Sync trunk and py3k versions of string formatting. Manual merge of r74219.

Objects/stringlib/formatter.h

@@ -920,6 +920,13 @@ format_float_internal(PyObject *value,
            format the result. We take care of that later. */
         type = 'g';
 
+#if PY_VERSION_HEX < 0x0301000
+    /* 'F' is the same as 'f', per the PEP */
+    /* This is no longer the case in 3.x */
+    if (type == 'F')
+        type = 'f';
+#endif
+
     val = PyFloat_AsDouble(value);
     if (val == -1.0 && PyErr_Occurred())
         goto done;
@@ -935,15 +942,8 @@ format_float_internal(PyObject *value,
 
 #if PY_VERSION_HEX < 0x03010000
     /* 3.1 no longer converts large 'f' to 'g'. */
-    if (fabs(val) >= 1e50)
-        switch (type) {
-        case 'f':
-            type = 'g';
-            break;
-        case 'F':
-            type = 'G';
-            break;
-        }
+    if ((type == 'f' || type == 'F') && fabs(val) >= 1e50)
+        type = 'g';
 #endif
 
     /* Cast "type", because if we're in unicode we need to pass a
@@ -1117,6 +1117,13 @@ format_complex_internal(PyObject *value,
            format the result. We take care of that later. */
         type = 'g';
 
+#if PY_VERSION_HEX < 0x03010000
+    /* This is no longer the case in 3.x */
+    /* 'F' is the same as 'f', per the PEP */
+    if (type == 'F')
+        type = 'f';
+#endif
+
     if (precision < 0)
         precision = default_precision;