Implement jump threading of 'indirectbr' by keeping track of whether we're looking for ConstantInt*s or BlockAddress*s.

llvm-svn: 121066

1 files changed, 61 insertions, 0 deletions

diff --git a/llvm/test/Transforms/JumpThreading/indirectbr.ll b/llvm/test/Transforms/JumpThreading/indirectbr.ll
new file mode 100644
index 00000000000..6c5321d3194
--- /dev/null
+++ b/llvm/test/Transforms/JumpThreading/indirectbr.ll
@@ -0,0 +1,61 @@
+; RUN: opt -S < %s -jump-threading | FileCheck %s
+
+; Keep block addresses alive.
+@addresses = constant [4 x i8*] [
+  i8* blockaddress(@test1, %L1), i8* blockaddress(@test1, %L2),
+  i8* blockaddress(@test2, %L1), i8* blockaddress(@test2, %L2)
+]
+
+declare void @bar()
+declare void @baz()
+
+
+
+; Check basic jump threading for indirectbr instructions.
+
+; CHECK: void @test1
+; CHECK: br i1 %tobool, label %L1, label %indirectgoto
+; CHECK-NOT: if.else:
+; CHECK: L1:
+; CHECK: indirectbr i8* %address, [label %L1, label %L2]
+define void @test1(i32 %i, i8* %address) nounwind {
+entry:
+  %rem = srem i32 %i, 2
+  %tobool = icmp ne i32 %rem, 0
+  br i1 %tobool, label %indirectgoto, label %if.else
+
+if.else:                                          ; preds = %entry
+  br label %indirectgoto
+
+L1:                                               ; preds = %indirectgoto
+  call void @bar()
+  ret void
+
+L2:                                               ; preds = %indirectgoto
+  call void @baz()
+  ret void
+
+indirectgoto:                                     ; preds = %if.else, %entry
+  %indirect.goto.dest = phi i8* [ %address, %if.else ], [ blockaddress(@test1, %L1), %entry ]
+  indirectbr i8* %indirect.goto.dest, [label %L1, label %L2]
+}
+
+
+; Check constant folding of indirectbr
+
+; CHECK: void @test2
+; CHECK-NEXT: :
+; CHECK-NEXT: call void @bar
+; CHECK-NEXT: ret void
+define void @test2() nounwind {
+entry:
+  indirectbr i8* blockaddress(@test2, %L1), [label %L1, label %L2]
+
+L1:                                               ; preds = %indirectgoto
+  call void @bar()
+  ret void
+
+L2:                                               ; preds = %indirectgoto
+  call void @baz()
+  ret void
+}