[PowerPC] Ensure displacements for DQ-Form instructions are multiples of 16

As outlined in the PR, we didn't ensure that displacements for DQ-Form
instructions are multiples of 16. Since the instruction encoding encodes
a quad-word displacement, a sub-16 byte displacement is meaningless and
ends up being encoded incorrectly.

Fixes https://bugs.llvm.org/show_bug.cgi?id=33671.

Differential Revision: https://reviews.llvm.org/D35007

llvm-svn: 307934

1 files changed, 9 insertions, 9 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 0e069ec1665..b3a3c73f6df 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -2130,12 +2130,12 @@ static void fixupFuncForFI(SelectionDAG &DAG, int FrameIdx, EVT VT) {
 
 /// Returns true if the address N can be represented by a base register plus
 /// a signed 16-bit displacement [r+imm], and if it is not better
-/// represented as reg+reg.  If Aligned is true, only accept displacements
-/// suitable for STD and friends, i.e. multiples of 4.
+/// represented as reg+reg.  If \p Alignment is non-zero, only accept
+/// displacements that are multiples of that value.
 bool PPCTargetLowering::SelectAddressRegImm(SDValue N, SDValue &Disp,
                                             SDValue &Base,
                                             SelectionDAG &DAG,
-                                            bool Aligned) const {
+                                            unsigned Alignment) const {
   // FIXME dl should come from parent load or store, not from address
   SDLoc dl(N);
   // If this can be more profitably realized as r+r, fail.
@@ -2145,7 +2145,7 @@ bool PPCTargetLowering::SelectAddressRegImm(SDValue N, SDValue &Disp,
   if (N.getOpcode() == ISD::ADD) {
     int16_t imm = 0;
     if (isIntS16Immediate(N.getOperand(1), imm) &&
-        (!Aligned || (imm & 3) == 0)) {
+        (!Alignment || (imm % Alignment) == 0)) {
       Disp = DAG.getTargetConstant(imm, dl, N.getValueType());
       if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(N.getOperand(0))) {
         Base = DAG.getTargetFrameIndex(FI->getIndex(), N.getValueType());
@@ -2169,7 +2169,7 @@ bool PPCTargetLowering::SelectAddressRegImm(SDValue N, SDValue &Disp,
   } else if (N.getOpcode() == ISD::OR) {
     int16_t imm = 0;
     if (isIntS16Immediate(N.getOperand(1), imm) &&
-        (!Aligned || (imm & 3) == 0)) {
+        (!Alignment || (imm % Alignment) == 0)) {
       // If this is an or of disjoint bitfields, we can codegen this as an add
       // (for better address arithmetic) if the LHS and RHS of the OR are
       // provably disjoint.
@@ -2196,7 +2196,7 @@ bool PPCTargetLowering::SelectAddressRegImm(SDValue N, SDValue &Disp,
     // If this address fits entirely in a 16-bit sext immediate field, codegen
     // this as "d, 0"
     int16_t Imm;
-    if (isIntS16Immediate(CN, Imm) && (!Aligned || (Imm & 3) == 0)) {
+    if (isIntS16Immediate(CN, Imm) && (!Alignment || (Imm % Alignment) == 0)) {
       Disp = DAG.getTargetConstant(Imm, dl, CN->getValueType(0));
       Base = DAG.getRegister(Subtarget.isPPC64() ? PPC::ZERO8 : PPC::ZERO,
                              CN->getValueType(0));
@@ -2206,7 +2206,7 @@ bool PPCTargetLowering::SelectAddressRegImm(SDValue N, SDValue &Disp,
     // Handle 32-bit sext immediates with LIS + addr mode.
     if ((CN->getValueType(0) == MVT::i32 ||
          (int64_t)CN->getZExtValue() == (int)CN->getZExtValue()) &&
-        (!Aligned || (CN->getZExtValue() & 3) == 0)) {
+        (!Alignment || (CN->getZExtValue() % Alignment) == 0)) {
       int Addr = (int)CN->getZExtValue();
 
       // Otherwise, break this down into an LIS + disp.
@@ -2321,14 +2321,14 @@ bool PPCTargetLowering::getPreIndexedAddressParts(SDNode *N, SDValue &Base,
 
   // LDU/STU can only handle immediates that are a multiple of 4.
   if (VT != MVT::i64) {
-    if (!SelectAddressRegImm(Ptr, Offset, Base, DAG, false))
+    if (!SelectAddressRegImm(Ptr, Offset, Base, DAG, 0))
       return false;
   } else {
     // LDU/STU need an address with at least 4-byte alignment.
     if (Alignment < 4)
       return false;
 
-    if (!SelectAddressRegImm(Ptr, Offset, Base, DAG, true))
+    if (!SelectAddressRegImm(Ptr, Offset, Base, DAG, 4))
       return false;
   }