Fix PPC unaligned 64-bit loads and stores
PPC64 supports unaligned loads and stores of 64-bit values, but
in order to use the r+i forms, the offset must be a multiple of 4.
Unfortunately, this cannot always be determined by examining the
immediate itself because it might be available only via a TOC entry.
In order to get around this issue, we additionally predicate the
selection of the r+i form on the alignment of the load or store
(forcing it to be at least 4 in order to select the r+i form).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177338 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index a7e9d56..741e25e 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -1183,13 +1183,15 @@
SDValue Ptr;
EVT VT;
+ unsigned Alignment;
if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
Ptr = LD->getBasePtr();
VT = LD->getMemoryVT();
-
+ Alignment = LD->getAlignment();
} else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
Ptr = ST->getBasePtr();
VT = ST->getMemoryVT();
+ Alignment = ST->getAlignment();
} else
return false;
@@ -1208,6 +1210,10 @@
if (!SelectAddressRegImm(Ptr, Offset, Base, DAG))
return false;
} else {
+ // LDU/STU need an address with at least 4-byte alignment.
+ if (Alignment < 4)
+ return false;
+
// reg + imm * 4.
if (!SelectAddressRegImmShift(Ptr, Offset, Base, DAG))
return false;