Revert "[Clang] Reset FP options before function instantiations"

This reverts commit 98390cc.
It caused issue #63542.

Author: spavloff

clang/include/clang/Sema/Sema.h

@@ -710,12 +710,6 @@ class Sema final {
     return result;
   }
 
-  void resetFPOptions(FPOptions FPO) {
-    CurFPFeatures = FPO;
-    FpPragmaStack.Stack.clear();
-    FpPragmaStack.CurrentValue = FPO.getChangesFrom(FPOptions(LangOpts));
-  }
-
   // RAII object to push / pop sentinel slots for all MS #pragma stacks.
   // Actions should be performed only if we enter / exit a C++ method body.
   class PragmaStackSentinelRAII {
@@ -14007,8 +14001,6 @@ struct LateParsedTemplate {
   CachedTokens Toks;
   /// The template function declaration to be late parsed.
   Decl *D;
-  /// Floating-point options in the point of definition.
-  FPOptions FPO;
 };
 
 template <>

clang/lib/Parse/ParseTemplate.cpp

@@ -1742,10 +1742,6 @@ void Parser::ParseLateTemplatedFuncDef(LateParsedTemplate &LPT) {
       Actions.PushDeclContext(Actions.getCurScope(), DC);
   }
 
-  // Parsing should occur with empty FP pragma stack and FP options used in the
-  // point of the template definition.
-  Actions.resetFPOptions(LPT.FPO);
-
   assert(!LPT.Toks.empty() && "Empty body!");
 
   // Append the current token at the end of the new token stream so that it

clang/lib/Sema/SemaTemplate.cpp

@@ -11342,7 +11342,6 @@ void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
   // Take tokens to avoid allocations
   LPT->Toks.swap(Toks);
   LPT->D = FnD;
-  LPT->FPO = getCurFPFeatures();
   LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
 
   FD->setLateTemplateParsed(true);

clang/test/CodeGen/fp-template.cpp

@@ -15,40 +15,4 @@ float func_01(float x, float y) {
 // CHECK-SAME:  (float noundef %{{.*}}, float noundef %{{.*}}) #[[ATTR01:[0-9]+]]{{.*}} {
 // CHECK:       call float @llvm.experimental.constrained.fadd.f32
 
-
-template <typename Ty>
-Ty templ_02(Ty x, Ty y) {
-  return x + y;
-}
-
-#pragma STDC FENV_ROUND FE_UPWARD
-
-template <typename Ty>
-Ty templ_03(Ty x, Ty y) {
-  return x - y;
-}
-
-#pragma STDC FENV_ROUND FE_TONEAREST
-
-float func_02(float x, float y) {
-  return templ_02(x, y);
-}
-
-// CHECK-LABEL: define {{.*}} float @_Z8templ_02IfET_S0_S0_
-// CHECK:       %add = fadd float %0, %1
-
-float func_03(float x, float y) {
-  return templ_03(x, y);
-}
-
-// CHECK-LABEL: define {{.*}} float @_Z8templ_03IfET_S0_S0_
-// CHECK:       call float @llvm.experimental.constrained.fsub.f32({{.*}}, metadata !"round.upward", metadata !"fpexcept.ignore")
-
-
-// This pragma sets non-default rounding mode before delayed parsing occurs. It
-// is used to check that the parsing uses FP options defined by command line
-// options or by pragma before the template definition but not by this pragma.
-#pragma STDC FENV_ROUND FE_TOWARDZERO
-
-
 // CHECK: attributes #[[ATTR01]] = { {{.*}}strictfp