ();
-
-  cfun->machine->next_fcc += -cfun->machine->next_fcc & (count - 1);
-  if (cfun->machine->next_fcc > FCC_REG_LAST - FCC_REG_FIRST)
-    cfun->machine->next_fcc = 0;
-
-  regno = FCC_REG_FIRST + cfun->machine->next_fcc;
-  cfun->machine->next_fcc += count;
-  return gen_rtx_REG (mode, regno);
-}
-
 /* Sign- or zero-extend OP0 and OP1 for integer comparisons.  */
 
 static void
@@ -5260,7 +5237,7 @@ loongarch_emit_float_compare (enum rtx_code *code, rtx *op0, rtx *op1)
      operands for FCMP.cond.fmt, instead a reversed condition code is
      required and a test for false.  */
   *code = NE;
-  *op0 = loongarch_allocate_fcc (FCCmode);
+  *op0 = gen_reg_rtx (FCCmode);
 
   *op1 = const0_rtx;
   loongarch_emit_binary (cmp_code, *op0, cmp_op0, cmp_op1);
@@ -6630,7 +6607,7 @@ loongarch_hard_regno_mode_ok_uncached (unsigned int regno, machine_mode mode)
   enum mode_class mclass;
 
   if (mode == FCCmode)
-    return FCC_REG_P (regno);
+    return FCC_REG_P (regno) || GP_REG_P (regno) || FP_REG_P (regno);
 
   size = GET_MODE_SIZE (mode);
   mclass = GET_MODE_CLASS (mode);
@@ -6845,6 +6822,9 @@ loongarch_move_to_gpr_cost (reg_class_t from)
       /* MOVFR2GR, etc.  */
       return 4;
 
+    case FCC_REGS:
+      return loongarch_cost->movcf2gr;
+
     default:
       return 0;
     }
@@ -6867,6 +6847,9 @@ loongarch_move_from_gpr_cost (reg_class_t to)
       /* MOVGR2FR, etc.  */
       return 4;
 
+    case FCC_REGS:
+      return loongarch_cost->movgr2cf;
+
     default:
       return 0;
     }
@@ -6901,6 +6884,10 @@ loongarch_register_move_cost (machine_mode mode, reg_class_t from,
   if (to == dregs)
     return loongarch_move_to_gpr_cost (from);
 
+  /* fcc -> fcc, fcc -> fpr, or fpr -> fcc. */
+  if (from == FCC_REGS || to == FCC_REGS)
+    return COSTS_N_INSNS (from == to ? 2 : 1);
+
   /* Handles cases that require a GPR temporary.  */
   cost1 = loongarch_move_to_gpr_cost (from);
   if (cost1 != 0)
@@ -6937,6 +6924,39 @@ loongarch_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x,
 
   regno = true_regnum (x);
 
+  if (mode == FCCmode)
+    {
+      if (reg_class_subset_p (rclass, FCC_REGS) && !FP_REG_P (regno))
+	{
+	  if (FCC_REG_P (regno))
+	    return FP_REGS;
+
+	  auto fn = in_p ? loongarch_move_from_gpr_cost
+			 : loongarch_move_to_gpr_cost;
+
+	  if (fn (FCC_REGS) > fn (FP_REGS) + COSTS_N_INSNS (1))
+	    return FP_REGS;
+
+	  return GP_REG_P (regno) ? NO_REGS : GR_REGS;
+	}
+
+      if (reg_class_subset_p (rclass, GR_REGS) && FCC_REG_P (regno))
+	{
+	  auto fn = in_p ? loongarch_move_to_gpr_cost
+			 : loongarch_move_from_gpr_cost;
+
+	  if (fn (FCC_REGS) > fn (FP_REGS) + COSTS_N_INSNS (1))
+	    return FP_REGS;
+
+	  return NO_REGS;
+	}
+
+      if (reg_class_subset_p (rclass, FP_REGS) && MEM_P (x))
+	return GR_REGS;
+
+      return NO_REGS;
+    }
+
   if (reg_class_subset_p (rclass, FP_REGS))
     {
       if (regno < 0
diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
index 404a663c1a6..c7058282a21 100644
--- a/gcc/config/loongarch/loongarch.md
+++ b/gcc/config/loongarch/loongarch.md
@@ -2283,11 +2283,72 @@ (define_expand "move_doubleword_fpr<mode>"
 
