[flang] Interpret 'Q' exponent letter as kind=16 even on x86 (llvm#124158)

The compiler was interpreting 'Q' as an exponent letter in a literal
real constant as meaning real(kind=10) on x86-64, which is the legacy
80387 80-bit extended precision floating-point type. It turns out that
'Q' means kind=16 with all other compilers, even for x86-64 targets.
Change to conform.

Author: klausler

flang/lib/Common/default-kinds.cpp

@@ -11,11 +11,7 @@
 
 namespace Fortran::common {
 
-IntrinsicTypeDefaultKinds::IntrinsicTypeDefaultKinds() {
-#if __x86_64__
-  quadPrecisionKind_ = 10;
-#endif
-}
+IntrinsicTypeDefaultKinds::IntrinsicTypeDefaultKinds() {}
 
 IntrinsicTypeDefaultKinds &IntrinsicTypeDefaultKinds::set_defaultIntegerKind(
     int k) {

flang/lib/Frontend/CompilerInstance.cpp

@@ -153,9 +153,6 @@ bool CompilerInstance::executeAction(FrontendAction &act) {
   CompilerInvocation &invoc = this->getInvocation();
 
   llvm::Triple targetTriple{llvm::Triple(invoc.getTargetOpts().triple)};
-  if (targetTriple.getArch() == llvm::Triple::ArchType::x86_64) {
-    invoc.getDefaultKinds().set_quadPrecisionKind(10);
-  }
 
   // Set some sane defaults for the frontend.
   invoc.setDefaultFortranOpts();

flang/test/Semantics/kinds04_q10.f90

@@ -1,24 +1,19 @@
-! RUN: %python %S/test_errors.py %s %flang_fc1 -triple x86_64-unknown-linux-gnu
+! RUN: %python %S/test_errors.py %s %flang_fc1
 ! C716 If both kind-param and exponent-letter appear, exponent-letter
 ! shall be E. (As an extension we also allow an exponent-letter which matches
 ! the kind-param)
 ! C717 The value of kind-param shall specify an approximation method that
 ! exists on the processor.
-!
-! This test is for x86_64, where exponent-letter 'q' is for
-! 10-byte extended precision
-! UNSUPPORTED: system-windows, system-aix
-! REQUIRES: x86-registered-target
 
 subroutine s(var)
   real :: realvar1 = 4.0E6_4
   real :: realvar2 = 4.0D6
   real :: realvar3 = 4.0Q6
   !PORTABILITY: Explicit kind parameter together with non-'E' exponent letter is not standard
   real :: realvar4 = 4.0D6_8
-  !PORTABILITY: Explicit kind parameter together with non-'E' exponent letter is not standard
-  real :: realvar5 = 4.0Q6_10
   !WARNING: Explicit kind parameter on real constant disagrees with exponent letter 'q'
+  real :: realvar5 = 4.0Q6_10
+  !PORTABILITY: Explicit kind parameter together with non-'E' exponent letter is not standard
   real :: realvar6 = 4.0Q6_16
   real :: realvar7 = 4.0E6_8
   real :: realvar8 = 4.0E6_10
@@ -31,7 +26,7 @@ subroutine s(var)
   double precision :: doublevar3 = 4.0Q6
   !PORTABILITY: Explicit kind parameter together with non-'E' exponent letter is not standard
   double precision :: doublevar4 = 4.0D6_8
-  !WARNING: Explicit kind parameter on real constant disagrees with exponent letter 'q'
+  !PORTABILITY: Explicit kind parameter together with non-'E' exponent letter is not standard
   double precision :: doublevar5 = 4.0Q6_16
   double precision :: doublevar6 = 4.0E6_8
   double precision :: doublevar7 = 4.0E6_10