diff --git a/manifest b/manifest
index 06c6814c38..7fa7ebedf8 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Remove\sstill\smore\sunnecessary\sbranches\sfrom\ssqlite3AtoF().
-D 2016-04-27T02:35:03.572
+C More\ssimplification\sof\sthe\ssqlite3AtoF()\sroutine.\s\sAdd\sspecial\scomments\nto\sindicate\sbranches\sthat\sare\sfor\soptimization\spurposes\sonly\sand\sthat\sgive\nthe\scorrect\sanswer\seven\sif\salways\sor\snever\staken.
+D 2016-04-27T15:24:13.573
 F Makefile.in 9e816d0323e418fbc0f8b2c05fc14e0b3763d9e8
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 71b8b16cf9393f68e2e2035486ca104872558836
@@ -441,7 +441,7 @@ F src/treeview.c e4b41a37530a191579d3c53142cc44ee2eb99373
 F src/trigger.c e14840ee0c3e549e758ec9bf3e4146e166002280
 F src/update.c 3e67ab3c0814635f355fb1f8ab010a2b9e016e7d
 F src/utf.c 699001c79f28e48e9bcdf8a463da029ea660540c
-F src/util.c 562f7a85d933b7173a29e331deb28d85d6208f7c
+F src/util.c d0899604c30b4a9d493980aa7742eeda383fff6d
 F src/vacuum.c feb1eabb20987983d9350cad98299b21fa811f52
 F src/vdbe.c d3843a66d74a7696477ee5141e5eb9a7e5e2401c
 F src/vdbe.h 5591b5add447096e31288b5a0a78ec5d7b5c5170
@@ -1484,7 +1484,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P dd69e53cb077873171af5312c633ca185595bf31
-R 4f22b05e3bc28723a991a2f87c87962e
+P 3adfe9f3e6ce7cc09fcb570d9b65e830a96cac15
+R 676347b15924e075b34cabb43dd7e840
 U drh
-Z 439e39a464407086f87a7be758f8e1c8
+Z 680dc6a7c6e0d675cd4dc0c16abcab9d
diff --git a/manifest.uuid b/manifest.uuid
index 1f512c3c71..a6a5e1cabb 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-3adfe9f3e6ce7cc09fcb570d9b65e830a96cac15
\ No newline at end of file
+0065fe97cb8e5076acae1bf1560fd2f69dab9014
\ No newline at end of file
diff --git a/src/util.c b/src/util.c
index c85ae6a199..1f59a9f731 100644
--- a/src/util.c
+++ b/src/util.c
@@ -355,7 +355,7 @@ int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
   int eValid = 1;  /* True exponent is either not used or is well-formed */
   double result;
   int nDigits = 0;
-  int nonNum = 0;
+  int nonNum = 0;  /* True if input contains UTF16 with high byte non-zero */
 
   assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
   *pResult = 0.0;   /* Default return value, in case of an error */
@@ -368,7 +368,7 @@ int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
     assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
     for(i=3-enc; i<length && z[i]==0; i+=2){}
     nonNum = i<length;
-    zEnd = z+i+enc-3;
+    zEnd = &z[i^1];
     z += (enc&1);
   }
 
@@ -414,7 +414,12 @@ int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
   if( *z=='e' || *z=='E' ){
     z+=incr;
     eValid = 0;
-    if( z>=zEnd ) goto do_atof_calc;
+
+    /* This branch is needed to avoid a (harmless) buffer overread.  The 
+    ** special comment alerts the mutation tester that the correct answer
+    ** is obtained even if the branch is omitted */
+    if( z>=zEnd ) goto do_atof_calc;              /*PREVENTS-HARMLESS-OVERREAD*/
+
     /* get sign of exponent */
     if( *z=='-' ){
       esign = -1;
@@ -443,41 +448,51 @@ do_atof_calc:
     esign = 1;
   }
 
-  /* if 0 significand */
-  if( !s ) {
-    /* In the IEEE 754 standard, zero is signed.
-    ** Add the sign if we've seen at least one digit */
+  if( s==0 ) {
+    /* In the IEEE 754 standard, zero is signed. */
     result = sign<0 ? -(double)0 : (double)0;
   } else {
-    /* attempt to reduce exponent */
-    if( esign>0 ){
-      while( s<(LARGEST_INT64/10) && e>0 ) e--,s*=10;
-    }else{
-      while( !(s%10) && e>0 ) e--,s/=10;
+    /* Attempt to reduce exponent.
+    **
+    ** Branches that are not required for the correct answer but which only
+    ** help to obtain the correct answer faster are marked with special
+    ** comments, as a hint to the mutation tester.
+    */
+    while( e>0 ){                                       /*OPTIMIZATION-IF-TRUE*/
+      if( esign>0 ){
+        if( s>=(LARGEST_INT64/10) ) break;             /*OPTIMIZATION-IF-FALSE*/
+        s *= 10;
+      }else{
+        if( s%10!=0 ) break;                           /*OPTIMIZATION-IF-FALSE*/
+        s /= 10;
+      }
+      e--;
     }
 
     /* adjust the sign of significand */
     s = sign<0 ? -s : s;
 
-    /* if exponent, scale significand as appropriate
-    ** and store in result. */
-    if( e ){
+    if( e==0 ){                                         /*OPTIMIZATION-IF-TRUE*/
+      result = (double)s;
+    }else{
       LONGDOUBLE_TYPE scale = 1.0;
       /* attempt to handle extremely small/large numbers better */
-      if( e>307 && e<342 ){
-        while( e%308 ) { scale *= 1.0e+1; e -= 1; }
-        if( esign<0 ){
-          result = s / scale;
-          result /= 1.0e+308;
-        }else{
-          result = s * scale;
-          result *= 1.0e+308;
-        }
-      }else if( e>=342 ){
-        if( esign<0 ){
-          result = 0.0*s;
-        }else{
-          result = 1e308*1e308*s;  /* Infinity */
+      if( e>307 ){                                      /*OPTIMIZATION-IF-TRUE*/
+        if( e<342 ){                                    /*OPTIMIZATION-IF-TRUE*/
+          while( e%308 ) { scale *= 1.0e+1; e -= 1; }
+          if( esign<0 ){
+            result = s / scale;
+            result /= 1.0e+308;
+          }else{
+            result = s * scale;
+            result *= 1.0e+308;
+          }
+        }else{ assert( e>=342 );
+          if( esign<0 ){
+            result = 0.0*s;
+          }else{
+            result = 1e308*1e308*s;  /* Infinity */
+          }
         }
       }else{
         /* 1.0e+22 is the largest power of 10 than can be 
@@ -490,8 +505,6 @@ do_atof_calc:
           result = s * scale;
         }
       }
-    } else {
-      result = (double)s;
     }
   }
 
@@ -499,7 +512,7 @@ do_atof_calc:
   *pResult = result;
 
   /* return true if number and no extra non-whitespace chracters after */
-  return z>=zEnd && nDigits>0 && eValid && nonNum==0;
+  return z==zEnd && nDigits>0 && eValid && nonNum==0;
 #else
   return !sqlite3Atoi64(z, pResult, length, enc);
 #endif /* SQLITE_OMIT_FLOATING_POINT */