remove nested function hack_digit
diff mbox

Message ID CAGQ9bdwzvk+h=39NuJG+7TvpKu+m6j8=nGZrhidAWxiNeTuJBQ@mail.gmail.com
State New
Headers show

Commit Message

Konstantin Serebryany Sept. 22, 2014, 11:42 p.m. UTC
Here is a better formatted and tested patch that uses a single parameter.
The generated code is nearly identical (same instructions, differences
only in constant offsets).


On Mon, Sep 22, 2014 at 3:52 PM, Konstantin Serebryany
<konstantin.s.serebryany@gmail.com> wrote:
> On Mon, Sep 22, 2014 at 3:45 PM, Roland McGrath <roland@hack.frob.com> wrote:
>>> hack_digit becomes longer too due to longer function prologue epilogue:
>>
>> Clearly that cannot be the only difference.  Was the function's code itself
>> actually all nearly identical, modulo trivial differences like different
>> register allocation choices?  Each access to one of the parent's locals
>> surely looks different, and how different that code looks is probably where
>> the most important differences are.
>
> Another difference is that the compile decided to rearrange the order
> of basic blocks, so the calls go in different orders.
> I've attached the disassembly for both variants.
>
>>
>>> I considered doing such a patch but it turned out a huge textual
>>> change that will make the code much less readable.
>>> Still, let me do it and send it here anyway, unless you tell me no to.
>>
>> Of course readability is very subjective, so there really is no substitute
>> for each interested person just seeing how things look and giving their
>> opinion.  The most trivial mechanical change might harm readability in ways
>> that can be improved with a little thought.
>
> Attached is a patch with "trivial mechanical change" (not properly
> formatted yet).
> To me it looks horrible. Does it make sense to invest more time in it?

Comments

Roland McGrath Sept. 26, 2014, 7:38 p.m. UTC | #1
> Here is a better formatted and tested patch that uses a single parameter.
> The generated code is nearly identical (same instructions, differences
> only in constant offsets).

This change looks mostly OK to me.  It's not clear to me what you're saying
this version's generated code is identical to.  If you're just saying it's
identical to the version of the patch that differs only cosmetically, then
that's not interesting.  The clear comparison of the trunk code to the
patched code is what we need.  It's not especially helpful to attach the
whole disassembly (we can all compile it for ourselves).  What's important
is to do the careful analysis of the code differences and explain their
expected performance impact.

> +2014-09-15  Kostya Serebryany  <konstantin.s.serebryany@gmail.com>

In patch submissions, the log entry should not be part of the patch.

> +	* stdio-common/printf_fp.c (hack_digit): New function.
> +	(___printf_fp): Remove nested function hack_digit. Call non-nested
> +	function hack_digit.

Two spaces between sentences.  I would have written this:

	* stdio-common/printf_fp.c
	(hack_digit): New function, broken out of ...
	(__printf_fp): ... local function here.  Update call sites.
	hack_digit now takes an additional parameter that is a pointer
	to a struct of the referenced locals.  Those locals moved inside
	the struct and references updated.

> +static wchar_t hack_digit (struct hack_digit_param *p)
> +{

The parts of the declaration before the function name get their own line,
with the function name starting the next line.

You didn't report what testing you did on this patch.


Thanks,
Roland

Patch
diff mbox

diff --git a/ChangeLog b/ChangeLog
index a40fb46..ab82739 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@ 
+2014-09-15  Kostya Serebryany  <konstantin.s.serebryany@gmail.com>
+
+	* stdio-common/printf_fp.c (hack_digit): New function.
+	(___printf_fp): Remove nested function hack_digit. Call non-nested
+	function hack_digit.
+
 2014-09-15  Andreas Schwab  <schwab@linux-m68k.org>
 
 	[BZ #17371]
diff --git a/stdio-common/printf_fp.c b/stdio-common/printf_fp.c
index 9cd4b4b..8e68537 100644
--- a/stdio-common/printf_fp.c
+++ b/stdio-common/printf_fp.c
@@ -148,6 +148,64 @@  static wchar_t *group_number (wchar_t *buf, wchar_t *bufend,
 			      wchar_t thousands_sep, int ngroups)
      internal_function;
 
+struct hack_digit_param
+{
+  /* Sign of the exponent.  */
+  int expsign;
+  /* The type of output format that will be used: 'e'/'E' or 'f'.  */
+  int type;
+  /* and the exponent.	*/
+  int exponent;
+  /* The fraction of the floting-point value in question  */
+  MPN_VAR(frac);
+  /* Scaling factor.  */
+  MPN_VAR(scale);
+  /* Temporary bignum value.  */
+  MPN_VAR(tmp);
+};
+
+static wchar_t hack_digit (struct hack_digit_param *p)
+{
+  mp_limb_t hi;
+
+  if (p->expsign != 0 && p->type == 'f' && p->exponent-- > 0)
+    hi = 0;
+  else if (p->scalesize == 0)
+    {
+      hi = p->frac[p->fracsize - 1];
+      p->frac[p->fracsize - 1] = __mpn_mul_1 (p->frac, p->frac,
+	p->fracsize - 1, 10);
+    }
+  else
+    {
+      if (p->fracsize < p->scalesize)
+	hi = 0;
+      else
+	{
+	  hi = mpn_divmod (p->tmp, p->frac, p->fracsize,
+	    p->scale, p->scalesize);
+	  p->tmp[p->fracsize - p->scalesize] = hi;
+	  hi = p->tmp[0];
+
+	  p->fracsize = p->scalesize;
+	  while (p->fracsize != 0 && p->frac[p->fracsize - 1] == 0)
+	    --p->fracsize;
+	  if (p->fracsize == 0)
+	    {
+	      /* We're not prepared for an mpn variable with zero
+		 limbs.  */
+	      p->fracsize = 1;
+	      return L'0' + hi;
+	    }
+	}
+
+      mp_limb_t _cy = __mpn_mul_1 (p->frac, p->frac, p->fracsize, 10);
+      if (_cy != 0)
+	p->frac[p->fracsize++] = _cy;
+    }
+
+  return L'0' + hi;
+}
 
