[PATCH] D63782: [FPEnv] Add fptosi and fptoui constrained intrinsics

Pengfei Wang via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu Aug 1 01:56:41 PDT 2019


pengfei added inline comments.


================
Comment at: include/llvm/CodeGen/ISDOpcodes.h:307
+    /// unsigned integer. These have the same semantics as fptosi and fptoui 
+    /// in IR. If the FP value cannot fit in the integer type, the results are
+    /// undefined.
----------------
kpn wrote:
> craig.topper wrote:
> > Is this what we want from a strict implementation. "icc -fp-model=strict" goes out of its way to generate an invalid exception when the input type doesn't fit and the hardware can't generate an exception on its own. https://godbolt.org/z/ABU80i
> No, I don't think this is what we want. I'll remove that sentence.
I don't understand the behavior of icc here. SDM says this instruction can raise floating-point invalid exception when the result out of range. Why icc add the code to raise another divz exception?


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https://reviews.llvm.org/D63782





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