From a5378ebe7890aa9a4974f2872aa6632f1b7f2400 Mon Sep 17 00:00:00 2001
From: Jim Grosbach <grosbach@apple.com>
Date: Wed, 11 Apr 2012 00:15:16 +0000
Subject: [PATCH] ARM add missing Thumb1 two-operand aliases for
 shift-by-immediate.

rdar://11222742

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154457 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMInstrThumb.td           |  8 ++++++
 lib/Target/ARM/AsmParser/ARMAsmParser.cpp | 31 +++++++++++++++++++++++
 test/MC/ARM/basic-thumb-instructions.s    | 18 +++++++++++++
 3 files changed, 57 insertions(+)

diff --git a/lib/Target/ARM/ARMInstrThumb.td b/lib/Target/ARM/ARMInstrThumb.td
index b9ef6925b51..6335229d3c2 100644
--- a/lib/Target/ARM/ARMInstrThumb.td
+++ b/lib/Target/ARM/ARMInstrThumb.td
@@ -1407,3 +1407,11 @@ def : tInstAlias<"cps$imod", (tCPS imod_op:$imod, 0)>;
 def : tInstAlias<"neg${s}${p} $Rd, $Rm",
                  (tRSB tGPR:$Rd, s_cc_out:$s, tGPR:$Rm, pred:$p)>;
 
+
+// Implied destination operand forms for shifts.
+def : tInstAlias<"lsl${s}${p} $Rdm, $imm",
+             (tLSLri tGPR:$Rdm, cc_out:$s, tGPR:$Rdm, imm0_31:$imm, pred:$p)>;
+def : tInstAlias<"lsr${s}${p} $Rdm, $imm",
+             (tLSRri tGPR:$Rdm, cc_out:$s, tGPR:$Rdm, imm_sr:$imm, pred:$p)>;
+def : tInstAlias<"asr${s}${p} $Rdm, $imm",
+             (tASRri tGPR:$Rdm, cc_out:$s, tGPR:$Rdm, imm_sr:$imm, pred:$p)>;
diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 8fa7378ffff..e55a7dad45d 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -6650,6 +6650,37 @@ processInstruction(MCInst &Inst,
     return true;
   }
 
+  // Handle encoding choice for the shift-immediate instructions.
+  case ARM::t2LSLri:
+  case ARM::t2LSRri:
+  case ARM::t2ASRri: {
+    if (isARMLowRegister(Inst.getOperand(0).getReg()) &&
+        Inst.getOperand(0).getReg() == Inst.getOperand(1).getReg() &&
+        Inst.getOperand(5).getReg() == (inITBlock() ? 0 : ARM::CPSR) &&
+        !(static_cast<ARMOperand*>(Operands[3])->isToken() &&
+         static_cast<ARMOperand*>(Operands[3])->getToken() == ".w")) {
+      unsigned NewOpc;
+      switch (Inst.getOpcode()) {
+      default: llvm_unreachable("unexpected opcode");
+      case ARM::t2LSLri: NewOpc = ARM::tLSLri; break;
+      case ARM::t2LSRri: NewOpc = ARM::tLSRri; break;
+      case ARM::t2ASRri: NewOpc = ARM::tASRri; break;
+      }
+      // The Thumb1 operands aren't in the same order. Awesome, eh?
+      MCInst TmpInst;
+      TmpInst.setOpcode(NewOpc);
+      TmpInst.addOperand(Inst.getOperand(0));
+      TmpInst.addOperand(Inst.getOperand(5));
+      TmpInst.addOperand(Inst.getOperand(1));
+      TmpInst.addOperand(Inst.getOperand(2));
+      TmpInst.addOperand(Inst.getOperand(3));
+      TmpInst.addOperand(Inst.getOperand(4));
+      Inst = TmpInst;
+      return true;
+    }
+    return false;
+  }
+
   // Handle the Thumb2 mode MOV complex aliases.
   case ARM::t2MOVsr:
   case ARM::t2MOVSsr: {
diff --git a/test/MC/ARM/basic-thumb-instructions.s b/test/MC/ARM/basic-thumb-instructions.s
index 0a083d07228..bc2605c16ec 100644
--- a/test/MC/ARM/basic-thumb-instructions.s
+++ b/test/MC/ARM/basic-thumb-instructions.s
@@ -97,10 +97,16 @@ _func:
         asrs r2, r3, #32
         asrs r2, r3, #5
         asrs r2, r3, #1
+        asrs r5, #21
+        asrs r5, r5, #21
+        asrs r3, r5, #21
 
 @ CHECK: asrs	r2, r3, #32             @ encoding: [0x1a,0x10]
 @ CHECK: asrs	r2, r3, #5              @ encoding: [0x5a,0x11]
 @ CHECK: asrs	r2, r3, #1              @ encoding: [0x5a,0x10]
+@ CHECK: asrs	r5, r5, #21             @ encoding: [0x6d,0x15]
+@ CHECK: asrs	r5, r5, #21             @ encoding: [0x6d,0x15]
+@ CHECK: asrs	r3, r5, #21             @ encoding: [0x6b,0x15]
 
 
 @------------------------------------------------------------------------------
@@ -319,9 +325,15 @@ _func:
 @------------------------------------------------------------------------------
         lsls r4, r5, #0
         lsls r4, r5, #4
+        lsls r3, #12
+        lsls r3, r3, #12
+        lsls r1, r3, #12
 
 @ CHECK: lsls	r4, r5, #0              @ encoding: [0x2c,0x00]
 @ CHECK: lsls	r4, r5, #4              @ encoding: [0x2c,0x01]
+@ CHECK: lsls	r3, r3, #12             @ encoding: [0x1b,0x03]
+@ CHECK: lsls	r3, r3, #12             @ encoding: [0x1b,0x03]
+@ CHECK: lsls	r1, r3, #12             @ encoding: [0x19,0x03]
 
 
 @------------------------------------------------------------------------------
@@ -337,9 +349,15 @@ _func:
 @------------------------------------------------------------------------------
         lsrs r1, r3, #1
         lsrs r1, r3, #32
+        lsrs r4, #20
+        lsrs r4, r4, #20
+        lsrs r2, r4, #20
 
 @ CHECK: lsrs	r1, r3, #1              @ encoding: [0x59,0x08]
 @ CHECK: lsrs	r1, r3, #32             @ encoding: [0x19,0x08]
+@ CHECK: lsrs	r4, r4, #20             @ encoding: [0x24,0x0d]
+@ CHECK: lsrs	r4, r4, #20             @ encoding: [0x24,0x0d]
+@ CHECK: lsrs	r2, r4, #20             @ encoding: [0x22,0x0d]
 
 
 @------------------------------------------------------------------------------