[WinEH] Demote values and phis live across exception handlers up front

In particular, this handles SSA values that are live *out* of a handler.
The existing code only handles values that are live *in* to a handler.

It also handles phi nodes in the block where normal control should
resume after the end of a catch handler.  When EH return points have phi
nodes, we need to split the return edge. It is impossible for phi
elimination to emit copies in the previous block if that block gets
outlined. The indirectbr that we leave in the function is only notional,
and is eliminated from the MachineFunction CFG early on.

Reviewers: majnemer, andrew.w.kaylor

Differential Revision: http://reviews.llvm.org/D9158

llvm-svn: 235545

1 files changed, 14 insertions, 17 deletions

diff --git a/llvm/test/CodeGen/WinEH/cppeh-multi-catch.ll b/llvm/test/CodeGen/WinEH/cppeh-multi-catch.ll
index 6052629198c..9844eb5735c 100644
--- a/llvm/test/CodeGen/WinEH/cppeh-multi-catch.ll
+++ b/llvm/test/CodeGen/WinEH/cppeh-multi-catch.ll
@@ -79,7 +79,7 @@ invoke.cont:                                      ; preds = %entry
 ; CHECK-SAME:        i32 1, i8* bitcast (%eh.HandlerMapEntry* @llvm.eh.handlermapentry._J to i8*), i32 1, i8* (i8*, i8*)* @"\01?test@@YAXXZ.catch1",
 ; CHECK-SAME:        i32 1, i8* bitcast (%eh.HandlerMapEntry* @"llvm.eh.handlermapentry.reference.?AVSomeClass@@" to i8*), i32 2, i8* (i8*, i8*)* @"\01?test@@YAXXZ.catch2",
 ; CHECK-SAME:        i32 1, i8* null, i32 -1, i8* (i8*, i8*)* @"\01?test@@YAXXZ.catch3")
-; CHECK-NEXT:   indirectbr i8* [[RECOVER]], [label %catch14.split, label %catch10.split, label %catch6.split, label %catch.split]
+; CHECK-NEXT:   indirectbr i8* [[RECOVER]], [label %ret]
 
 lpad:                                             ; preds = %entry
   %0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*)
@@ -100,8 +100,11 @@ catch.dispatch:                                   ; preds = %lpad
   %matches = icmp eq i32 %sel, %3
   br i1 %matches, label %catch14, label %catch.fallthrough
 
+ret:
+  ret void
+
 ; CHECK-NOT: catch14:
-; CHECK: catch14.split:
+; CHECK: ret:
 ; CHECK-NEXT:   ret void
 catch14:                                          ; preds = %catch.dispatch
   %exn15 = load i8*, i8** %exn.slot
@@ -110,10 +113,10 @@ catch14:                                          ; preds = %catch.dispatch
   %5 = load i32, i32* %i, align 4
   call void @"\01?handle_int@@YAXH@Z"(i32 %5)
   call void @llvm.eh.endcatch() #3
-  ret void
+  br label %ret
 
 try.cont:                                         ; preds = %invoke.cont
-  ret void
+  br label %ret
 
 ; CHECK-NOT: catch.fallthrough:
 catch.fallthrough:                                ; preds = %catch.dispatch
@@ -122,8 +125,6 @@ catch.fallthrough:                                ; preds = %catch.dispatch
   br i1 %matches1, label %catch10, label %catch.fallthrough2
 
 ; CHECK-NOT: catch10:
-; CHECK: catch10.split:
-; CHECK-NEXT:   ret void
 catch10:                                          ; preds = %catch.fallthrough
   %exn11 = load i8*, i8** %exn.slot
   %7 = bitcast i64* %ll to i8*
@@ -131,7 +132,7 @@ catch10:                                          ; preds = %catch.fallthrough
   %8 = load i64, i64* %ll, align 8
   call void @"\01?handle_long_long@@YAX_J@Z"(i64 %8)
   call void @llvm.eh.endcatch() #3
-  ret void
+  br label %ret
 
 ; CHECK-NOT: catch.fallthrough2:
 catch.fallthrough2:                               ; preds = %catch.fallthrough
@@ -140,8 +141,6 @@ catch.fallthrough2:                               ; preds = %catch.fallthrough
   br i1 %matches3, label %catch6, label %catch
 
