[PATCH] D47851: [LangRef] fptosi and fptoui return poison on overflow.

[Eli Friedman via Phabricator via llvm-commits]

efriedma created this revision.
efriedma added reviewers: spatel, chandlerc, hfinkel, nlopes.

I think we assume poison, not undef, for certain transforms we currently do. In any case, we should clarify the language here.


Repository:
  rL LLVM

https://reviews.llvm.org/D47851

Files:
  docs/LangRef.rst


Index: docs/LangRef.rst
===================================================================
--- docs/LangRef.rst
+++ docs/LangRef.rst
@@ -3275,13 +3275,15 @@
     integer constant. TYPE must be a scalar or vector integer type. CST
     must be of scalar or vector floating-point type. Both CST and TYPE
     must be scalars, or vectors of the same number of elements. If the
-    value won't fit in the integer type, the results are undefined.
+    value won't fit in the integer type, the result is a
+    :ref:`poison value <poisonvalues>`.
 ``fptosi (CST to TYPE)``
     Convert a floating-point constant to the corresponding signed
     integer constant. TYPE must be a scalar or vector integer type. CST
     must be of scalar or vector floating-point type. Both CST and TYPE
     must be scalars, or vectors of the same number of elements. If the
-    value won't fit in the integer type, the results are undefined.
+    value won't fit in the integer type, the result is a
+    :ref:`poison value <poisonvalues>`.
 ``uitofp (CST to TYPE)``
     Convert an unsigned integer constant to the corresponding 
     floating-point constant. TYPE must be a scalar or vector floating-point
@@ -8764,8 +8766,8 @@
 
 The '``fptoui``' instruction converts its :ref:`floating-point
 <t_floating>` operand into the nearest (rounding towards zero)
-unsigned integer value. If the value cannot fit in ``ty2``, the results
-are undefined.
+unsigned integer value. If the value cannot fit in ``ty2``, the result
+is a :ref:`poison value <poisonvalues>`.
 
 Example:
 """"""""
@@ -8806,8 +8808,8 @@
 
 The '``fptosi``' instruction converts its :ref:`floating-point
 <t_floating>` operand into the nearest (rounding towards zero)
-signed integer value. If the value cannot fit in ``ty2``, the results
-are undefined.
+signed integer value. If the value cannot fit in ``ty2``, the result
+is a :ref:`poison value <poisonvalues>`.
 
 Example:
 """"""""


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