 int
 ___printf_fp (FILE *fp,
@@ -181,24 +239,10 @@  ___printf_fp (FILE *fp,
   /* We need to shift the contents of fp_input by this amount of bits.	*/
   int to_shift = 0;
 
-  /* The fraction of the floting-point value in question  */
-  MPN_VAR(frac);
-  /* and the exponent.	*/
-  int exponent;
-  /* Sign of the exponent.  */
-  int expsign = 0;
+  struct hack_digit_param p;
   /* Sign of float number.  */
   int is_neg = 0;
 
-  /* Scaling factor.  */
-  MPN_VAR(scale);
-
-  /* Temporary bignum value.  */
-  MPN_VAR(tmp);
-
-  /* The type of output format that will be used: 'e'/'E' or 'f'.  */
-  int type;
-
   /* Counter for number of written characters.	*/
   int done = 0;
 
@@ -213,49 +257,7 @@  ___printf_fp (FILE *fp,
   /* Flag whether wbuffer is malloc'ed or not.  */
   int buffer_malloced = 0;
 
-  auto wchar_t hack_digit (void);
-
-  wchar_t hack_digit (void)
-    {
-      mp_limb_t hi;
-
-      if (expsign != 0 && type == 'f' && exponent-- > 0)
-	hi = 0;
-      else if (scalesize == 0)
-	{
-	  hi = frac[fracsize - 1];
-	  frac[fracsize - 1] = __mpn_mul_1 (frac, frac, fracsize - 1, 10);
-	}
-      else
-	{
-	  if (fracsize < scalesize)
-	    hi = 0;
-	  else
-	    {
-	      hi = mpn_divmod (tmp, frac, fracsize, scale, scalesize);
-	      tmp[fracsize - scalesize] = hi;
-	      hi = tmp[0];
-
-	      fracsize = scalesize;
-	      while (fracsize != 0 && frac[fracsize - 1] == 0)
-		--fracsize;
-	      if (fracsize == 0)
-		{
-		  /* We're not prepared for an mpn variable with zero
-		     limbs.  */
-		  fracsize = 1;
-		  return L'0' + hi;
-		}
-	    }
-
-	  mp_limb_t _cy = __mpn_mul_1 (frac, frac, fracsize, 10);
-	  if (_cy != 0)
-	    frac[fracsize++] = _cy;
-	}
-
-      return L'0' + hi;
-    }
-
+  p.expsign = 0;
 
   /* Figure out the decimal point character.  */
   if (info->extra == 0)
@@ -360,12 +362,12 @@  ___printf_fp (FILE *fp,
 	}
       else
 	{
-	  fracsize = __mpn_extract_long_double (fp_input,
+	  p.fracsize = __mpn_extract_long_double (fp_input,
 						(sizeof (fp_input) /
 						 sizeof (fp_input[0])),
-						&exponent, &is_neg,
+						&p.exponent, &is_neg,
 						fpnum.ldbl);
-	  to_shift = 1 + fracsize * BITS_PER_MP_LIMB - LDBL_MANT_DIG;
+	  to_shift = 1 + p.fracsize * BITS_PER_MP_LIMB - LDBL_MANT_DIG;
 	}
     }
   else
@@ -406,11 +408,11 @@  ___printf_fp (FILE *fp,
 	}
       else
 	{
-	  fracsize = __mpn_extract_double (fp_input,
+	  p.fracsize = __mpn_extract_double (fp_input,
 					   (sizeof (fp_input)
 					    / sizeof (fp_input[0])),
-					   &exponent, &is_neg, fpnum.dbl);
-	  to_shift = 1 + fracsize * BITS_PER_MP_LIMB - DBL_MANT_DIG;
+					   &p.exponent, &is_neg, fpnum.dbl);
+	  to_shift = 1 + p.fracsize * BITS_PER_MP_LIMB - DBL_MANT_DIG;
 	}
     }
 
@@ -441,25 +443,25 @@  ___printf_fp (FILE *fp,
     }
 
 
-  /* We need three multiprecision variables.  Now that we have the exponent
+  /* We need three multiprecision variables.  Now that we have the p.exponent
      of the number we can allocate the needed memory.  It would be more
      efficient to use variables of the fixed maximum size but because this
      would be really big it could lead to memory problems.  */
   {
-    mp_size_t bignum_size = ((ABS (exponent) + BITS_PER_MP_LIMB - 1)
+    mp_size_t bignum_size = ((ABS (p.exponent) + BITS_PER_MP_LIMB - 1)
 			     / BITS_PER_MP_LIMB
 			     + (LDBL_MANT_DIG / BITS_PER_MP_LIMB > 2 ? 8 : 4))
 			    * sizeof (mp_limb_t);
-    frac = (mp_limb_t *) alloca (bignum_size);
-    tmp = (mp_limb_t *) alloca (bignum_size);
-    scale = (mp_limb_t *) alloca (bignum_size);
+    p.frac = (mp_limb_t *) alloca (bignum_size);
+    p.tmp = (mp_limb_t *) alloca (bignum_size);
+    p.scale = (mp_limb_t *) alloca (bignum_size);
   }
 
