From 7f9bf43bcf197dc6a2a4bf44974776957de32e5a Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Tue, 24 Apr 2012 19:06:55 +0000
Subject: [PATCH] MachineBasicBlock::SplitCriticalEdge() should follow LLVM IR
 variant and refuse to break edge to EH landing pad. rdar://11300144

llvm-svn: 155470
---
 lib/CodeGen/MachineBasicBlock.cpp             |  5 ++
 .../ARM/2012-04-24-SplitEHCriticalEdge.ll     | 71 +++++++++++++++++++
 2 files changed, 76 insertions(+)
 create mode 100644 test/CodeGen/ARM/2012-04-24-SplitEHCriticalEdge.ll

diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index 1abb8f240cc..cf885251d6d 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -596,6 +596,11 @@ bool MachineBasicBlock::canFallThrough() {
 
 MachineBasicBlock *
 MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) {
+  // Splitting the critical edge to a landing pad block is non-trivial. Don't do
+  // it in this generic function.
+  if (Succ->isLandingPad())
+    return NULL;
+
   MachineFunction *MF = getParent();
   DebugLoc dl;  // FIXME: this is nowhere
 
diff --git a/test/CodeGen/ARM/2012-04-24-SplitEHCriticalEdge.ll b/test/CodeGen/ARM/2012-04-24-SplitEHCriticalEdge.ll
new file mode 100644
index 00000000000..b3a7e3444f3
--- /dev/null
+++ b/test/CodeGen/ARM/2012-04-24-SplitEHCriticalEdge.ll
@@ -0,0 +1,71 @@
+; RUN: llc -mtriple=thumbv7-apple-ios -relocation-model=pic -disable-fp-elim -mcpu=cortex-a8 < %s
+
+; CodeGen SplitCriticalEdge() shouldn't try to break edge to a landing pad.
+; rdar://11300144
+
+%0 = type opaque
+%class.FunctionInterpreter.3.15.31 = type { %class.Parser.1.13.29, %class.Parser.1.13.29*, %struct.ParserVariable.2.14.30*, i32 }
+%class.Parser.1.13.29 = type { i32 (...)**, %class.Parser.1.13.29* }
+%struct.ParserVariable.2.14.30 = type opaque
+%struct.ParseErrorMsg.0.12.28 = type { i32, i32, i32 }
+
+@_ZTI13ParseErrorMsg = external hidden unnamed_addr constant { i8*, i8* }
+@"OBJC_IVAR_$_MUMathExpressionDoubleBased.mInterpreter" = external hidden global i32, section "__DATA, __objc_ivar", align 4
+@"\01L_OBJC_SELECTOR_REFERENCES_14" = external hidden global i8*, section "__DATA, __objc_selrefs, literal_pointers, no_dead_strip"
+
+declare i8* @objc_msgSend(i8*, i8*, ...)
+
+declare i32 @llvm.eh.typeid.for(i8*) nounwind readnone
+
+declare i8* @__cxa_begin_catch(i8*)
+
+declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
+
+declare void @__cxa_end_catch()
+
+declare void @_ZSt9terminatev()
+
+define hidden double @t(%0* %self, i8* nocapture %_cmd) optsize ssp {
+entry:
+  %call = invoke double undef(%class.FunctionInterpreter.3.15.31* undef) optsize
+          to label %try.cont unwind label %lpad
+
+lpad:                                             ; preds = %entry
+  %0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_sj0 to i8*)
+          catch i8* bitcast ({ i8*, i8* }* @_ZTI13ParseErrorMsg to i8*)
+  br i1 undef, label %catch, label %eh.resume
+
+catch:                                            ; preds = %lpad
+  invoke void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (i8*, i8*, %struct.ParseErrorMsg.0.12.28*)*)(i8* undef, i8* undef, %struct.ParseErrorMsg.0.12.28* undef) optsize
+          to label %invoke.cont2 unwind label %lpad1
+
+invoke.cont2:                                     ; preds = %catch
+  br label %try.cont
+
+try.cont:                                         ; preds = %invoke.cont2, %entry
+  %value.0 = phi double [ 0x7FF8000000000000, %invoke.cont2 ], [ %call, %entry ]
+  ret double %value.0
+
+lpad1:                                            ; preds = %catch
+  %1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_sj0 to i8*)
+          cleanup
+  invoke void @__cxa_end_catch()
+          to label %eh.resume unwind label %terminate.lpad
+
+eh.resume:                                        ; preds = %lpad1, %lpad
+  resume { i8*, i32 } undef
+
+terminate.lpad:                                   ; preds = %lpad1
+  %2 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_sj0 to i8*)
+          catch i8* null
+  unreachable
+}
+
+declare i32 @__gxx_personality_sj0(...)
+
+!llvm.module.flags = !{!0, !1, !2, !3}
+
+!0 = metadata !{i32 1, metadata !"Objective-C Version", i32 2}
+!1 = metadata !{i32 1, metadata !"Objective-C Image Info Version", i32 0}
+!2 = metadata !{i32 1, metadata !"Objective-C Image Info Section", metadata !"__DATA, __objc_imageinfo, regular, no_dead_strip"}
+!3 = metadata !{i32 4, metadata !"Objective-C Garbage Collection", i32 0}