[mips][msa] Fix corner case for integer constant splats with undef values.

lowerBUILD_VECTOR() was treating integer constant splats as being legal
regardless of whether they had undef values. This caused instruction
selection failures when the undefs were legalized to zero, making the
constant non-splat.

Fixed this by requiring HasAnyUndef to be false for a integer constant
splat to be legal. If it is true, a new node is generated with the undefs
replaced with the necessary values to remain a splat.

llvm-svn: 195455

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/Target/Mips/MipsSEISelLowering.cpp b/llvm/lib/Target/Mips/MipsSEISelLowering.cpp
index c02c235eb7d..0c9cecb7335 100644
--- a/llvm/lib/Target/Mips/MipsSEISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsSEISelLowering.cpp
@@ -2211,8 +2211,9 @@ SDValue MipsSETargetLowering::lowerBUILD_VECTOR(SDValue Op,
 
     // If the value fits into a simm10 then we can use ldi.[bhwd]
     // However, if it isn't an integer type we will have to bitcast from an
-    // integer type first.
-    if (ResTy.isInteger() && SplatValue.isSignedIntN(10))
+    // integer type first. Also, it there are any undefs, we must lower them
+    // to defined values first.
+    if (ResTy.isInteger() && !HasAnyUndefs && SplatValue.isSignedIntN(10))
       return Op;
 
     EVT ViaVecTy;