grok_bin_oct_hex: Unroll loop one more iteration

Earlier I was confused when I thought that 7 hex digits were the max
before we needed to start worrying about overflow.  That's true for
signed results where everything above 7FFF_FFFF won't fit in a 32-bit
signed integer.  But these functions return unsigned, and so any 8
digits will fit in a 32-bit word.

1 files changed, 8 insertions, 4 deletions

diff --git a/numeric.c b/numeric.c
index 6e5bce73e2..58f5a085bc 100644
--- a/numeric.c
+++ b/numeric.c
@@ -423,9 +423,8 @@ Perl_grok_bin_oct_hex(pTHX_ const char *start,
 
     s = s0; /* s0 potentially advanced from 'start' */
 
-    /* Unroll the loop so that the first 7 digits are branchless except for the
-     * switch.  An eighth one could overflow a 32 bit word.  This should
-     * completely handle the common case without needing extra checks */
+    /* Unroll the loop so that the first 8 digits are branchless except for the
+     * switch.  A ninth one overflows a 32 bit word. */
     switch (len) {
       case 0:
           return 0;
@@ -434,6 +433,11 @@ Perl_grok_bin_oct_hex(pTHX_ const char *start,
           value = (value << shift) | XDIGIT_VALUE(*s);
           s++;
           /* FALLTHROUGH */
+      case 7:
+          if (! _generic_isCC(*s, class_bit))  break;
+          value = (value << shift) | XDIGIT_VALUE(*s);
+          s++;
+          /* FALLTHROUGH */
       case 6:
           if (! _generic_isCC(*s, class_bit))  break;
           value = (value << shift) | XDIGIT_VALUE(*s);
@@ -463,7 +467,7 @@ Perl_grok_bin_oct_hex(pTHX_ const char *start,
           if (! _generic_isCC(*s, class_bit))  break;
           value = (value << shift) | XDIGIT_VALUE(*s);
 
-          if (LIKELY(len <= 7)) {
+          if (LIKELY(len <= 8)) {
               return value;
           }