   /* We now have to distinguish between numbers with positive and negative
      exponents because the method used for the one is not applicable/efficient
      for the other.  */
-  scalesize = 0;
-  if (exponent > 2)
+  p.scalesize = 0;
+  if (p.exponent > 2)
     {
       /* |FP| >= 8.0.  */
       int scaleexpo = 0;
@@ -468,22 +470,23 @@  ___printf_fp (FILE *fp,
       const struct mp_power *powers = &_fpioconst_pow10[explog + 1];
       int cnt_h, cnt_l, i;
 
-      if ((exponent + to_shift) % BITS_PER_MP_LIMB == 0)
+      if ((p.exponent + to_shift) % BITS_PER_MP_LIMB == 0)
 	{
-	  MPN_COPY_DECR (frac + (exponent + to_shift) / BITS_PER_MP_LIMB,
-			 fp_input, fracsize);
-	  fracsize += (exponent + to_shift) / BITS_PER_MP_LIMB;
+	  MPN_COPY_DECR (p.frac + (p.exponent + to_shift) / BITS_PER_MP_LIMB,
+			 fp_input, p.fracsize);
+	  p.fracsize += (p.exponent + to_shift) / BITS_PER_MP_LIMB;
 	}
       else
 	{
-	  cy = __mpn_lshift (frac + (exponent + to_shift) / BITS_PER_MP_LIMB,
-			     fp_input, fracsize,
-			     (exponent + to_shift) % BITS_PER_MP_LIMB);
-	  fracsize += (exponent + to_shift) / BITS_PER_MP_LIMB;
+	  cy = __mpn_lshift (p.frac +
+			     (p.exponent + to_shift) / BITS_PER_MP_LIMB,
+			     fp_input, p.fracsize,
+			     (p.exponent + to_shift) % BITS_PER_MP_LIMB);
+	  p.fracsize += (p.exponent + to_shift) / BITS_PER_MP_LIMB;
 	  if (cy)
-	    frac[fracsize++] = cy;
+	    p.frac[p.fracsize++] = cy;
 	}
-      MPN_ZERO (frac, (exponent + to_shift) / BITS_PER_MP_LIMB);
+      MPN_ZERO (p.frac, (p.exponent + to_shift) / BITS_PER_MP_LIMB);
 
       assert (powers > &_fpioconst_pow10[0]);
       do
@@ -492,9 +495,9 @@  ___printf_fp (FILE *fp,
 
 	  /* The number of the product of two binary numbers with n and m
 	     bits respectively has m+n or m+n-1 bits.	*/
-	  if (exponent >= scaleexpo + powers->p_expo - 1)
+	  if (p.exponent >= scaleexpo + powers->p_expo - 1)
 	    {
-	      if (scalesize == 0)
+	      if (p.scalesize == 0)
 		{
 #ifndef __NO_LONG_DOUBLE_MATH
 		  if (LDBL_MANT_DIG > _FPIO_CONST_OFFSET * BITS_PER_MP_LIMB
@@ -505,61 +508,62 @@  ___printf_fp (FILE *fp,
    - _FPIO_CONST_OFFSET)
 		      /* 64bit const offset is not enough for
 			 IEEE quad long double.  */
-		      tmpsize = powers->arraysize + _FPIO_CONST_SHIFT;
-		      memcpy (tmp + _FPIO_CONST_SHIFT,
+		      p.tmpsize = powers->arraysize + _FPIO_CONST_SHIFT;
+		      memcpy (p.tmp + _FPIO_CONST_SHIFT,
 			      &__tens[powers->arrayoff],
-			      tmpsize * sizeof (mp_limb_t));
-		      MPN_ZERO (tmp, _FPIO_CONST_SHIFT);
-		      /* Adjust exponent, as scaleexpo will be this much
+			      p.tmpsize * sizeof (mp_limb_t));
+		      MPN_ZERO (p.tmp, _FPIO_CONST_SHIFT);
+		      /* Adjust p.exponent, as scaleexpo will be this much
 			 bigger too.  */
-		      exponent += _FPIO_CONST_SHIFT * BITS_PER_MP_LIMB;
+		      p.exponent += _FPIO_CONST_SHIFT * BITS_PER_MP_LIMB;
 		    }
 		  else
 #endif
 		    {
-		      tmpsize = powers->arraysize;
-		      memcpy (tmp, &__tens[powers->arrayoff],
-			      tmpsize * sizeof (mp_limb_t));
+		      p.tmpsize = powers->arraysize;
+		      memcpy (p.tmp, &__tens[powers->arrayoff],
+			      p.tmpsize * sizeof (mp_limb_t));
 		    }
 		}
 	      else
 		{
-		  cy = __mpn_mul (tmp, scale, scalesize,
+		  cy = __mpn_mul (p.tmp, p.scale, p.scalesize,
 				  &__tens[powers->arrayoff
 					 + _FPIO_CONST_OFFSET],
 				  powers->arraysize - _FPIO_CONST_OFFSET);
-		  tmpsize = scalesize + powers->arraysize - _FPIO_CONST_OFFSET;
+		  p.tmpsize = p.scalesize +
+		    powers->arraysize - _FPIO_CONST_OFFSET;
 		  if (cy == 0)
-		    --tmpsize;
+		    --p.tmpsize;
 		}
 
