Re-land r15232 with a warnings fix:

base/third_party/dmg_fp/gcc_warnings.patch

 Index: dtoa.cc
 --- dtoa.cc    (old copy)
 +++ dtoa.cc    (working copy)
-@@ -172,6 +172,10 @@
+@@ -179,6 +179,9 @@
+  *     used for input more than STRTOD_DIGLIM digits long (default 40).
   */
  
- #define IEEE_8087
-+#if defined(__GNUC__)
-+// Make gcc 4.3+ warnings about parentheses non-fatal warnings.
-+#pragma GCC diagnostic warning "-Wparentheses"
-+#endif
- 
++#define IEEE_8087
++#define NO_HEX_FP
++
  #ifndef Long
  #define Long long
-@@ -515,7 +519,7 @@ Balloc
+ #endif
+@@ -280,9 +283,7 @@
+ #include "math.h"
  #endif
  
-        ACQUIRE_DTOA_LOCK(0);
--       if (rv = freelist[k]) {
-+       if ((rv = freelist[k])) {
-                freelist[k] = rv->next;
-                }
-        else {
-@@ -794,7 +798,7 @@ mult
-        xc0 = c->x;
- #ifdef ULLong
-        for(; xb < xbe; xc0++) {
--               if (y = *xb++) {
-+               if ((y = *xb++)) {
-                        x = xa;
-                        xc = xc0;
-                        carry = 0;
-@@ -876,7 +880,7 @@ pow5mult
-        int i;
-        static int p05[3] = { 5, 25, 125 };
+-#ifdef __cplusplus
+-extern "C" {
+-#endif
++namespace dmg_fp {
  
--       if (i = k & 3)
-+       if ((i = k & 3))
-                b = multadd(b, p05[i-1], 0);
+ #ifndef CONST
+ #ifdef KR_headers
+@@ -511,11 +512,9 @@
  
-        if (!(k >>= 2))
-@@ -957,7 +961,7 @@ lshift
-                        z = *x++ >> k1;
-                        }
-                        while(x < xe);
--               if (*x1 = z)
-+               if ((*x1 = z))
-                        ++n1;
-                }
- #else
-@@ -1259,12 +1263,12 @@ d2b
-        z |= Exp_msk11;
- #endif
- #else
--       if (de = (int)(d0 >> Exp_shift))
-+       if ((de = (int)(d0 >> Exp_shift)))
-                z |= Exp_msk1;
- #endif
- #ifdef Pack_32
--       if (y = d1) {
--               if (k = lo0bits(&y)) {
-+       if ((y = d1)) {
-+               if ((k = lo0bits(&y))) {
-                        x[0] = y | z << 32 - k;
-                        z >>= k;
-                        }
-@@ -1452,13 +1456,13 @@ match
+ #define Kmax 7
+ 
+-#ifdef __cplusplus
+-extern "C" double strtod(const char *s00, char **se);
+-extern "C" char *dtoa(double d, int mode, int ndigits,
++double strtod(const char *s00, char **se);
++char *dtoa(double d, int mode, int ndigits,
+                        int *decpt, int *sign, char **rve);
+-#endif
+ 
+  struct
+ Bigint {
+@@ -1527,7 +1526,7 @@
  #ifdef KR_headers
         (sp, t) char **sp, *t;
  #else
 -       (CONST char **sp, char *t)
 +       (CONST char **sp, CONST char *t)
  #endif
  {
         int c, d;
-        CONST char *s = *sp;
- 
--       while(d = *t++) {
-+       while((d = *t++)) {
-                if ((c = *++s) >= 'A' && c <= 'Z')
-                        c += 'a' - 'A';
-                if (c != d)
-@@ -1490,7 +1494,7 @@ hexnan
-                ++s;
-        if (s[1] == '0' && (s[2] == 'x' || s[2] == 'X'))
-                s += 2;
--       while(c = *(CONST unsigned char*)++s) {
-+       while((c = *(CONST unsigned char*)++s)) {
-                if (c >= '0' && c <= '9')
-                        c -= '0';
-                else if (c >= 'a' && c <= 'f')
-@@ -1518,7 +1522,7 @@ hexnan
-                                        *sp = s + 1;
-                                        break;
-                                        }
--                               } while(c = *++s);
-+                               } while((c = *++s));
-                        break;
-                        }
- #endif
-@@ -1852,7 +1856,7 @@ strtod
-        /* Get starting approximation = rv * 10**e1 */
- 
-        if (e1 > 0) {
--               if (i = e1 & 15)
-+               if ((i = e1 & 15))
-                        dval(rv) *= tens[i];
-                if (e1 &= ~15) {
-                        if (e1 > DBL_MAX_10_EXP) {
-@@ -1912,7 +1916,7 @@ strtod
-                }
-        else if (e1 < 0) {
-                e1 = -e1;
--               if (i = e1 & 15)
-+               if ((i = e1 & 15))
-                        dval(rv) /= tens[i];
-                if (e1 >>= 4) {
-                        if (e1 >= 1 << n_bigtens)
-@@ -2580,7 +2584,7 @@ rv_alloc(int i)
+@@ -2234,7 +2234,7 @@ bigcomp
+        nd = bc->nd;
+        nd0 = bc->nd0;
+        p5 = nd + bc->e0 - 1;
+-       speccase = 0;
++       dd = speccase = 0;
+ #ifndef Sudden_Underflow
+        if (rv->d == 0.) {      /* special case: value near underflow-to-zero */
+                                /* threshold was rounded to zero */
+@@ -3431,7 +3430,7 @@
  
