fpcmp: Allow decimal numbers ending with a period

After 8a84a50, fpcmp requires at least one post-decimal digit when
period present. This leads to incorrect comparison results for
628.pop2_s of SPEC2017 because this program outputs `65.` when the
Fortran compiler is flang while the reference output is `65.0`.

Author: SixWeining

tools/fpcmp.c

@@ -67,17 +67,13 @@ static const char *AdvanceNumber(const char *StartPos, const char *End) {
   // Decimal separator
   if (Pos < End && *Pos == '.') {
     ++Pos;
+    EndOfNumber = Pos;
 
-    // Post-decimal digits (require at least one when period present)
-    bool HasPostDecimalDigit = false;
+    // Post-decimal digits (optional)
     while (Pos < End && isDigitChar(*Pos)) {
-      HasPostDecimalDigit = true;
-
       ++Pos;
       EndOfNumber = Pos;
     }
-    if (!HasPostDecimalDigit)
-      return EndOfNumber;
   }
 
   // Require a valid number before the exponent.

tools/test/CMakeLists.txt

@@ -2,6 +2,10 @@
 # without the source directory.
 configure_file(test_not.py test_not.py
   COPYONLY)
+configure_file(fpcmp-input1 fpcmp-input1
+  COPYONLY)
+configure_file(fpcmp-input2 fpcmp-input2
+  COPYONLY)
 
 llvm_test_executable_no_test(ret1 ret1.c)
 add_dependencies(ret1 not)
@@ -19,6 +23,10 @@ add_dependencies(abrt not)
 llvm_test_run(EXECUTABLE "$<TARGET_FILE:not>" "--crash" "$<TARGET_FILE:abrt>")
 llvm_add_test_for_target(abrt)
 
+# Check that fpcmp can handle decimal numbers ending with a period correctly.
+llvm_test_run(EXECUTABLE "$<TARGET_FILE:fpcmp-target>" "-a" "0.03" "-r" "0.03" "-i" "%b/test/fpcmp-input1" "%b/test/fpcmp-input2")
+llvm_add_test_for_target(fpcmp-target)
+
 # Check that not passes environment variables to the called executable.
 find_package(Python COMPONENTS Interpreter)
 llvm_test_executable_no_test(check_env check_env.c)

tools/test/fpcmp-input1

@@ -0,0 +1,2 @@
+65.
+3.E-02

tools/test/fpcmp-input2

@@ -0,0 +1,2 @@
+65.0
+3.0E-02