 ; CHECK-NOT: catch6:
-; CHECK: catch6.split:
-; CHECK-NEXT:   ret void
 catch6:                                           ; preds = %catch.fallthrough2
   %exn7 = load i8*, i8** %exn.slot
   %10 = bitcast %class.SomeClass** %obj to i8*
@@ -149,16 +148,14 @@ catch6:                                           ; preds = %catch.fallthrough2
   %11 = load %class.SomeClass*, %class.SomeClass** %obj, align 8
   call void @"\01?handle_obj@@YAXPEAVSomeClass@@@Z"(%class.SomeClass* %11)
   call void @llvm.eh.endcatch() #3
-  ret void
+  br label %ret
 
 ; CHECK-NOT: catch:
-; CHECK: catch.split:
-; CHECK-NEXT:   ret void
 catch:                                            ; preds = %catch.fallthrough2
   %exn = load i8*, i8** %exn.slot
   call void @llvm.eh.begincatch(i8* %exn, i8* null) #3
   call void @"\01?handle_exception@@YAXXZ"()  call void @llvm.eh.endcatch() #3
-  ret void
+  br label %ret
 ; CHECK: }
 }
 
@@ -168,7 +165,7 @@ catch:                                            ; preds = %catch.fallthrough2
 ; CHECK:   [[I_PTR:\%.+]] = bitcast i8* [[RECOVER_I]] to i32*
 ; CHECK:   [[TMP1:\%.+]] = load i32, i32* [[I_PTR]], align 4
 ; CHECK:   call void @"\01?handle_int@@YAXH@Z"(i32 [[TMP1]])
-; CHECK:   ret i8* blockaddress(@"\01?test@@YAXXZ", %catch14.split)
+; CHECK:   ret i8* blockaddress(@"\01?test@@YAXXZ", %ret)
 ; CHECK: }
 
 ; CHECK-LABEL: define internal i8* @"\01?test@@YAXXZ.catch1"(i8*, i8*)
@@ -177,7 +174,7 @@ catch:                                            ; preds = %catch.fallthrough2
 ; CHECK:   [[LL_PTR:\%.+]] = bitcast i8* [[RECOVER_LL]] to i64*
 ; CHECK:   [[TMP2:\%.+]] = load i64, i64* [[LL_PTR]], align 8
 ; CHECK:   call void @"\01?handle_long_long@@YAX_J@Z"(i64 [[TMP2]])
-; CHECK:   ret i8* blockaddress(@"\01?test@@YAXXZ", %catch10.split)
+; CHECK:   ret i8* blockaddress(@"\01?test@@YAXXZ", %ret)
 ; CHECK: }
 
 ; CHECK-LABEL: define internal i8* @"\01?test@@YAXXZ.catch2"(i8*, i8*)
@@ -186,13 +183,13 @@ catch:                                            ; preds = %catch.fallthrough2
 ; CHECK:   [[OBJ_PTR:\%.+]] = bitcast i8* [[RECOVER_OBJ]] to %class.SomeClass**
 ; CHECK:   [[TMP3:\%.+]] = load %class.SomeClass*, %class.SomeClass** [[OBJ_PTR]], align 8
 ; CHECK:   call void @"\01?handle_obj@@YAXPEAVSomeClass@@@Z"(%class.SomeClass* [[TMP3]])
-; CHECK:   ret i8* blockaddress(@"\01?test@@YAXXZ", %catch6.split)
+; CHECK:   ret i8* blockaddress(@"\01?test@@YAXXZ", %ret)
 ; CHECK: }
 
 ; CHECK-LABEL: define internal i8* @"\01?test@@YAXXZ.catch3"(i8*, i8*)
 ; CHECK: entry:
 ; CHECK:   call void @"\01?handle_exception@@YAXXZ"()
-; CHECK:   ret i8* blockaddress(@"\01?test@@YAXXZ", %catch.split)
+; CHECK:   ret i8* blockaddress(@"\01?test@@YAXXZ", %ret)
 ; CHECK: }