i386: Rounding functions TLC

Use copy_to_reg where appropriate, use int_mode_for_mode
and fix comment indentation.

2020-12-29  Uroš Bizjak  <ubizjak@gmail.com>

gcc/
	* config/i386/i386-expand.c (ix86_gen_TWO52): Use REAL_MODE_FORMAT
	to determine number of mantissa bits.  Use real_2expN instead
	of real_ldexp.
	(ix86_expand_rint): Use copy_to_reg.
	(ix86_expand_floorceildf_32): Ditto.
	(ix86_expand_truncdf_32): Ditto.
	(ix86_expand_rounddf_32): Ditto.
	(ix86_expand_floorceil): Use copy_to_reg and int_mode_for_mode.
	(ix86_expand_trunc): Ditto.
	(ix86_expand_round): Ditto.

diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c
index 5c48cded9543cf47a2b81df8547c4563393a54c0..6e08fd327265047f78912c609a009d565432057c 100644 (file)
--- a/gcc/config/i386/i386-expand.c
+++ b/gcc/config/i386/i386-expand.c
@@ -16214,8 +16214,8 @@ void
 ix86_expand_lround (rtx op0, rtx op1)
 {
   /* C code for the stuff we're doing below:
-       tmp = op1 + copysign (nextafter (0.5, 0.0), op1)
-       return (long)tmp;
+       tmp = op1 + copysign (nextafter (0.5, 0.0), op1)
+       return (long)tmp;
    */
   machine_mode mode = GET_MODE (op1);
   const struct real_format *fmt;
@@ -16246,8 +16246,8 @@ ix86_expand_lfloorceil (rtx op0, rtx op1, bool do_floor)
 {
   /* C code for the stuff we're doing below (for do_floor):
        xi = (long)op1;
-        xi -= (double)xi > op1 ? 1 : 0;
-        return xi;
+       xi -= (double)xi > op1 ? 1 : 0;
+       return xi;
    */
   machine_mode fmode = GET_MODE (op1);
   machine_mode imode = GET_MODE (op0);
@@ -16281,10 +16281,12 @@ ix86_expand_lfloorceil (rtx op0, rtx op1, bool do_floor)
 static rtx
 ix86_gen_TWO52 (machine_mode mode)
 {
+  const struct real_format *fmt;
   REAL_VALUE_TYPE TWO52r;
   rtx TWO52;
 
-  real_ldexp (&TWO52r, &dconst1, mode == DFmode ? 52 : 23);
+  fmt = REAL_MODE_FORMAT (mode);
+  real_2expN (&TWO52r, fmt->p - 1, mode);
   TWO52 = const_double_from_real_value (TWO52r, mode);
   TWO52 = force_reg (mode, TWO52);
 
@@ -16298,29 +16300,31 @@ ix86_expand_rint (rtx operand0, rtx operand1)
 {
   /* C code for the stuff we're doing below:
        xa = fabs (operand1);
-        if (!isless (xa, 2**52))
+       if (!isless (xa, 2**52))
          return operand1;
-        two52 = 2**52;
-        if (flag_rounding_math)
+       two52 = 2**52;
+       if (flag_rounding_math)
          {
            two52 = copysign (two52, operand1);
            xa = operand1;
          }
-        xa = xa + two52 - two52;
-        return copysign (xa, operand1);
+       xa = xa + two52 - two52;
+       return copysign (xa, operand1);
    */
   machine_mode mode = GET_MODE (operand0);
   rtx res, xa, TWO52, mask;
   rtx_code_label *label;
 
-  res = gen_reg_rtx (mode);
-  emit_move_insn (res, operand1);
+  TWO52 = ix86_gen_TWO52 (mode);
+
+  /* Temporary for holding the result, initialized to the input
+     operand to ease control flow.  */
+  res = copy_to_reg (operand1);
 
   /* xa = abs (operand1) */
   xa = ix86_expand_sse_fabs (res, &mask);
 
   /* if (!isless (xa, TWO52)) goto label; */
-  TWO52 = ix86_gen_TWO52 (mode);
   label = ix86_expand_sse_compare_and_jump (UNLE, TWO52, xa, false);
 
   if (flag_rounding_math)
@@ -16351,8 +16355,8 @@ ix86_expand_floorceil (rtx operand0, rtx operand1, bool do_floor)
 {
   /* C code for the stuff we expand below.
        double xa = fabs (x), x2;
-        if (!isless (xa, TWO52))
-          return x;
+       if (!isless (xa, TWO52))
+         return x;
        x2 = (double)(long)x;
 
