Thumb2 ldr pc-relative encoding fixes.

We were parsing label references to the i12 encoding, which isn't right.
They need to go to the pci variant instead.

More of rdar://10348687

llvm-svn: 143068

2 files changed, 16 insertions, 7 deletions

diff --git a/llvm/lib/Target/ARM/ARMInstrThumb2.td b/llvm/lib/Target/ARM/ARMInstrThumb2.td
index 3facc64b494..cc137a8982d 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb2.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb2.td
@@ -1460,7 +1460,7 @@ def t2STRD_POST : T2Ii8s4post<0, 1, 0, (outs GPR:$wb),
                  "$addr.base = $wb", []>;
 
 // T2Ipl (Preload Data/Instruction) signals the memory system of possible future
-// data/instruction access.  These are for disassembly only.
+// data/instruction access.
 // instr_write is inverted for Thumb mode: (prefetch 3) -> (preload 0),
 // (prefetch 1) -> (preload 2),  (prefetch 2) -> (preload 1).
 multiclass T2Ipl<bits<1> write, bits<1> instr, string opc> {
@@ -1518,6 +1518,10 @@ multiclass T2Ipl<bits<1> write, bits<1> instr, string opc> {
 
     let DecoderMethod = "DecodeT2LoadShift";
   }
+  // FIXME: We should have a separate 'pci' variant here. As-is we represent
+  // it via the i12 variant, which it's related to, but that means we can
+  // represent negative immediates, which aren't legal for anything except
+  // the 'pci' case (Rn == 15).
 }
 
 defm t2PLD  : T2Ipl<0, 0, "pld">,  Requires<[IsThumb2]>;
@@ -3906,6 +3910,17 @@ def : t2InstAlias<"ldrsb${p} $Rt, $addr",
 def : t2InstAlias<"ldrsh${p} $Rt, $addr",
                   (t2LDRSHs rGPR:$Rt, t2addrmode_so_reg:$addr, pred:$p)>;
 
+def : t2InstAlias<"ldr${p} $Rt, $addr",
+                  (t2LDRpci GPR:$Rt, t2ldrlabel:$addr, pred:$p)>;
+def : t2InstAlias<"ldrb${p} $Rt, $addr",
+                  (t2LDRBpci rGPR:$Rt, t2ldrlabel:$addr, pred:$p)>;
+def : t2InstAlias<"ldrh${p} $Rt, $addr",
+                  (t2LDRHpci rGPR:$Rt, t2ldrlabel:$addr, pred:$p)>;
+def : t2InstAlias<"ldrsb${p} $Rt, $addr",
+                  (t2LDRSBpci rGPR:$Rt, t2ldrlabel:$addr, pred:$p)>;
+def : t2InstAlias<"ldrsh${p} $Rt, $addr",
+                  (t2LDRSHpci rGPR:$Rt, t2ldrlabel:$addr, pred:$p)>;
+
 // Alias for MVN without the ".w" optional width specifier.
 def : t2InstAlias<"mvn${s}${p} $Rd, $Rm",
            (t2MVNr rGPR:$Rd, rGPR:$Rm, pred:$p, cc_out:$s)>;
diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 99f619cb119..8803b687782 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -865,12 +865,6 @@ public:
     return Val > -256 && Val < 0;
   }
   bool isMemUImm12Offset() const {
-    // If we have an immediate that's not a constant, treat it as a label
-    // reference needing a fixup. If it is a constant, it's something else
-    // and we reject it.
-    if (Kind == k_Immediate && !isa<MCConstantExpr>(getImm()))
-      return true;
-
     if (!isMemory() || Memory.OffsetRegNum != 0 || Memory.Alignment != 0)
       return false;
     // Immediate offset in range [0, 4095].