[clang] [CIR] Record -ffp-contract=fast as a per-op contract flag (PR #226334)

[Andy Kaylor via cfe-commits]

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@@ -51,10 +51,20 @@ CIRGenFunction::CIRGenFunction(CIRGenModule &cgm, CIRGenBuilderTy &builder,
   ehStack.setCGF(this);
   shouldEmitLifetimeMarkers = CodeGenUtils::shouldEmitLifetimeMarkers(
       cgm.getCodeGenOpts(), getContext().getLangOpts());
+  setFastMathFlags(curFPFeatures);
 }
 
 CIRGenFunction::~CIRGenFunction() {}
 
+void CIRGenFunction::setFastMathFlags(FPOptions fpFeatures) {
+  // TODO(cir): set the remaining fast-math flags.
+  assert(!cir::MissingFeatures::fastMathFlags());
+  cir::FastMathFlags flags = cir::FastMathFlags::none;
+  if (fpFeatures.allowFPContractAcrossStatement())
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andykaylor wrote:

Oh, I see. This is where the other fast-math flags would be set, but they are just being ignored. Is that just to limit the testing? It seems like we should just implement this properly all at once.

https://github.com/llvm/llvm-project/pull/226334