ARM assembly parsing needs to be paranoid about negative immediates.

Make sure to treat immediates as unsigned when doing relative comparisons.

rdar://11153621

llvm-svn: 153753

2 files changed, 7 insertions, 4 deletions

diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index e0022064ba0..bfac79495c0 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -6835,7 +6835,7 @@ processInstruction(MCInst &Inst,
     // explicitly specified. From the ARM ARM: "Encoding T1 is preferred
     // to encoding T2 if <Rd> is specified and encoding T2 is preferred
     // to encoding T1 if <Rd> is omitted."
-    if (Inst.getOperand(3).getImm() < 8 && Operands.size() == 6) {
+    if ((unsigned)Inst.getOperand(3).getImm() < 8 && Operands.size() == 6) {
       Inst.setOpcode(ARM::tADDi3);
       return true;
     }
@@ -6845,7 +6845,7 @@ processInstruction(MCInst &Inst,
     // explicitly specified. From the ARM ARM: "Encoding T1 is preferred
     // to encoding T2 if <Rd> is specified and encoding T2 is preferred
     // to encoding T1 if <Rd> is omitted."
-    if (Inst.getOperand(3).getImm() < 8 && Operands.size() == 6) {
+    if ((unsigned)Inst.getOperand(3).getImm() < 8 && Operands.size() == 6) {
       Inst.setOpcode(ARM::tSUBi3);
       return true;
     }
@@ -6966,7 +6966,7 @@ processInstruction(MCInst &Inst,
     // If we can use the 16-bit encoding and the user didn't explicitly
     // request the 32-bit variant, transform it here.
     if (isARMLowRegister(Inst.getOperand(0).getReg()) &&
-        Inst.getOperand(1).getImm() <= 255 &&
+        (unsigned)Inst.getOperand(1).getImm() <= 255 &&
         ((!inITBlock() && Inst.getOperand(2).getImm() == ARMCC::AL &&
          Inst.getOperand(4).getReg() == ARM::CPSR) ||
         (inITBlock() && Inst.getOperand(4).getReg() == 0)) &&
diff --git a/llvm/test/MC/ARM/basic-thumb2-instructions.s b/llvm/test/MC/ARM/basic-thumb2-instructions.s
index ce97ca666fe..0cbaae4a54d 100644
--- a/llvm/test/MC/ARM/basic-thumb2-instructions.s
+++ b/llvm/test/MC/ARM/basic-thumb2-instructions.s
@@ -1130,6 +1130,8 @@ _func:
         moveq r1, #12
         movne.w r1, #12
         mov.w r6, #450
+        it lo
+        movlo r1, #-1
 
         @ alias for mvn
 	mov r3, #-3
@@ -1149,7 +1151,8 @@ _func:
 @ CHECK: moveq	r1, #12                 @ encoding: [0x0c,0x21]
 @ CHECK: movne.w r1, #12                @ encoding: [0x4f,0xf0,0x0c,0x01]
 @ CHECK: mov.w	r6, #450                @ encoding: [0x4f,0xf4,0xe1,0x76]
-
+@ CHECK: it	lo                      @ encoding: [0x38,0xbf]
+@ CHECK: movlo.w	r1, #-1         @ encoding: [0x4f,0xf0,0xff,0x31]
 @ CHECK: mvn	r3, #2                  @ encoding: [0x6f,0xf0,0x02,0x03]
 
 @------------------------------------------------------------------------------