-	      if (MPN_GE (frac, tmp))
+	      if (MPN_GE (p.frac, p.tmp))
 		{
 		  int cnt;
-		  MPN_ASSIGN (scale, tmp);
-		  count_leading_zeros (cnt, scale[scalesize - 1]);
-		  scaleexpo = (scalesize - 2) * BITS_PER_MP_LIMB - cnt - 1;
+		  MPN_ASSIGN (p.scale, p.tmp);
+		  count_leading_zeros (cnt, p.scale[p.scalesize - 1]);
+		  scaleexpo = (p.scalesize - 2) * BITS_PER_MP_LIMB - cnt - 1;
 		  exp10 |= 1 << explog;
 		}
 	    }
 	  --explog;
 	}
       while (powers > &_fpioconst_pow10[0]);
-      exponent = exp10;
+      p.exponent = exp10;
 
       /* Optimize number representations.  We want to represent the numbers
 	 with the lowest number of bytes possible without losing any
 	 bytes. Also the highest bit in the scaling factor has to be set
 	 (this is a requirement of the MPN division routines).  */
-      if (scalesize > 0)
+      if (p.scalesize > 0)
 	{
 	  /* Determine minimum number of zero bits at the end of
 	     both numbers.  */
-	  for (i = 0; scale[i] == 0 && frac[i] == 0; i++)
+	  for (i = 0; p.scale[i] == 0 && p.frac[i] == 0; i++)
 	    ;
 
 	  /* Determine number of bits the scaling factor is misplaced.	*/
-	  count_leading_zeros (cnt_h, scale[scalesize - 1]);
+	  count_leading_zeros (cnt_h, p.scale[p.scalesize - 1]);
 
 	  if (cnt_h == 0)
 	    {
@@ -567,27 +571,27 @@  ___printf_fp (FILE *fp,
 		 we only have to remove the trailing empty limbs.  */
 	      if (i > 0)
 		{
-		  MPN_COPY_INCR (scale, scale + i, scalesize - i);
-		  scalesize -= i;
-		  MPN_COPY_INCR (frac, frac + i, fracsize - i);
-		  fracsize -= i;
+		  MPN_COPY_INCR (p.scale, p.scale + i, p.scalesize - i);
+		  p.scalesize -= i;
+		  MPN_COPY_INCR (p.frac, p.frac + i, p.fracsize - i);
+		  p.fracsize -= i;
 		}
 	    }
 	  else
 	    {
-	      if (scale[i] != 0)
+	      if (p.scale[i] != 0)
 		{
-		  count_trailing_zeros (cnt_l, scale[i]);
-		  if (frac[i] != 0)
+		  count_trailing_zeros (cnt_l, p.scale[i]);
+		  if (p.frac[i] != 0)
 		    {
 		      int cnt_l2;
-		      count_trailing_zeros (cnt_l2, frac[i]);
+		      count_trailing_zeros (cnt_l2, p.frac[i]);
 		      if (cnt_l2 < cnt_l)
 			cnt_l = cnt_l2;
 		    }
 		}
 	      else
-		count_trailing_zeros (cnt_l, frac[i]);
+		count_trailing_zeros (cnt_l, p.frac[i]);
 
 	      /* Now shift the numbers to their optimal position.  */
 	      if (i == 0 && BITS_PER_MP_LIMB - cnt_h > cnt_l)
@@ -595,10 +599,10 @@  ___printf_fp (FILE *fp,
 		  /* We cannot save any memory.	 So just roll both numbers
 		     so that the scaling factor has its highest bit set.  */
 
-		  (void) __mpn_lshift (scale, scale, scalesize, cnt_h);
-		  cy = __mpn_lshift (frac, frac, fracsize, cnt_h);
+		  (void) __mpn_lshift (p.scale, p.scale, p.scalesize, cnt_h);
+		  cy = __mpn_lshift (p.frac, p.frac, p.fracsize, cnt_h);
 		  if (cy != 0)
-		    frac[fracsize++] = cy;
+		    p.frac[p.fracsize++] = cy;
 		}
 	      else if (BITS_PER_MP_LIMB - cnt_h <= cnt_l)
 		{
@@ -606,31 +610,32 @@  ___printf_fp (FILE *fp,
 		     and by packing the non-zero limbs which gain another
 		     free one. */
 
-		  (void) __mpn_rshift (scale, scale + i, scalesize - i,
+		  (void) __mpn_rshift (p.scale, p.scale + i, p.scalesize - i,
 				       BITS_PER_MP_LIMB - cnt_h);
-		  scalesize -= i + 1;
-		  (void) __mpn_rshift (frac, frac + i, fracsize - i,
+		  p.scalesize -= i + 1;
+		  (void) __mpn_rshift (p.frac, p.frac + i, p.fracsize - i,
 				       BITS_PER_MP_LIMB - cnt_h);
-		  fracsize -= frac[fracsize - i - 1] == 0 ? i + 1 : i;
+		  p.fracsize -= p.frac[p.fracsize - i - 1] == 0 ? i + 1 : i;
 		}
 	      else
 		{
 		  /* We can only save the memory of the limbs which are zero.
 		     The non-zero parts occupy the same number of limbs.  */
 