 ;; Clear one FCC register
 
-(define_insn "movfcc"
-  [(set (match_operand:FCC 0 "register_operand" "=z")
-	(const_int 0))]
+(define_expand "movfcc"
+  [(set (match_operand:FCC 0 "")
+	(match_operand:FCC 1 ""))]
+  "TARGET_HARD_FLOAT"
+{
+  if (memory_operand (operands[0], FCCmode)
+      && memory_operand (operands[1], FCCmode))
+    operands[1] = force_reg (FCCmode, operands[1]);
+})
+
+(define_insn "movfcc_internal"
+  [(set (match_operand:FCC 0 "nonimmediate_operand"
+			     "=z,z,*f,*f,*r,*r,*m,*f,*r,z,*r")
+	(match_operand:FCC 1 "reg_or_0_operand"
+			     "J,*f,z,*f,J*r,*m,J*r,J*r,*f,*r,z"))]
+  "TARGET_HARD_FLOAT"
+  "@
+   fcmp.caf.s\t%0,$f0,$f0
+   movfr2cf\t%0,%1
+   movcf2fr\t%0,%1
+   fmov.s\t%0,%1
+   or\t%0,%z1,$r0
+   ld.b\t%0,%1
+   st.b\t%z1,%0
+   movgr2fr.w\t%0,%1
+   movfr2gr.s\t%0,%1
+   movgr2cf\t%0,%1
+   movcf2gr\t%0,%1"
+  [(set_attr "type" "move")
+   (set_attr "mode" "FCC")])
+
+(define_insn "fcc_to_<X:mode>"
+  [(set (match_operand:X 0 "register_operand" "=r")
+	(if_then_else:X (ne (match_operand:FCC 1 "register_operand" "0")
+			    (const_int 0))
+			(const_int 1)
+			(const_int 0)))]
+  "TARGET_HARD_FLOAT"
   ""
-  "fcmp.caf.s\t%0,$f0,$f0")
+  [(set_attr "length" "0")
+   (set_attr "type" "ghost")])
+
+(define_expand "cstore<ANYF:mode>4"
+  [(set (match_operand:SI 0 "register_operand")
+	(match_operator:SI 1 "loongarch_fcmp_operator"
+	  [(match_operand:ANYF 2 "register_operand")
+	   (match_operand:ANYF 3 "register_operand")]))]
+  ""
+  {
+    rtx fcc = gen_reg_rtx (FCCmode);
+    rtx cmp = gen_rtx_fmt_ee (GET_CODE (operands[1]), FCCmode,
+			      operands[2], operands[3]);
+
+    emit_insn (gen_rtx_SET (fcc, cmp));
+    if (TARGET_64BIT)
+      {
+	rtx gpr = gen_reg_rtx (DImode);
+	emit_insn (gen_fcc_to_di (gpr, fcc));
+	emit_insn (gen_rtx_SET (operands[0],
+				lowpart_subreg (SImode, gpr, DImode)));
+      }
+    else
+      emit_insn (gen_fcc_to_si (operands[0], fcc));
+
+    DONE;
+  })
 
 ;; Conditional move instructions.
 
diff --git a/gcc/config/loongarch/predicates.md b/gcc/config/loongarch/predicates.md
index 9e9ce58cb53..83fea08315c 100644
--- a/gcc/config/loongarch/predicates.md
+++ b/gcc/config/loongarch/predicates.md
@@ -590,6 +590,10 @@ (define_predicate "order_operator"
 (define_predicate "loongarch_cstore_operator"
   (match_code "ne,eq,gt,gtu,ge,geu,lt,ltu,le,leu"))
 
+(define_predicate "loongarch_fcmp_operator"
+  (match_code
+    "unordered,uneq,unlt,unle,eq,lt,le,ordered,ltgt,ne,ge,gt,unge,ungt"))
+
 (define_predicate "small_data_pattern"
   (and (match_code "set,parallel,unspec,unspec_volatile,prefetch")
        (match_test "loongarch_small_data_pattern_p (op)")))
diff --git a/gcc/testsuite/gcc.target/loongarch/movcf2gr-via-fr.c b/gcc/testsuite/gcc.target/loongarch/movcf2gr-via-fr.c
new file mode 100644
index 00000000000..23334a3a31f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/movcf2gr-via-fr.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=loongarch64 -mtune=la464 -mabi=lp64d" } */
+/* { dg-final { scan-assembler "movcf2fr\t\\\$f\[0-9\]+,\\\$fcc" } } */
+/* { dg-final { scan-assembler "movfr2gr\\.s\t\\\$r4" } } */
+
+int
+t (float a, float b)
+{
+  return a > b;
+}
diff --git a/gcc/testsuite/gcc.target/loongarch/movcf2gr.c b/gcc/testsuite/gcc.target/loongarch/movcf2gr.c
new file mode 100644
index 00000000000..d27c393b5ed
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/movcf2gr.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=loongarch64 -mtune=la664 -mabi=lp64d" } */
+/* { dg-final { scan-assembler "movcf2gr\t\\\$r4,\\\$fcc" } } */
+
+int
+t (float a, float b)
+{
+  return a > b;
+}
-- 
2.43.0


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