LDRi12 machine instructions handle negative offset operands normally (simple

integer values), not with the addrmode2 encoding.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117429 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 14 insertions, 4 deletions

diff --git a/lib/Target/ARM/ARMBaseInstrInfo.cpp b/lib/Target/ARM/ARMBaseInstrInfo.cpp
index 7d09fa8b5e..69e10baafb 100644
--- a/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -1419,8 +1419,15 @@ bool llvm::rewriteARMFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
       if ((unsigned)Offset <= Mask * Scale) {
         // Replace the FrameIndex with sp
         MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
-        if (isSub)
-          ImmedOffset |= 1 << NumBits;
+        // FIXME: When addrmode2 goes away, this will simplify (like the
+        // T2 version), as the LDR.i12 versions don't need the encoding
+        // tricks for the offset value.
+        if (isSub) {
+          if (AddrMode == ARMII::AddrMode_i12)
+            ImmedOffset = -ImmedOffset;
+          else
+            ImmedOffset |= 1 << NumBits;
+        }
         ImmOp.ChangeToImmediate(ImmedOffset);
         Offset = 0;
         return true;
diff --git a/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp b/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
index 5df5aa16aa..892558eed3 100644
--- a/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
+++ b/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
@@ -612,8 +612,11 @@ void ARMInstPrinter::printAddrModeImm12Operand(const MCInst *MI, unsigned OpNum,
 
   O << "[" << getRegisterName(MO1.getReg());
 
-  unsigned OffImm = MO2.getImm();
-  if (OffImm)  // Don't print +0.
+  int32_t OffImm = (int32_t)MO2.getImm();
+  // Don't print +0.
+  if (OffImm < 0)
+    O << ", #-" << -OffImm;
+  else if (OffImm > 0)
     O << ", #" << OffImm;
   O << "]";
 }