Revert r248483, r242546, r242545, and r242409 - absdiff intrinsics

After much discussion, ending here:

  http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151123/315620.html

it has been decided that, instead of having the vectorizer directly generate
special absdiff and horizontal-add intrinsics, we'll recognize the relevant
reduction patterns during CodeGen. Accordingly, these intrinsics are not needed
(the operations they represent can be pattern matched, as is already done in
some backends). Thus, we're backing these out in favor of the current
development work.

r248483 - Codegen: Fix llvm.*absdiff semantic.
r242546 - [ARM] Use [SU]ABSDIFF nodes instead of intrinsics for VABD/VABA
r242545 - [AArch64] Use [SU]ABSDIFF nodes instead of intrinsics for ABD/ABA
r242409 - [Codegen] Add intrinsics 'absdiff' and corresponding SDNodes for absolute difference operation

llvm-svn: 255387

1 files changed, 0 insertions, 62 deletions

diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 7f1a97428ee..58198f7af7d 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -11217,68 +11217,6 @@ Examples:
 
       %r2 = call float @llvm.fmuladd.f32(float %a, float %b, float %c) ; yields float:r2 = (a * b) + c
 
-
-'``llvm.uabsdiff.*``' and '``llvm.sabsdiff.*``' Intrinsics
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Syntax:
-"""""""
-This is an overloaded intrinsic. The loaded data is a vector of any integer bit width.
-
-.. code-block:: llvm
-
-      declare <4 x integer> @llvm.uabsdiff.v4i32(<4 x integer> %a, <4 x integer> %b)
-
-
-Overview:
-"""""""""
-
-The ``llvm.uabsdiff`` intrinsic returns a vector result of the absolute difference
-of the two operands, treating them both as unsigned integers. The intermediate
-calculations are computed using infinitely precise unsigned arithmetic. The final
-result will be truncated to the given type.
-
-The ``llvm.sabsdiff`` intrinsic returns a vector result of the absolute difference of
-the two operands, treating them both as signed integers. If the result overflows, the
-behavior is undefined.
-
-.. note::
-
-    These intrinsics are primarily used during the code generation stage of compilation.
-    They are generated by compiler passes such as the Loop and SLP vectorizers. It is not
-    recommended for users to create them manually.
-
-Arguments:
-""""""""""
-
-Both intrinsics take two integer of the same bitwidth.
-
-Semantics:
-""""""""""
-
-The expression::
-
-    call <4 x i32> @llvm.uabsdiff.v4i32(<4 x i32> %a, <4 x i32> %b)
-
-is equivalent to::
-
-    %1 = zext <4 x i32> %a to <4 x i64>
-    %2 = zext <4 x i32> %b to <4 x i64>
-    %sub = sub <4 x i64> %1, %2
-    %trunc = trunc <4 x i64> to <4 x i32>
-
-and the expression::
-
-    call <4 x i32> @llvm.sabsdiff.v4i32(<4 x i32> %a, <4 x i32> %b)
-
-is equivalent to::
-
-    %sub = sub nsw <4 x i32> %a, %b
-    %ispos = icmp sge <4 x i32> %sub, zeroinitializer
-    %neg = sub nsw <4 x i32> zeroinitializer, %sub
-    %1 = select <4 x i1> %ispos, <4 x i32> %sub, <4 x i32> %neg
-
-
 Half Precision Floating Point Intrinsics
 ----------------------------------------