================
@@ -1658,6 +1828,170 @@ mlir::Value
ScalarExprEmitter::VisitUnaryExprOrTypeTraitExpr(
cgf.cgm.UInt64Ty, e->EvaluateKnownConstInt(cgf.getContext())));
}
+/// Return true if the specified expression is cheap enough and
side-effect-free
+/// enough to evaluate unconditionally instead of conditionally. This is used
+/// to convert control flow into selects in some cases.
+/// TODO(cir): can be shared with LLVM codegen.
+static bool isCheapEnoughToEvaluateUnconditionally(const Expr *e,
+ CIRGenFunction &cgf) {
+ // Anything that is an integer or floating point constant is fine.
+ return e->IgnoreParens()->isEvaluatable(cgf.getContext());
----------------
andykaylor wrote:
We wouldn't want to speculatively evaluate constant foldable floating point
expressions if they might raise an exception. I don't think this handles that
correctly. We are a long way from having strict floating-point semantics in
CIR, but the classic codegen gets this wrong: https://godbolt.org/z/nvfT4WxK4
https://github.com/llvm/llvm-project/pull/138156
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