-		  (void) __mpn_rshift (scale, scale + (i - 1),
-				       scalesize - (i - 1),
+		  (void) __mpn_rshift (p.scale, p.scale + (i - 1),
+				       p.scalesize - (i - 1),
 				       BITS_PER_MP_LIMB - cnt_h);
-		  scalesize -= i;
-		  (void) __mpn_rshift (frac, frac + (i - 1),
-				       fracsize - (i - 1),
+		  p.scalesize -= i;
+		  (void) __mpn_rshift (p.frac, p.frac + (i - 1),
+				       p.fracsize - (i - 1),
 				       BITS_PER_MP_LIMB - cnt_h);
-		  fracsize -= frac[fracsize - (i - 1) - 1] == 0 ? i : i - 1;
+		  p.fracsize -=
+		    p.frac[p.fracsize - (i - 1) - 1] == 0 ? i : i - 1;
 		}
 	    }
 	}
     }
-  else if (exponent < 0)
+  else if (p.exponent < 0)
     {
       /* |FP| < 1.0.  */
       int exp10 = 0;
@@ -638,48 +643,48 @@  ___printf_fp (FILE *fp,
       const struct mp_power *powers = &_fpioconst_pow10[explog + 1];
 
       /* Now shift the input value to its right place.	*/
-      cy = __mpn_lshift (frac, fp_input, fracsize, to_shift);
-      frac[fracsize++] = cy;
-      assert (cy == 1 || (frac[fracsize - 2] == 0 && frac[0] == 0));
+      cy = __mpn_lshift (p.frac, fp_input, p.fracsize, to_shift);
+      p.frac[p.fracsize++] = cy;
+      assert (cy == 1 || (p.frac[p.fracsize - 2] == 0 && p.frac[0] == 0));
 
-      expsign = 1;
-      exponent = -exponent;
+      p.expsign = 1;
+      p.exponent = -p.exponent;
 
       assert (powers != &_fpioconst_pow10[0]);
       do
 	{
 	  --powers;
 
-	  if (exponent >= powers->m_expo)
+	  if (p.exponent >= powers->m_expo)
 	    {
 	      int i, incr, cnt_h, cnt_l;
 	      mp_limb_t topval[2];
 
 	      /* The __mpn_mul function expects the first argument to be
 		 bigger than the second.  */
-	      if (fracsize < powers->arraysize - _FPIO_CONST_OFFSET)
-		cy = __mpn_mul (tmp, &__tens[powers->arrayoff
+	      if (p.fracsize < powers->arraysize - _FPIO_CONST_OFFSET)
+		cy = __mpn_mul (p.tmp, &__tens[powers->arrayoff
 					    + _FPIO_CONST_OFFSET],
 				powers->arraysize - _FPIO_CONST_OFFSET,
-				frac, fracsize);
+				p.frac, p.fracsize);
 	      else
-		cy = __mpn_mul (tmp, frac, fracsize,
+		cy = __mpn_mul (p.tmp, p.frac, p.fracsize,
 				&__tens[powers->arrayoff + _FPIO_CONST_OFFSET],
 				powers->arraysize - _FPIO_CONST_OFFSET);
-	      tmpsize = fracsize + powers->arraysize - _FPIO_CONST_OFFSET;
+	      p.tmpsize = p.fracsize + powers->arraysize - _FPIO_CONST_OFFSET;
 	      if (cy == 0)
-		--tmpsize;
+		--p.tmpsize;
 
-	      count_leading_zeros (cnt_h, tmp[tmpsize - 1]);
-	      incr = (tmpsize - fracsize) * BITS_PER_MP_LIMB
+	      count_leading_zeros (cnt_h, p.tmp[p.tmpsize - 1]);
+	      incr = (p.tmpsize - p.fracsize) * BITS_PER_MP_LIMB
 		     + BITS_PER_MP_LIMB - 1 - cnt_h;
 
 	      assert (incr <= powers->p_expo);
 
-	      /* If we increased the exponent by exactly 3 we have to test
+	      /* If we increased the p.exponent by exactly 3 we have to test
 		 for overflow.	This is done by comparing with 10 shifted
 		 to the right position.	 */
-	      if (incr == exponent + 3)
+	      if (incr == p.exponent + 3)
 		{
 		  if (cnt_h <= BITS_PER_MP_LIMB - 4)
 		    {
@@ -701,32 +706,32 @@  ___printf_fp (FILE *fp,
 		 against 10.0.  If it is greater or equal to 10.0 the
 		 multiplication was not valid.  This is because we cannot
 		 determine the number of bits in the result in advance.  */
-	      if (incr < exponent + 3
-		  || (incr == exponent + 3 &&
-		      (tmp[tmpsize - 1] < topval[1]
-		       || (tmp[tmpsize - 1] == topval[1]
-			   && tmp[tmpsize - 2] < topval[0]))))
+	      if (incr < p.exponent + 3
+		  || (incr == p.exponent + 3 &&
+		      (p.tmp[p.tmpsize - 1] < topval[1]
+		       || (p.tmp[p.tmpsize - 1] == topval[1]
+			   && p.tmp[p.tmpsize - 2] < topval[0]))))
 		{
 		  /* The factor is right.  Adapt binary and decimal
 		     exponents.	 */
-		  exponent -= incr;
+		  p.exponent -= incr;
 		  exp10 |= 1 << explog;
 
