C++ API to shufflevector wants mask the same size as arg 1

[llvmbot]

Bugzilla Link	3260
Resolution	INVALID
Resolved on	Dec 23, 2008 10:02
Version	unspecified
OS	MacOS X
Reporter	LLVM Bugzilla Contributor

Extended Description

The documentation for shufflevector says that the mask can have a different length than the two first arguments (which will also be the size of the result).
But the C++ code in lib/VMCore/Instructions.cpp, line 1328 forces the mask to be the same length as argument 1.
Either the documentation or the C++ is wrong.

This is for LLVM 2.4 (bugzilla only lets me pick unspecified, seems like a bug).

[llvmbot]

You're looking at the current in-CVS documentation while using LLVM 2.4. According to llvm.org/releases/2.4/docs/LangRef.html, shufflevector is defined as:

"Overview:

"The 'shufflevector' instruction constructs a permutation of elements from two input vectors, returning a vector of the same type.
Arguments:

"The first two operands of a 'shufflevector' instruction are vectors with types that match each other and types that match the result of the instruction. The third argument is a shuffle mask, which has the same number of elements as the other vector type, but whose element type is always 'i32'.

"The shuffle mask operand is required to be a constant vector with either constant integer or undef values."

You can either refer to the 2.4 version of the language reference, or update to LLVM trunk.