      Compensate.  Floor:
@@ -16374,8 +16378,7 @@ ix86_expand_floorceil (rtx operand0, rtx operand1, bool do_floor)
 
   /* Temporary for holding the result, initialized to the input
      operand to ease control flow.  */
-  res = gen_reg_rtx (mode);
-  emit_move_insn (res, operand1);
+  res = copy_to_reg (operand1);
 
   /* xa = abs (operand1) */
   xa = ix86_expand_sse_fabs (res, &mask);
@@ -16384,7 +16387,7 @@ ix86_expand_floorceil (rtx operand0, rtx operand1, bool do_floor)
   label = ix86_expand_sse_compare_and_jump (UNLE, TWO52, xa, false);
 
   /* xa = (double)(long)x */
-  xi = gen_reg_rtx (mode == DFmode ? DImode : SImode);
+  xi = gen_reg_rtx (int_mode_for_mode (mode).require ());
   expand_fix (xi, res, 0);
   expand_float (xa, xi, 0);
 
@@ -16419,18 +16422,18 @@ void
 ix86_expand_floorceildf_32 (rtx operand0, rtx operand1, bool do_floor)
 {
   /* C code for the stuff we expand below.
-        double xa = fabs (x), x2;
-        if (!isless (xa, TWO52))
-          return x;
-        xa = xa + TWO52 - TWO52;
-        x2 = copysign (xa, x);
+       double xa = fabs (x), x2;
+       if (!isless (xa, TWO52))
+         return x;
+       xa = xa + TWO52 - TWO52;
+       x2 = copysign (xa, x);
 
      Compensate.  Floor:
-        if (x2 > x)
-          x2 -= 1;
+       if (x2 > x)
+         x2 -= 1;
      Compensate.  Ceil:
-        if (x2 < x)
-          x2 += 1;
+       if (x2 < x)
+         x2 += 1;
 
        if (HONOR_SIGNED_ZEROS (mode))
          x2 = copysign (x2, x);
@@ -16444,8 +16447,7 @@ ix86_expand_floorceildf_32 (rtx operand0, rtx operand1, bool do_floor)
 
   /* Temporary for holding the result, initialized to the input
      operand to ease control flow.  */
-  res = gen_reg_rtx (mode);
-  emit_move_insn (res, operand1);
+  res = copy_to_reg (operand1);
 
   /* xa = abs (operand1) */
   xa = ix86_expand_sse_fabs (res, &mask);
@@ -16490,10 +16492,10 @@ void
 ix86_expand_trunc (rtx operand0, rtx operand1)
 {
   /* C code for SSE variant we expand below.
-        double xa = fabs (x), x2;
-        if (!isless (xa, TWO52))
-          return x;
-        x2 = (double)(long)x;
+       double xa = fabs (x), x2;
+       if (!isless (xa, TWO52))
+         return x;
+       x2 = (double)(long)x;
        if (HONOR_SIGNED_ZEROS (mode))
          return copysign (x2, x);
        return x2;
@@ -16506,8 +16508,7 @@ ix86_expand_trunc (rtx operand0, rtx operand1)
 
   /* Temporary for holding the result, initialized to the input
      operand to ease control flow.  */
-  res = gen_reg_rtx (mode);
-  emit_move_insn (res, operand1);
+  res = copy_to_reg (operand1);
 
   /* xa = abs (operand1) */
   xa = ix86_expand_sse_fabs (res, &mask);
@@ -16516,7 +16517,7 @@ ix86_expand_trunc (rtx operand0, rtx operand1)
   label = ix86_expand_sse_compare_and_jump (UNLE, TWO52, xa, false);
 
   /* xa = (double)(long)x */
-  xi = gen_reg_rtx (mode == DFmode ? DImode : SImode);
+  xi = gen_reg_rtx (int_mode_for_mode (mode).require ());
   expand_fix (xi, res, 0);
   expand_float (xa, xi, 0);
 
@@ -16542,23 +16543,22 @@ ix86_expand_truncdf_32 (rtx operand0, rtx operand1)
   rtx_code_label *label;
 
