[WinEH] Don't forward branches across empty EH pad BBs
For really simple SEH catchpads, we tried to forward the invoke unwind
edge across the empty block.
llvm-svn: 252822
diff --git a/llvm/test/CodeGen/X86/catchret-empty-fallthrough.ll b/llvm/test/CodeGen/X86/catchret-empty-fallthrough.ll
new file mode 100644
index 0000000..3b3b3f5
--- /dev/null
+++ b/llvm/test/CodeGen/X86/catchret-empty-fallthrough.ll
@@ -0,0 +1,53 @@
+; RUN: llc -verify-machineinstrs < %s | FileCheck %s
+
+; BranchFolding used to remove our empty landingpad block, which is
+; undesirable.
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc18.0.0"
+
+declare i32 @__C_specific_handler(...)
+
+declare void @bar()
+
+define void @foo(i1 %cond) personality i32 (...)* @__C_specific_handler {
+entry:
+ br i1 %cond, label %return, label %try
+
+try: ; preds = %entry
+ invoke void @bar()
+ to label %fallthrough unwind label %dispatch
+
+dispatch: ; preds = %try
+ %0 = catchpad [i8* null]
+ to label %catch unwind label %catchendblock.i.i
+
+catch: ; preds = %dispatch
+ catchret %0 to label %return
+
+catchendblock.i.i: ; preds = %dispatch
+ catchendpad unwind to caller
+
+fallthrough: ; preds = %try
+ unreachable
+
+return: ; preds = %catch, %entry
+ ret void
+}
+
+; CHECK-LABEL: foo: # @foo
+; CHECK: testb $1, %cl
+; CHECK: jne .LBB0_[[return:[0-9]+]]
+; CHECK: .Ltmp0:
+; CHECK: callq bar
+; CHECK: .Ltmp1:
+; CHECK: .LBB0_[[catch:[0-9]+]]:
+; CHECK: .LBB0_[[return]]:
+
+; CHECK: .seh_handlerdata
+; CHECK-NEXT: .long (.Llsda_end0-.Llsda_begin0)/16
+; CHECK-NEXT: .Llsda_begin0:
+; CHECK-NEXT: .long .Ltmp0@IMGREL+1
+; CHECK-NEXT: .long .Ltmp1@IMGREL+1
+; CHECK-NEXT: .long 1
+; CHECK-NEXT: .long .LBB0_[[catch]]@IMGREL