When a block ends in an indirect branch, add its successors to the machine basic block.

The CFG of the machine function needs to know that the targets of the indirect
branch are successors to the indirect branch.
<rdar://problem/12529625>

llvm-svn: 166448

2 files changed, 51 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMFastISel.cpp b/llvm/lib/Target/ARM/ARMFastISel.cpp
index 92248f53178..89b85d09b72 100644
--- a/llvm/lib/Target/ARM/ARMFastISel.cpp
+++ b/llvm/lib/Target/ARM/ARMFastISel.cpp
@@ -1388,6 +1388,11 @@ bool ARMFastISel::SelectIndirectBr(const Instruction *I) {
   unsigned Opc = isThumb2 ? ARM::tBRIND : ARM::BX;
   AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(Opc))
                   .addReg(AddrReg));
+
+  const IndirectBrInst *IB = cast<IndirectBrInst>(I);
+  for (unsigned i = 0, e = IB->getNumSuccessors(); i != e; ++i)
+    FuncInfo.MBB->addSuccessor(FuncInfo.MBBMap[IB->getSuccessor(i)]);
+
   return true;
 }
 
diff --git a/llvm/test/CodeGen/ARM/indirectbr-2.ll b/llvm/test/CodeGen/ARM/indirectbr-2.ll
new file mode 100644
index 00000000000..084f520a8ee
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/indirectbr-2.ll
@@ -0,0 +1,46 @@
+; RUN: llc < %s -O0 -relocation-model=pic -mtriple=thumbv7-apple-ios | FileCheck %s
+; <rdar://problem/12529625>
+
+@foo = global i32 34879, align 4
+@DWJumpTable2808 = global [2 x i32] [i32 sub (i32 ptrtoint (i8* blockaddress(@func, %14) to i32), i32 ptrtoint (i8* blockaddress(@func, %4) to i32)), i32 sub (i32 ptrtoint (i8* blockaddress(@func, %13) to i32), i32 ptrtoint (i8* blockaddress(@func, %4) to i32))]
+@0 = internal constant [45 x i8] c"func XXXXXXXXXXX :: bb xxxxxxxxxxxxxxxxxxxx\0A\00"
+
+; The indirect branch has the two destinations as successors. The lone PHI
+; statement shouldn't be implicitly defined.
+
+; CHECK:      func:
+; CHECK:      Ltmp1:    @ Block address taken
+; CHECK-NOT:            @ implicit-def: R0
+; CHECK:                @ 4-byte Reload
+
+define i32 @func() nounwind ssp {
+  %1 = alloca i32, align 4
+  %2 = load i32* @foo, align 4
+  %3 = icmp eq i32 %2, 34879
+  br label %4
+
+; <label>:4                                       ; preds = %0
+  %5 = zext i1 %3 to i32
+  %6 = mul i32 %5, 287
+  %7 = add i32 %6, 2
+  %8 = getelementptr [2 x i32]* @DWJumpTable2808, i32 0, i32 %5
+  %9 = load i32* %8
+  %10 = add i32 %9, ptrtoint (i8* blockaddress(@func, %4) to i32)
+  %11 = inttoptr i32 %10 to i8*
+  %12 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([45 x i8]* @0, i32 0, i32 0))
+  indirectbr i8* %11, [label %13, label %14]
+
+; <label>:13                                      ; preds = %4
+  %tmp14 = phi i32 [ %7, %4 ]
+  store i32 23958, i32* @foo, align 4
+  %tmp15 = load i32* %1, align 4
+  %tmp16 = icmp eq i32 %tmp15, 0
+  %tmp17 = zext i1 %tmp16 to i32
+  %tmp21 = add i32 %tmp17, %tmp14
+  ret i32 %tmp21
+
+; <label>:14                                      ; preds = %4
+  ret i32 42
+}
+
+declare i32 @printf(i8*, ...)