         j = sizeof(ULong);
         for(k = 0;
 -               sizeof(Bigint) - sizeof(ULong) - sizeof(int) + j <= i;
 +               sizeof(Bigint) - sizeof(ULong) - sizeof(int) + j <= (size_t)i;
                 j <<= 1)
                         k++;
         r = (int*)Balloc(k);
-@@ -2596,13 +2600,13 @@ rv_alloc(int i)
+@@ -3447,7 +3446,7 @@
  #ifdef KR_headers
  nrv_alloc(s, rve, n) char *s, **rve; int n;
  #else
 -nrv_alloc(char *s, char **rve, int n)
 +nrv_alloc(CONST char *s, char **rve, int n)
  #endif
  {
         char *rv, *t;
- 
-        t = rv = rv_alloc(n);
--       while(*t = *s++) t++;
-+       while((*t = *s++)) t++;
-        if (rve)
-                *rve = t;
-        return rv;
-@@ -2707,7 +2711,7 @@ dtoa
-                to hold the suppressed trailing zeros.
-        */
- 
--       int bbits, b2, b5, be, dig, i, ieps, ilim, ilim0, ilim1,
-+       int bbits, b2, b5, be, dig, i, ieps, ilim = 0, ilim0, ilim1 = 0,
-                j, j1, k, k0, k_check, leftright, m2, m5, s2, s5,
-                spec_case, try_quick;
-        Long L;
-@@ -2792,7 +2796,7 @@ dtoa
- #ifdef Sudden_Underflow
-        i = (int)(word0(d) >> Exp_shift1 & (Exp_mask>>Exp_shift1));
- #else
--       if (i = (int)(word0(d) >> Exp_shift1 & (Exp_mask>>Exp_shift1))) {
-+       if ((i = (int)(word0(d) >> Exp_shift1 & (Exp_mask>>Exp_shift1)))) {
- #endif
-                dval(d2) = dval(d);
-                word0(d2) &= Frac_mask1;
-@@ -2946,7 +2950,7 @@ dtoa
-                                        }
-                        dval(d) /= ds;
-                        }
--               else if (j1 = -k) {
-+               else if ((j1 = -k)) {
-                        dval(d) *= tens[j1 & 0xf];
-                        for(j = j1 >> 4; j; j >>= 1, i++)
-                                if (j & 1) {
-@@ -3107,7 +3111,7 @@ dtoa
-                                Bfree(b);
-                                b = b1;
-                                }
--                       if (j = b5 - m5)
-+                       if ((j = b5 - m5))
-                                b = pow5mult(b, j);
-                        }
-                else
-@@ -3145,7 +3149,7 @@ dtoa
-         * can do shifts and ors to compute the numerator for q.
-         */
- #ifdef Pack_32
--       if (i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0x1f)
-+       if ((i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0x1f))
-                i = 32 - i;
- #else
-        if (i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0xf)
-@@ -3322,7 +3326,9 @@ dtoa
-                ++*s++;
-                }
-        else {
-+#ifdef Honor_FLT_ROUNDS
-  trimzeros:
-+#endif
-                while(*--s == '0');
-                s++;
-                }
+@@ -4202,6 +4201,5 @@
+                *rve = s;
+        return s0;
+        }
+-#ifdef __cplusplus
+-}
+-#endif
++
++}  // namespace dmg_fp
 Index: g_fmt.cc
 --- g_fmt.cc   (old copy)
 +++ g_fmt.cc   (new copy)
 @@ -46,14 +46,14 @@ g_fmt(register char *b, double x)
         if (sign)
                 *b++ = '-';
         if (decpt == 9999) /* Infinity or Nan */ {
 -               while(*b++ = *s++);
 +               while((*b++ = *s++));
                 goto done0;
@@ skipping 23 matching lines @@
 @@ -93,7 +93,9 @@ g_fmt(register char *b, double x)
                 }
   done0:
         freedtoa(s0);
 +#ifdef IGNORE_ZERO_SIGN
   done:
 +#endif
         return b0;
         }