ARM thumb2 parsing of "rsb rd, rn, #0".

rdar://10549741

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146515 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 35251f02b8ef147995fd0c48f13c777b06dffa6a..f6827809cd711364b30bfdec9dabf59bb5b22554 100644 (file)
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -4727,12 +4727,18 @@ bool ARMAsmParser::ParseInstruction(StringRef Name, SMLoc NameLoc,
     }
   }
   // Similarly, the Thumb1 "RSB" instruction has a literal "#0" on the
-  // end. Convert it to a token here.
+  // end. Convert it to a token here. Take care not to convert those
+  // that should hit the Thumb2 encoding.
   if (Mnemonic == "rsb" && isThumb() && Operands.size() == 6 &&
+      static_cast<ARMOperand*>(Operands[3])->isReg() &&
+      static_cast<ARMOperand*>(Operands[4])->isReg() &&
       static_cast<ARMOperand*>(Operands[5])->isImm()) {
     ARMOperand *Op = static_cast<ARMOperand*>(Operands[5]);
     const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(Op->getImm());
-    if (CE && CE->getValue() == 0) {
+    if (CE && CE->getValue() == 0 &&
+        (isThumbOne() ||
+         (isARMLowRegister(static_cast<ARMOperand*>(Operands[3])->getReg()) &&
+          isARMLowRegister(static_cast<ARMOperand*>(Operands[4])->getReg())))) {
       Operands.erase(Operands.begin() + 5);
       Operands.push_back(ARMOperand::CreateToken("#0", Op->getStartLoc()));
       delete Op;

diff --git a/test/MC/ARM/basic-thumb2-instructions.s b/test/MC/ARM/basic-thumb2-instructions.s
index c3500bb4916c9c7dcb5c8ae8a059cf184232871c..68ca277db39e88232151e8086bebcf7d1f171ce8 100644 (file)
--- a/test/MC/ARM/basic-thumb2-instructions.s
+++ b/test/MC/ARM/basic-thumb2-instructions.s
@@ -1668,11 +1668,15 @@ _func:
         rsbs r3, r12, #0xf
         rsb r1, #0xff
         rsb r1, r1, #0xff
+        rsb r11, r11, #0
+        rsb r9, #0
 
 @ CHECK: rsb.w r2, r5, #1044480        @ encoding: [0xc5,0xf5,0x7f,0x22]
 @ CHECK: rsbs.w        r3, r12, #15            @ encoding: [0xdc,0xf1,0x0f,0x03]
 @ CHECK: rsb.w r1, r1, #255            @ encoding: [0xc1,0xf1,0xff,0x01]
 @ CHECK: rsb.w r1, r1, #255            @ encoding: [0xc1,0xf1,0xff,0x01]
+@ CHECK: rsb.w r11, r11, #0            @ encoding: [0xcb,0xf1,0x00,0x0b]
+@ CHECK: rsb.w r9, r9, #0              @ encoding: [0xc9,0xf1,0x00,0x09]
 
 
 @------------------------------------------------------------------------------