Until we have a "ALIGN" pseudo instruction, have asm printer emitted a .align

to ensure the instruction that follows a TBB (when the number of table entries
is odd) is 2-byte aligned.
Patch by Sandeep Patel.

llvm-svn: 77705

2 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp b/llvm/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
index a80a88e1d35..5feafb42977 100644
--- a/llvm/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
+++ b/llvm/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
@@ -988,6 +988,13 @@ void ARMAsmPrinter::printJT2BlockOperand(const MachineInstr *MI, int OpNum) {
     if (i != e-1)
       O << '\n';
   }
+
+  // Make sure the instruction that follows TBB is 2-byte aligned.
+  // FIXME: Constant island pass should insert an "ALIGN" instruction instead.
+  if (ByteOffset && (JTBBs.size() & 1)) {
+    O << '\n';
+    EmitAlignment(1);
+  }
 }
 
 void ARMAsmPrinter::printTBAddrMode(const MachineInstr *MI, int OpNum) {
diff --git a/llvm/test/CodeGen/Thumb2/thumb2-tbb.ll b/llvm/test/CodeGen/Thumb2/thumb2-tbb.ll
index c0347c78479..94372334d6e 100644
--- a/llvm/test/CodeGen/Thumb2/thumb2-tbb.ll
+++ b/llvm/test/CodeGen/Thumb2/thumb2-tbb.ll
@@ -5,6 +5,7 @@ define void @bar(i32 %n.u) {
 entry:
 ; CHECK: bar:
 ; CHECK: tbb
+; CHECK: .align 1
 
     switch i32 %n.u, label %bb12 [i32 1, label %bb i32 2, label %bb6 i32 4, label %bb7 i32 5, label %bb8 i32 6, label %bb10 i32 7, label %bb1 i32 8, label %bb3 i32 9, label %bb4 i32 10, label %bb9 i32 11, label %bb2 i32 12, label %bb5 i32 13, label %bb11 ]
 bb: