[PowerPC] PR19796: Also match ISD::TargetConstant in isIntS16Immediate
The SplitIndexingFromLoad changes exposed a latent isel bug in the PowerPC64
backend. We matched an immediate offset with STWX8 even though it only
supports register offset.
The culprit is the complex-pattern predicate, SelectAddrIdx, which decides
that if the offset is not ISD::Constant it must be a register.
Many thanks to Bill Schmidt for testing this.
llvm-svn: 209219
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 04bd435..214c869 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -1137,7 +1137,7 @@
/// sign extension from a 16-bit value. If so, this returns true and the
/// immediate.
static bool isIntS16Immediate(SDNode *N, short &Imm) {
- if (N->getOpcode() != ISD::Constant)
+ if (!isa<ConstantSDNode>(N))
return false;
Imm = (short)cast<ConstantSDNode>(N)->getZExtValue();