[PATCH] D55897: Add constrained fptrunc and fpext intrinsics

[Andy Kaylor via Phabricator via llvm-commits]

andrew.w.kaylor added inline comments.


================
Comment at: lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:2787
+  case ISD::STRICT_FP_ROUND:
+    Tmp1 = EmitStackConvert(Node->getOperand(1), 
+                            Node->getValueType(0),
----------------
Can this cause the wrong rounding mode to be used? For X86 targets I would guess it will result in an instruction that uses the runtime rounding mode, but I'm not sure we can count on that for all targets. Also, if the value being converted is a constant, might this get folded using the default rounding mode? And if it is a constant and we knew the rounding mode based on an argument to the intrinsic, we might want to fold it (though ideally that would have happened before this).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D55897/new/

https://reviews.llvm.org/D55897