   /* C code for SSE variant we expand below.
-        double xa = fabs (x), x2;
-        if (!isless (xa, TWO52))
-          return x;
-        xa2 = xa + TWO52 - TWO52;
+       double xa = fabs (x), x2;
+       if (!isless (xa, TWO52))
+         return x;
+       xa2 = xa + TWO52 - TWO52;
      Compensate:
-        if (xa2 > xa)
-          xa2 -= 1.0;
-        x2 = copysign (xa2, x);
-        return x2;
+       if (xa2 > xa)
+         xa2 -= 1.0;
+       x2 = copysign (xa2, x);
+       return x2;
    */
 
   TWO52 = ix86_gen_TWO52 (mode);
 
   /* Temporary for holding the result, initialized to the input
      operand to ease control flow.  */
-  res = gen_reg_rtx (mode);
-  emit_move_insn (res, operand1);
+  res =copy_to_reg (operand1);
 
   /* xa = abs (operand1) */
   xa = ix86_expand_sse_fabs (res, &mask);
@@ -16597,11 +16597,11 @@ void
 ix86_expand_round (rtx operand0, rtx operand1)
 {
   /* C code for the stuff we're doing below:
-        double xa = fabs (x);
-        if (!isless (xa, TWO52))
-          return x;
-        xa = (double)(long)(xa + nextafter (0.5, 0.0));
-        return copysign (xa, x);
+       double xa = fabs (x);
+       if (!isless (xa, TWO52))
+         return x;
+       xa = (double)(long)(xa + nextafter (0.5, 0.0));
+       return copysign (xa, x);
    */
   machine_mode mode = GET_MODE (operand0);
   rtx res, TWO52, xa, xi, half, mask;
@@ -16611,8 +16611,7 @@ ix86_expand_round (rtx operand0, rtx operand1)
 
   /* Temporary for holding the result, initialized to the input
      operand to ease control flow.  */
-  res = gen_reg_rtx (mode);
-  emit_move_insn (res, operand1);
+  res = copy_to_reg (operand1);
 
   TWO52 = ix86_gen_TWO52 (mode);
   xa = ix86_expand_sse_fabs (res, &mask);
@@ -16628,7 +16627,7 @@ ix86_expand_round (rtx operand0, rtx operand1)
   xa = expand_simple_binop (mode, PLUS, xa, half, NULL_RTX, 0, OPTAB_DIRECT);
 
   /* xa = (double)(int64_t)xa */
-  xi = gen_reg_rtx (mode == DFmode ? DImode : SImode);
+  xi = gen_reg_rtx (int_mode_for_mode (mode).require ());
   expand_fix (xi, xa, 0);
   expand_float (xa, xi, 0);
 
@@ -16648,20 +16647,20 @@ void
 ix86_expand_rounddf_32 (rtx operand0, rtx operand1)
 {
   /* C code for the stuff we expand below.
-        double xa = fabs (x), xa2, x2;
-        if (!isless (xa, TWO52))
-          return x;
+       double xa = fabs (x), xa2, x2;
+       if (!isless (xa, TWO52))
+         return x;
      Using the absolute value and copying back sign makes
      -0.0 -> -0.0 correct.
-        xa2 = xa + TWO52 - TWO52;
+       xa2 = xa + TWO52 - TWO52;
      Compensate.
        dxa = xa2 - xa;
-        if (dxa <= -0.5)
-          xa2 += 1;
-        else if (dxa > 0.5)
-          xa2 -= 1;
-        x2 = copysign (xa2, x);
-        return x2;
+       if (dxa <= -0.5)
+         xa2 += 1;
+       else if (dxa > 0.5)
+         xa2 -= 1;
+       x2 = copysign (xa2, x);
+       return x2;
    */
   machine_mode mode = GET_MODE (operand0);
   rtx xa, xa2, dxa, TWO52, tmp, half, mhalf, one, res, mask;
@@ -16671,8 +16670,7 @@ ix86_expand_rounddf_32 (rtx operand0, rtx operand1)
 
   /* Temporary for holding the result, initialized to the input
      operand to ease control flow.  */
-  res = gen_reg_rtx (mode);
-  emit_move_insn (res, operand1);
+  res = copy_to_reg (operand1);
 
   /* xa = abs (operand1) */
   xa = ix86_expand_sse_fabs (res, &mask);