[flang] Allow omission of comma in FORMAT(1PE5.2) in runtime

[klausler]

Summary

A comma is not required between a scale factor and a following
data edit descriptor (C1302).

[PeteSteinfeld]

All builds, tests, and looks good.

flang/runtime/format-implementation.h

if (ch == '(') {
         context.SignalError(
             IostatErrorInFormat, "Invalid width on Hollerith in FORMAT");
         return 0;
       }
       context.Emit(format_ + offset_, static_cast<std::size_t>(*repeat));
       offset_ += *repeat;
     } else if (ch >= 'A' && ch <= 'Z') {
       int start{offset_ - 1};
-      CharType next{Capitalize(PeekNext())};
-      if (next >= 'A' && next <= 'Z') {
+      CharType next{'\0'};
+      if (ch != 'P') { // 1PE5.2 - comma not required (C1302)
+        CharType peek{Capitalize(PeekNext())};
+        if (peek >= 'A' && peek <= 'Z') {
+          next = peek;
           ++offset_;
-      } else {
-        next = '\0';
+        }
       }
       if (ch == 'E' ||
           (!next &&
               (ch == 'A' || ch == 'I' || ch == 'B' || ch == 'O' || ch == 'Z' ||
                   ch == 'F' || ch == 'D' || ch == 'G' || ch == 'L'))) {
         // Data edit descriptor found
         offset_ = start;
         return repeat && *repeat > 0 ? *repeat : 1;

flang/unittests/Runtime/hello.cpp

static const char *zeroes[][2]{
       {"(DC,F32.17,';')", "             0,00000000000000000;"},
       {"(DC,G32.17,';')", "          0,0000000000000000    ;"},
       {"(D32.17,';')", "         0.00000000000000000D+00;"},
       {"(E32.17E1,';')", "          0.00000000000000000E+0;"},
       {"(G32.17E1,';')", "           0.0000000000000000   ;"},
       {"(E32.17E0,';')", "          0.00000000000000000E+0;"},
       {"(G32.17E0,';')", "          0.0000000000000000    ;"},
       {"(1P,E32.17,';')", "         0.00000000000000000E+00;"},
+      {"(1PE32.17,';')", "         0.00000000000000000E+00;"}, // no comma
       {"(1P,F32.17,';')", "             0.00000000000000000;"},
       {"(1P,G32.17,';')", "          0.0000000000000000    ;"},
       {"(2P,E32.17,';')", "         00.0000000000000000E+00;"},
       {"(-1P,E32.17,';')", "         0.00000000000000000E+00;"},
       {"(G0,';')", "0.;"}, {}};
   for (int j{0}; zeroes[j][0]; ++j) {
     realTest(zeroes[j][0], 0.0, zeroes[j][1]);
   }
 
   static const char *ones[][2]{
       {"(E32.17,';')", "         0.10000000000000000E+01;"},
       {"(F32.17,';')", "             1.00000000000000000;"},
       {"(G32.17,';')", "          1.0000000000000000    ;"},
       {"(E32.17E1,';')", "          0.10000000000000000E+1;"},
       {"(G32.17E1,';')", "           1.0000000000000000   ;"},
       {"(E32.17E0,';')", "          0.10000000000000000E+1;"},
       {"(G32.17E0,';')", "          1.0000000000000000    ;"},
       {"(E32.17E4,';')", "       0.10000000000000000E+0001;"},
       {"(G32.17E4,';')", "        1.0000000000000000      ;"},
       {"(1P,E32.17,';')", "         1.00000000000000000E+00;"},
+      {"(1PE32.17,';')", "         1.00000000000000000E+00;"}, // no comma
       {"(1P,F32.17,';')", "             0.10000000000000000;"},
       {"(1P,G32.17,';')", "          1.0000000000000000    ;"},
       {"(ES32.17,';')", "         1.00000000000000000E+00;"},
       {"(2P,E32.17,';')", "         10.0000000000000000E-01;"},
       {"(2P,G32.17,';')", "          1.0000000000000000    ;"},
       {"(-1P,E32.17,';')", "         0.01000000000000000E+02;"},
       {"(-1P,G32.17,';')", "          1.0000000000000000    ;"},
       {"(G0,';')", "1.;"}, {}};