 		  /* If this factor yields a number greater or equal to
 		     1.0, we must not shift the non-fractional digits down. */
-		  if (exponent < 0)
-		    cnt_h += -exponent;
+		  if (p.exponent < 0)
+		    cnt_h += -p.exponent;
 
 		  /* Now we optimize the number representation.	 */
-		  for (i = 0; tmp[i] == 0; ++i);
+		  for (i = 0; p.tmp[i] == 0; ++i);
 		  if (cnt_h == BITS_PER_MP_LIMB - 1)
 		    {
-		      MPN_COPY (frac, tmp + i, tmpsize - i);
-		      fracsize = tmpsize - i;
+		      MPN_COPY (p.frac, p.tmp + i, p.tmpsize - i);
+		      p.fracsize = p.tmpsize - i;
 		    }
 		  else
 		    {
-		      count_trailing_zeros (cnt_l, tmp[i]);
+		      count_trailing_zeros (cnt_l, p.tmp[i]);
 
 		      /* Now shift the numbers to their optimal position.  */
 		      if (i == 0 && BITS_PER_MP_LIMB - 1 - cnt_h > cnt_l)
@@ -735,15 +740,16 @@  ___printf_fp (FILE *fp,
 			     number so that the leading digit is in a
 			     separate limb.  */
 
-			  cy = __mpn_lshift (frac, tmp, tmpsize, cnt_h + 1);
-			  fracsize = tmpsize + 1;
-			  frac[fracsize - 1] = cy;
+			  cy = __mpn_lshift (p.frac, p.tmp, p.tmpsize,
+			    cnt_h + 1);
+			  p.fracsize = p.tmpsize + 1;
+			  p.frac[p.fracsize - 1] = cy;
 			}
 		      else if (BITS_PER_MP_LIMB - 1 - cnt_h <= cnt_l)
 			{
-			  (void) __mpn_rshift (frac, tmp + i, tmpsize - i,
+			  (void) __mpn_rshift (p.frac, p.tmp + i, p.tmpsize - i,
 					       BITS_PER_MP_LIMB - 1 - cnt_h);
-			  fracsize = tmpsize - i;
+			  p.fracsize = p.tmpsize - i;
 			}
 		      else
 			{
@@ -751,41 +757,41 @@  ___printf_fp (FILE *fp,
 			     are zero.	The non-zero parts occupy the same
 			     number of limbs.  */
 
-			  (void) __mpn_rshift (frac, tmp + (i - 1),
-					       tmpsize - (i - 1),
+			  (void) __mpn_rshift (p.frac, p.tmp + (i - 1),
+					       p.tmpsize - (i - 1),
 					       BITS_PER_MP_LIMB - 1 - cnt_h);
-			  fracsize = tmpsize - (i - 1);
+			  p.fracsize = p.tmpsize - (i - 1);
 			}
 		    }
 		}
 	    }
 	  --explog;
 	}
-      while (powers != &_fpioconst_pow10[1] && exponent > 0);
+      while (powers != &_fpioconst_pow10[1] && p.exponent > 0);
       /* All factors but 10^-1 are tested now.	*/
-      if (exponent > 0)
+      if (p.exponent > 0)
 	{
 	  int cnt_l;
 
-	  cy = __mpn_mul_1 (tmp, frac, fracsize, 10);
-	  tmpsize = fracsize;
-	  assert (cy == 0 || tmp[tmpsize - 1] < 20);
+	  cy = __mpn_mul_1 (p.tmp, p.frac, p.fracsize, 10);
+	  p.tmpsize = p.fracsize;
+	  assert (cy == 0 || p.tmp[p.tmpsize - 1] < 20);
 
-	  count_trailing_zeros (cnt_l, tmp[0]);
-	  if (cnt_l < MIN (4, exponent))
+	  count_trailing_zeros (cnt_l, p.tmp[0]);
+	  if (cnt_l < MIN (4, p.exponent))
 	    {
-	      cy = __mpn_lshift (frac, tmp, tmpsize,
-				 BITS_PER_MP_LIMB - MIN (4, exponent));
+	      cy = __mpn_lshift (p.frac, p.tmp, p.tmpsize,
+				 BITS_PER_MP_LIMB - MIN (4, p.exponent));
 	      if (cy != 0)
-		frac[tmpsize++] = cy;
+		p.frac[p.tmpsize++] = cy;
 	    }
 	  else
-	    (void) __mpn_rshift (frac, tmp, tmpsize, MIN (4, exponent));
-	  fracsize = tmpsize;
+	    (void) __mpn_rshift (p.frac, p.tmp, p.tmpsize, MIN (4, p.exponent));
+	  p.fracsize = p.tmpsize;
 	  exp10 |= 1;
-	  assert (frac[fracsize - 1] < 10);
+	  assert (p.frac[p.fracsize - 1] < 10);
 	}
-      exponent = exp10;
+      p.exponent = exp10;
     }
   else
     {
@@ -793,13 +799,13 @@  ___printf_fp (FILE *fp,
 	 numbers are in the range of 1.0 <= |fp| < 8.0.  We simply
 	 shift it to the right place and divide it by 1.0 to get the
 	 leading digit.	 (Of course this division is not really made.)	*/
-      assert (0 <= exponent && exponent < 3 &&
-	      exponent + to_shift < BITS_PER_MP_LIMB);
+      assert (0 <= p.exponent && p.exponent < 3 &&
+	      p.exponent + to_shift < BITS_PER_MP_LIMB);
 
