ARM: fix literal load with positive offset encoding

When using a positive offset, literal loads where encoded
as if it was negative, because:
- The sign bit was not assigned to an operand
- The addrmode_imm12 operand was not encoding the sign bit correctly

This patch also makes the assembler look at the .w/.n specifier for
loads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184182 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 27 insertions, 6 deletions

diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index 8e19d32aca..2693f32904 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -1024,16 +1024,16 @@ multiclass T2I_ld<bit signed, bits<2> opcod, string opc,
   def pci : T2Ipc <(outs target:$Rt), (ins t2ldrlabel:$addr), iii,
                    opc, ".w\t$Rt, $addr",
                    [(set target:$Rt, (opnode (ARMWrapper tconstpool:$addr)))]> {
+    bits<4> Rt;
+    bits<13> addr;
     let isReMaterializable = 1;
     let Inst{31-27} = 0b11111;
     let Inst{26-25} = 0b00;
     let Inst{24} = signed;
-    let Inst{23} = ?; // add = (U == '1')
+    let Inst{23} = addr{12}; // add = (U == '1')
     let Inst{22-21} = opcod;
     let Inst{20} = 1; // load
     let Inst{19-16} = 0b1111; // Rn
-    bits<4> Rt;
-    bits<12> addr;
     let Inst{15-12} = Rt{3-0};
     let Inst{11-0}  = addr{11-0};
 
diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index e315d16574..170d434744 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -5862,7 +5862,9 @@ processInstruction(MCInst &Inst,
   case ARM::t2LDRpcrel:
     // Select the narrow version if the immediate will fit.
     if (Inst.getOperand(1).getImm() > 0 &&
-        Inst.getOperand(1).getImm() <= 0xff)
+        Inst.getOperand(1).getImm() <= 0xff &&
+        !(static_cast<ARMOperand*>(Operands[2])->isToken() &&
+         static_cast<ARMOperand*>(Operands[2])->getToken() == ".w"))
       Inst.setOpcode(ARM::tLDRpci);
     else
       Inst.setOpcode(ARM::t2LDRpci);
diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp b/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
index f324bc2e37..8631d81ea0 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
@@ -743,10 +743,10 @@ getAddrModeImm12OpValue(const MCInst &MI, unsigned OpIdx,
   if (!MO.isReg()) {
     Reg = CTX.getRegisterInfo()->getEncodingValue(ARM::PC);   // Rn is PC.
     Imm12 = 0;
-    isAdd = false ; // 'U' bit is set as part of the fixup.
 
     if (MO.isExpr()) {
       const MCExpr *Expr = MO.getExpr();
+      isAdd = false ; // 'U' bit is set as part of the fixup.
 
       MCFixupKind Kind;
       if (isThumb2())
diff --git a/test/MC/ARM/basic-thumb2-instructions.s b/test/MC/ARM/basic-thumb2-instructions.s
index 978ec8298d..9eb9244faa 100644
--- a/test/MC/ARM/basic-thumb2-instructions.s
+++ b/test/MC/ARM/basic-thumb2-instructions.s
@@ -3515,12 +3515,31 @@ _func:
 @------------------------------------------------------------------------------
 @ Alternate syntax for LDR*(literal) encodings
 @------------------------------------------------------------------------------
+        ldrb r11, [pc, #22]
+        ldrh r11, [pc, #22]
+        ldrsb r11, [pc, #22]
+        ldrsh r11, [pc, #22]
+        ldr.w r11, [pc, #22]
+        ldrb.w r11, [pc, #22]
+        ldrh.w r11, [pc, #22]
+        ldrsb.w r11, [pc, #22]
+        ldrsh.w r11, [pc, #22]
+
+@ CHECK: ldrb.w r11, [pc, #22]        @ encoding: [0x9f,0xf8,0x16,0xb0]
+@ CHECK: ldrh.w r11, [pc, #22]        @ encoding: [0xbf,0xf8,0x16,0xb0]
+@ CHECK: ldrsb.w r11, [pc, #22]       @ encoding: [0x9f,0xf9,0x16,0xb0]
+@ CHECK: ldrsh.w r11, [pc, #22]       @ encoding: [0xbf,0xf9,0x16,0xb0]
+@ CHECK: ldr.w r11, [pc, #22]         @ encoding: [0xdf,0xf8,0x16,0xb0]
+@ CHECK: ldrb.w r11, [pc, #22]        @ encoding: [0x9f,0xf8,0x16,0xb0]
+@ CHECK: ldrh.w r11, [pc, #22]        @ encoding: [0xbf,0xf8,0x16,0xb0]
+@ CHECK: ldrsb.w r11, [pc, #22]       @ encoding: [0x9f,0xf9,0x16,0xb0]
+@ CHECK: ldrsh.w r11, [pc, #22]       @ encoding: [0xbf,0xf9,0x16,0xb0]
+
         ldr r11, [pc, #-22]
         ldrb r11, [pc, #-22]
         ldrh r11, [pc, #-22]
         ldrsb r11, [pc, #-22]
         ldrsh r11, [pc, #-22]
-
         ldr.w r11, [pc, #-22]
         ldrb.w r11, [pc, #-22]
         ldrh.w r11, [pc, #-22]