[X86] Reverse the operand order of the implementation of the kunpack builtins.
The second operand needs to be in the lower bits of the concatenation. This matches llvm 5.0, gcc, and icc behavior.
Fixes PR36360.
llvm-svn: 324954
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 8a48b4e..49dfc60 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -8846,7 +8846,8 @@
RHS = Builder.CreateShuffleVector(RHS, RHS,
makeArrayRef(Indices, NumElts / 2));
// Concat the vectors.
- Value *Res = Builder.CreateShuffleVector(LHS, RHS,
+ // NOTE: Operands are swapped to match the intrinsic definition.
+ Value *Res = Builder.CreateShuffleVector(RHS, LHS,
makeArrayRef(Indices, NumElts));
return Builder.CreateBitCast(Res, Ops[0]->getType());
}