Add "sub immediate" instruction to the ARM integrated assembler.

src/IceInstARM32.cpp

Index: src/IceInstARM32.cpp
diff --git a/src/IceInstARM32.cpp b/src/IceInstARM32.cpp
index b637472ea60a8b577a704e51a5627cc88839e2f0..c4d9ebc10a72bb751f177c6bde3775d9d943f48b 100644
--- a/src/IceInstARM32.cpp
+++ b/src/IceInstARM32.cpp
@@ -330,6 +330,12 @@ void InstARM32ThreeAddrGPR<InstARM32::Add>::emitIAS(const Cfg *Func) const {
   Asm->add(getDest(), getSrc(0), getSrc(1), SetFlags, getPredicate());
 }
 
+template <>
+void InstARM32ThreeAddrGPR<InstARM32::Sub>::emitIAS(const Cfg *Func) const {
+  ARM32::AssemblerARM32 *Asm = Func->getAssembler<ARM32::AssemblerARM32>();
+  Asm->sub(getDest(), getSrc(0), getSrc(1), SetFlags, getPredicate());
+}
+
 InstARM32Call::InstARM32Call(Cfg *Func, Variable *Dest, Operand *CallTarget)
     : InstARM32(Func, InstARM32::Call, 1, Dest) {
   HasSideEffects = true;