       /* Now shift the input value to its right place.	*/
-      cy = __mpn_lshift (frac, fp_input, fracsize, (exponent + to_shift));
-      frac[fracsize++] = cy;
-      exponent = 0;
+      cy = __mpn_lshift (p.frac, fp_input, p.fracsize, (p.exponent + to_shift));
+      p.frac[p.fracsize++] = cy;
+      p.exponent = 0;
     }
 
   {
@@ -817,7 +823,7 @@  ___printf_fp (FILE *fp,
 
     if (spec == 'e')
       {
-	type = info->spec;
+	p.type = info->spec;
 	intdig_max = 1;
 	fracdig_min = fracdig_max = info->prec < 0 ? 6 : info->prec;
 	chars_needed = 1 + 1 + (size_t) fracdig_max + 1 + 1 + 4;
@@ -827,15 +833,15 @@  ___printf_fp (FILE *fp,
       }
     else if (spec == 'f')
       {
-	type = 'f';
+	p.type = 'f';
 	fracdig_min = fracdig_max = info->prec < 0 ? 6 : info->prec;
 	dig_max = INT_MAX;		/* Unlimited.  */
 	significant = 1;		/* Does not matter here.  */
-	if (expsign == 0)
+	if (p.expsign == 0)
 	  {
-	    intdig_max = exponent + 1;
+	    intdig_max = p.exponent + 1;
 	    /* This can be really big!	*/  /* XXX Maybe malloc if too big? */
-	    chars_needed = (size_t) exponent + 1 + 1 + (size_t) fracdig_max;
+	    chars_needed = (size_t) p.exponent + 1 + 1 + (size_t) fracdig_max;
 	  }
 	else
 	  {
@@ -846,27 +852,27 @@  ___printf_fp (FILE *fp,
     else
       {
 	dig_max = info->prec < 0 ? 6 : (info->prec == 0 ? 1 : info->prec);
-	if ((expsign == 0 && exponent >= dig_max)
-	    || (expsign != 0 && exponent > 4))
+	if ((p.expsign == 0 && p.exponent >= dig_max)
+	    || (p.expsign != 0 && p.exponent > 4))
 	  {
 	    if ('g' - 'G' == 'e' - 'E')
-	      type = 'E' + (info->spec - 'G');
+	      p.type = 'E' + (info->spec - 'G');
 	    else
-	      type = isupper (info->spec) ? 'E' : 'e';
+	      p.type = isupper (info->spec) ? 'E' : 'e';
 	    fracdig_max = dig_max - 1;
 	    intdig_max = 1;
 	    chars_needed = 1 + 1 + (size_t) fracdig_max + 1 + 1 + 4;
 	  }
 	else
 	  {
-	    type = 'f';
-	    intdig_max = expsign == 0 ? exponent + 1 : 0;
+	    p.type = 'f';
+	    intdig_max = p.expsign == 0 ? p.exponent + 1 : 0;
 	    fracdig_max = dig_max - intdig_max;
 	    /* We need space for the significant digits and perhaps
 	       for leading zeros when < 1.0.  The number of leading
 	       zeros can be as many as would be required for
 	       exponential notation with a negative two-digit
-	       exponent, which is 4.  */
+	       p.exponent, which is 4.  */
 	    chars_needed = (size_t) dig_max + 1 + 4;
 	  }
 	fracdig_min = info->alt ? fracdig_max : 0;
@@ -908,26 +914,26 @@  ___printf_fp (FILE *fp,
     wcp = wstartp = wbuffer + 2;	/* Let room for rounding.  */
 
     /* Do the real work: put digits in allocated buffer.  */
-    if (expsign == 0 || type != 'f')
+    if (p.expsign == 0 || p.type != 'f')
       {
-	assert (expsign == 0 || intdig_max == 1);
+	assert (p.expsign == 0 || intdig_max == 1);
 	while (intdig_no < intdig_max)
 	  {
 	    ++intdig_no;
-	    *wcp++ = hack_digit ();
+	    *wcp++ = hack_digit (&p);
 	  }
 	significant = 1;
 	if (info->alt
 	    || fracdig_min > 0
-	    || (fracdig_max > 0 && (fracsize > 1 || frac[0] != 0)))
+	    || (fracdig_max > 0 && (p.fracsize > 1 || p.frac[0] != 0)))
 	  *wcp++ = decimalwc;
       }
     else
       {
-	/* |fp| < 1.0 and the selected type is 'f', so put "0."
+	/* |fp| < 1.0 and the selected p.type is 'f', so put "0."
 	   in the buffer.  */
 	*wcp++ = L'0';
-	--exponent;
+	--p.exponent;
 	*wcp++ = decimalwc;
       }
 
@@ -935,10 +941,10 @@  ___printf_fp (FILE *fp,
     int fracdig_no = 0;
     int added_zeros = 0;
     while (fracdig_no < fracdig_min + added_zeros
-	   || (fracdig_no < fracdig_max && (fracsize > 1 || frac[0] != 0)))
+	   || (fracdig_no < fracdig_max && (p.fracsize > 1 || p.frac[0] != 0)))
       {
 	++fracdig_no;
-	*wcp = hack_digit ();
+	*wcp = hack_digit (&p);
 	if (*wcp++ != L'0')
 	  significant = 1;
 	else if (significant == 0)
@@ -951,19 +957,19 @@  ___printf_fp (FILE *fp,
 
