From c537f3be0c4ff7030afcdcd9f55133ce68eef773 Mon Sep 17 00:00:00 2001
From: Owen Anderson <resistor@mac.com>
Date: Mon, 15 Aug 2011 20:51:32 +0000
Subject: [PATCH] Enforce the constraint that Rt must be even on LDRD/STRD
 instructions in ARM mode.  Update tests to reflect this fact. Patch by James
 Molloy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137647 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../ARM/Disassembler/ARMDisassembler.cpp      | 15 +++++
 .../ARM/memory-arm-instructions.txt           | 65 +++++++++----------
 2 files changed, 47 insertions(+), 33 deletions(-)

diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index e7b555a22fe..852c52af8be 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -1094,6 +1094,21 @@ static bool DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
   unsigned P = fieldFromInstruction32(Insn, 24, 1);
 
   bool writeback = (W == 1) | (P == 0);
+
+  // For {LD,ST}RD, Rt must be even, else undefined.
+  switch (Inst.getOpcode()) {
+    case ARM::STRD:
+    case ARM::STRD_PRE:
+    case ARM::STRD_POST:
+    case ARM::LDRD:
+    case ARM::LDRD_PRE:
+    case ARM::LDRD_POST:
+      if (Rt & 0x1) return false;
+      break;
+  default:
+    break;
+  }
+
   if (writeback) { // Writeback
     if (P)
       U |= ARMII::IndexModePre << 9;
diff --git a/test/MC/Disassembler/ARM/memory-arm-instructions.txt b/test/MC/Disassembler/ARM/memory-arm-instructions.txt
index aba0ba412c0..4fa28975bec 100644
--- a/test/MC/Disassembler/ARM/memory-arm-instructions.txt
+++ b/test/MC/Disassembler/ARM/memory-arm-instructions.txt
@@ -104,21 +104,21 @@
 #------------------------------------------------------------------------------
 # LDRD (immediate)
 #------------------------------------------------------------------------------
-# CHECK: ldrd r3, r4, [r5
-# CHECK: ldrd r7, r8, [r2, #15
-# CHECK: ldrd r1, r2, [r9, #32]!
+# CHECK: ldrd r0, r1, [r5]
+# CHECK: ldrd r8, r9, [r2, #15]
+# CHECK: ldrd r2, r3, [r9, #32]!
 # CHECK: ldrd r6, r7, [r1], #8
-# CHECK: ldrd r1, r2, [r8], #0
-# CHECK: ldrd r1, r2, [r8], #0
-# CHECK: ldrd r1, r2, [r8], #-0
+# CHECK: ldrd r2, r3, [r8], #0
+# CHECK: ldrd r2, r3, [r8], #0
+# CHECK: ldrd r2, r3, [r8], #-0
 
-0xd0 0x30 0xc5 0xe1
-0xdf 0x70 0xc2 0xe1
-0xd0 0x12 0xe9 0xe1
+0xd0 0x00 0xc5 0xe1
+0xdf 0x80 0xc2 0xe1
+0xd0 0x22 0xe9 0xe1
 0xd8 0x60 0xc1 0xe0
-0xd0 0x10 0xc8 0xe0
-0xd0 0x10 0xc8 0xe0
-0xd0 0x10 0x48 0xe0
+0xd0 0x20 0xc8 0xe0
+0xd0 0x20 0xc8 0xe0
+0xd0 0x20 0x48 0xe0
 
 
 #------------------------------------------------------------------------------
@@ -128,15 +128,15 @@
 #------------------------------------------------------------------------------
 # LDRD (register)
 #------------------------------------------------------------------------------
-# CHECK: ldrd r3, r4, [r1, r3
+# CHECK: ldrd r4, r5, [r1, r3]
 # CHECK: ldrd r4, r5, [r7, r2]!
-# CHECK: ldrd r1, r2, [r8], r12
-# CHECK: ldrd r1, r2, [r8], -r12
+# CHECK: ldrd r0, r1, [r8], r12
+# CHECK: ldrd r0, r1, [r8], -r12
 
-0xd3 0x30 0x81 0xe1
+0xd3 0x40 0x81 0xe1
 0xd2 0x40 0xa7 0xe1
-0xdc 0x10 0x88 0xe0
-0xdc 0x10 0x08 0xe0
+0xdc 0x00 0x88 0xe0
+0xdc 0x00 0x08 0xe0
 
 
 #------------------------------------------------------------------------------
@@ -388,21 +388,21 @@
 #------------------------------------------------------------------------------
 # STRD (immediate)
 #------------------------------------------------------------------------------
-# CHECK: strd r1, r2, [r4
-# CHECK: strd r2, r3, [r6, #1
-# CHECK: strd r3, r4, [r7, #22]!
+# CHECK: strd r0, r1, [r4]
+# CHECK: strd r2, r3, [r6, #1]
+# CHECK: strd r2, r3, [r7, #22]!
 # CHECK: strd r4, r5, [r8], #7
-# CHECK: strd r5, r6, [sp], #0
+# CHECK: strd r4, r5, [sp], #0
 # CHECK: strd r6, r7, [lr], #0
-# CHECK: strd r7, r8, [r9], #-0
+# CHECK: strd r6, r7, [r9], #-0
 
-0xf0 0x10 0xc4 0xe1
+0xf0 0x00 0xc4 0xe1
 0xf1 0x20 0xc6 0xe1
-0xf6 0x31 0xe7 0xe1
+0xf6 0x21 0xe7 0xe1
 0xf7 0x40 0xc8 0xe0
-0xf0 0x50 0xcd 0xe0
+0xf0 0x40 0xcd 0xe0
 0xf0 0x60 0xce 0xe0
-0xf0 0x70 0x49 0xe0
+0xf0 0x60 0x49 0xe0
 
 
 #------------------------------------------------------------------------------
@@ -412,16 +412,15 @@
 #------------------------------------------------------------------------------
 # STRD (register)
 #------------------------------------------------------------------------------
-# CHECK: strd r8, r9, [r4, r1
-# CHECK: strd r7, r8, [r3, r9]!
+# CHECK: strd r8, r9, [r4, r1]
+# CHECK: strd r6, r7, [r3, r9]!
 # CHECK: strd r6, r7, [r5], r8
-# CHECK: strd r5, r6, [r12], -r10
+# CHECK: strd r4, r5, [r12], -r10
 
 0xf1 0x80 0x84 0xe1
-0xf9 0x70 0xa3 0xe1
+0xf9 0x60 0xa3 0xe1
 0xf8 0x60 0x85 0xe0
-0xfa 0x50 0x0c 0xe0
-
+0xfa 0x40 0x0c 0xe0
 
 #------------------------------------------------------------------------------
 # STRH (immediate)