Fix Cast FP32 to Int32 Overflow

- With input of 2147483648.00, the output overflows to -2147483648
- The root cause is the following:
  - std::rint still returns float, the existing implementation is
    forcing a cast from that float to int32_t
  - when the input is over INT32_MAX, the output right after rint will
    overflow which casues the clipplings later to be ineffective
- Instead, perform the range check before rint

Signed-off-by: Jerry Ge <jerry.ge@arm.com>
Change-Id: Ib5a8cfd98aea17e326f8b11097beeb2d2b3efac9

1 files changed, 6 insertions, 2 deletions

diff --git a/reference_model/src/ops/type_conversion.cc b/reference_model/src/ops/type_conversion.cc
index 0135d1b..17abaf7 100644
--- a/reference_model/src/ops/type_conversion.cc
+++ b/reference_model/src/ops/type_conversion.cc
@@ -506,9 +506,13 @@ CastHelper<TOSA_REF_TYPE_FP32, OutDtype>::CastHelper()
 {
     // fp32 data converted to integer
     fcn = [](float in) -> OutEigenType {
+        if (in >= float(OutMax))
+            return OutMax;
+
+        if (in <= float(OutMin))
+            return OutMin;
+
         OutEigenType out = std::rint(in);
-        out              = std::max<OutEigenType>(out, OutMin);
-        out              = std::min<OutEigenType>(out, OutMax);
         return out;
     };
 }