[clang] [CIR][CodeGen] Upstream support for FP environments and RAII options (PR #179121)

[Hendrik Hübner via cfe-commits]

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@@ -1119,6 +1136,59 @@ void CIRGenFunction::emitNullInitialization(mlir::Location loc, Address destPtr,
   builder.createStore(loc, zeroValue, destPtr);
 }
 
+CIRGenFunction::CIRGenFPOptionsRAII::CIRGenFPOptionsRAII(CIRGenFunction &cgf,
+                                                         const clang::Expr *e)
+    : cgf(cgf) {
+  ConstructorHelper(e->getFPFeaturesInEffect(cgf.getLangOpts()));
+}
+
+CIRGenFunction::CIRGenFPOptionsRAII::CIRGenFPOptionsRAII(CIRGenFunction &cgf,
+                                                         FPOptions fpFeatures)
+    : cgf(cgf) {
+  ConstructorHelper(fpFeatures);
+}
+
+void CIRGenFunction::CIRGenFPOptionsRAII::ConstructorHelper(
+    FPOptions fpFeatures) {
+  oldFPFeatures = cgf.curFPFeatures;
+  cgf.curFPFeatures = fpFeatures;
+
+  oldExcept = cgf.builder.getDefaultConstrainedExcept();
+  oldRounding = cgf.builder.getDefaultConstrainedRounding();
+
+  if (oldFPFeatures == fpFeatures)
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HendrikHuebner wrote:

maybe check this first

https://github.com/llvm/llvm-project/pull/179121