SelectionDAG: Teach FoldConstantArithmetic how to deal with vectors.
This required disabling a PowerPC optimization that did the following:
input:
x = BUILD_VECTOR <i32 16, i32 16, i32 16, i32 16>
lowered to:
tmp = BUILD_VECTOR <i32 8, i32 8, i32 8, i32 8>
x = ADD tmp, tmp
The add now gets folded immediately and we're back at the BUILD_VECTOR we
started from. I don't see a way to fix this currently so I left it disabled
for now.
Fix some trivially foldable X86 tests too.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174325 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 9a68927..4cd0fc4 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -5032,9 +5032,14 @@
// If this value is in the range [-32,30] and is even, use:
// tmp = VSPLTI[bhw], result = add tmp, tmp
if (SextVal >= -32 && SextVal <= 30 && (SextVal & 1) == 0) {
+ // FIXME: This is currently disabled because the ADD will be folded back
+ // into an invalid BUILD_VECTOR immediately.
+ return SDValue();
+#if 0
SDValue Res = BuildSplatI(SextVal >> 1, SplatSize, MVT::Other, DAG, dl);
Res = DAG.getNode(ISD::ADD, dl, Res.getValueType(), Res, Res);
return DAG.getNode(ISD::BITCAST, dl, Op.getValueType(), Res);
+#endif
}
// If this is 0x8000_0000 x 4, turn into vspltisw + vslw. If it is