ARM: fix fast-isel assertion failure

Missing braces on if meant we inserted both ARM and Thumb load for a litpool
entry. This didn't end well.

rdar://problem/15959157

llvm-svn: 200752

llvm/lib/Target/ARM/ARMFastISel.cpp

@@ -653,13 +653,14 @@ unsigned ARMFastISel::ARMMaterializeInt(const Constant *C, MVT VT) {
     AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                             TII.get(ARM::t2LDRpci), DestReg)
                     .addConstantPoolIndex(Idx));
-  else
+  else {
     // The extra immediate is for addrmode2.
     DestReg = constrainOperandRegClass(TII.get(ARM::LDRcp), DestReg, 0);
     AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
                             TII.get(ARM::LDRcp), DestReg)
                     .addConstantPoolIndex(Idx)
                     .addImm(0));
+  }
 
   return DestReg;
 }

llvm/test/CodeGen/ARM/fastisel-thumb-litpool.ll

@@ -0,0 +1,11 @@
+; RUN: llc -mtriple=thumbv7-apple-ios -O0 -o - %s | FileCheck %s
+
+; We used to accidentally create both an ARM and a Thumb ldr here. It led to an
+; assertion failure at the time, but could go all the way through to emission,
+; hence the CHECK-NOT.
+
+define i32 @test_thumb_ldrlit() minsize {
+; CHECK: ldr r0, LCPI0_0
+; CHECK-NOT: ldr
+  ret i32 12345678
+}