Rebased PNaCl localmods in LLVM to 223109

test/Transforms/NaCl/pnacl-sjlj-eh-bug.ll

Index: test/Transforms/NaCl/pnacl-sjlj-eh-bug.ll
diff --git a/test/Transforms/NaCl/pnacl-sjlj-eh-bug.ll b/test/Transforms/NaCl/pnacl-sjlj-eh-bug.ll
new file mode 100644
index 0000000000000000000000000000000000000000..e0796881285cc717c710b3ff4ed7024e831c3b43
--- /dev/null
+++ b/test/Transforms/NaCl/pnacl-sjlj-eh-bug.ll
@@ -0,0 +1,81 @@
+; RUN: opt %s -pnacl-sjlj-eh -O2 -S | FileCheck %s
+
+; datalayout must be specified for GVN to work.
+target datalayout = "p:32:32:32"
+
+; This must be declared for expanding "invoke" and "landingpad" instructions.
+@__pnacl_eh_stack = external thread_local global i8*
+
+declare i1 @might_be_setjmp()
+declare void @external_func(i32* %ptr)
+declare void @var_is_nonzero()
+
+
+; Test for a bug in which PNaClSjLjEH would transform
+; @invoke_optimize_test() such that the call to @var_is_nonzero()
+; could get optimized away by a later optimization pass.  This
+; happened because PNaClSjLjEH generated code similar to
+; @branch_optimize_test() below.
+
+define void @invoke_optimize_test() {
+  %var = alloca i32
+  store i32 0, i32* %var
+
+  invoke void @external_func(i32* %var)
+      to label %exit unwind label %lpad
+
+lpad:
+  landingpad i32 personality i8* null
+      catch i8* null
+  %value = load i32* %var
+  %is_zero = icmp eq i32 %value, 0
+  br i1 %is_zero, label %exit, label %do_call
+
+do_call:
+  call void @var_is_nonzero()
+  ret void
+
+exit:
+  ret void
+}
+; CHECK: define void @invoke_optimize_test()
+; CHECK: @var_is_nonzero()
+
+
+; In @branch_optimize_test(), the optimizer can optimize away the call
+; to @var_is_nonzero(), because it can assume that %var always
+; contains 0 on the "iffalse" branch.
+;
+; The passes "-gvn -instcombine" are enough to do this.
+;
+; The optimizer can do this regardless of whether @might_be_setjmp()
+; is setjmp() or a normal function.  It doesn't need to know that
+; @might_be_setjmp() might return twice, because storing to %var
+; between setjmp() and longjmp() leaves %var pointing to an undefined
+; value.
+
+define void @branch_optimize_test() {
+  %var = alloca i32
+  store i32 0, i32* %var
+
+  %cond = call i1 @might_be_setjmp() returns_twice
+  br i1 %cond, label %iftrue, label %iffalse
+
+iftrue:
+  call void @external_func(i32* %var)
+  ret void
+
+iffalse:
+  %value = load i32* %var
+  %is_zero = icmp eq i32 %value, 0
+  br i1 %is_zero, label %exit, label %do_call
+
+do_call:
+  call void @var_is_nonzero()
+  ret void
+
+exit:
+  ret void
+}
+; CHECK: define void @branch_optimize_test()
+; CHECK-NOT: @var_is_nonzero