     /* Do rounding.  */
     wchar_t last_digit = wcp[-1] != decimalwc ? wcp[-1] : wcp[-2];
-    wchar_t next_digit = hack_digit ();
+    wchar_t next_digit = hack_digit (&p);
     bool more_bits;
     if (next_digit != L'0' && next_digit != L'5')
       more_bits = true;
-    else if (fracsize == 1 && frac[0] == 0)
+    else if (p.fracsize == 1 && p.frac[0] == 0)
       /* Rest of the number is zero.  */
       more_bits = false;
-    else if (scalesize == 0)
+    else if (p.scalesize == 0)
       {
 	/* Here we have to see whether all limbs are zero since no
 	   normalization happened.  */
-	size_t lcnt = fracsize;
-	while (lcnt >= 1 && frac[lcnt - 1] == 0)
+	size_t lcnt = p.fracsize;
+	while (lcnt >= 1 && p.frac[lcnt - 1] == 0)
 	  --lcnt;
 	more_bits = lcnt > 0;
       }
@@ -990,7 +996,7 @@  ___printf_fp (FILE *fp,
 	    if (*wtp != decimalwc)
 	      /* Round up.  */
 	      (*wtp)++;
-	    else if (__builtin_expect (spec == 'g' && type == 'f' && info->alt
+	    else if (__builtin_expect (spec == 'g' && p.type == 'f' && info->alt
 				       && wtp == wstartp + 1
 				       && wstartp[0] == L'0',
 				       0))
@@ -1015,20 +1021,20 @@  ___printf_fp (FILE *fp,
 	    else
 	      /* It is more critical.  All digits were 9's.  */
 	      {
-		if (type != 'f')
+		if (p.type != 'f')
 		  {
 		    *wstartp = '1';
-		    exponent += expsign == 0 ? 1 : -1;
+		    p.exponent += p.expsign == 0 ? 1 : -1;
 
-		    /* The above exponent adjustment could lead to 1.0e-00,
-		       e.g. for 0.999999999.  Make sure exponent 0 always
+		    /* The above p.exponent adjustment could lead to 1.0e-00,
+		       e.g. for 0.999999999.  Make sure p.exponent 0 always
 		       uses + sign.  */
-		    if (exponent == 0)
-		      expsign = 0;
+		    if (p.exponent == 0)
+		      p.expsign = 0;
 		  }
 		else if (intdig_no == dig_max)
 		  {
-		    /* This is the case where for type %g the number fits
+		    /* This is the case where for p.type %g the number fits
 		       really in the range for %f output but after rounding
 		       the number of digits is too big.	 */
 		    *--wstartp = decimalwc;
@@ -1044,9 +1050,9 @@  ___printf_fp (FILE *fp,
 		    fracdig_no += intdig_no;
 		    intdig_no = 1;
 		    fracdig_max = intdig_max - intdig_no;
-		    ++exponent;
-		    /* Now we must print the exponent.	*/
-		    type = isupper (info->spec) ? 'E' : 'e';
+		    ++p.exponent;
+		    /* Now we must print the p.exponent.	*/
+		    p.type = isupper (info->spec) ? 'E' : 'e';
 		  }
 		else
 		  {
@@ -1091,14 +1097,14 @@  ___printf_fp (FILE *fp,
 			    ngroups);
       }
 
-    /* Write the exponent if it is needed.  */
-    if (type != 'f')
+    /* Write the p.exponent if it is needed.  */
+    if (p.type != 'f')
       {
-	if (__glibc_unlikely (expsign != 0 && exponent == 4 && spec == 'g'))
+	if (__glibc_unlikely (p.expsign != 0 && p.exponent == 4 && spec == 'g'))
 	  {
-	    /* This is another special case.  The exponent of the number is
+	    /* This is another special case.  The p.exponent of the number is
 	       really smaller than -4, which requires the 'e'/'E' format.
-	       But after rounding the number has an exponent of -4.  */
+	       But after rounding the number has an p.exponent of -4.  */
 	    assert (wcp >= wstartp + 1);
 	    assert (wstartp[0] == L'1');
 	    __wmemcpy (wstartp, L"0.0001", 6);
@@ -1113,26 +1119,26 @@  ___printf_fp (FILE *fp,
 	  }
 	else
 	  {
-	    *wcp++ = (wchar_t) type;
-	    *wcp++ = expsign ? L'-' : L'+';
+	    *wcp++ = (wchar_t) p.type;
+	    *wcp++ = p.expsign ? L'-' : L'+';
 
-	    /* Find the magnitude of the exponent.	*/
+	    /* Find the magnitude of the p.exponent.	*/
 	    expscale = 10;
-	    while (expscale <= exponent)
+	    while (expscale <= p.exponent)
 	      expscale *= 10;
 
-	    if (exponent < 10)
+	    if (p.exponent < 10)
 	      /* Exponent always has at least two digits.  */
 	      *wcp++ = L'0';
 	    else
 	      do
 		{
 		  expscale /= 10;
-		  *wcp++ = L'0' + (exponent / expscale);
-		  exponent %= expscale;
+		  *wcp++ = L'0' + (p.exponent / expscale);
+		  p.exponent %= expscale;
 		}
 	      while (expscale > 10);
-	    *wcp++ = L'0' + exponent;
+	    *wcp++ = L'0' + p.exponent;
 	  }
       }