Fix 12892.

Dead code elimination during coalescing could cause a virtual register
to be split into connected components. The following rewriting would be
confused about the already joined copies present in the code, but
without a corresponding value number in the live range.

Erase all joined copies instantly when joining intervals such that the
MI and LiveInterval representations are always in sync.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157135 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 122 insertions, 0 deletions

diff --git a/test/CodeGen/X86/2012-05-19-CoalescerCrash.ll b/test/CodeGen/X86/2012-05-19-CoalescerCrash.ll
new file mode 100644
index 0000000000..837fbc0777
--- /dev/null
+++ b/test/CodeGen/X86/2012-05-19-CoalescerCrash.ll
@@ -0,0 +1,122 @@
+; RUN: llc < %s -verify-coalescing
+; PR12892
+;
+; Dead code elimination during coalesing causes a live range to split into two
+; virtual registers. Stale identity copies that had already been joined were
+; interfering with the liveness computations.
+
+target triple = "i386-pc-linux-gnu"
+
+define void @_ZN4llvm17AsmMatcherEmitter3runERNS_11raw_ostreamE() align 2 {
+  invoke void @_ZNK4llvm13CodeGenTarget12getAsmParserEv()
+          to label %1 unwind label %5
+
+; <label>:1                                       ; preds = %0
+  invoke void @_ZNK4llvm6Record16getValueAsStringENS_9StringRefE()
+          to label %4 unwind label %2
+
+; <label>:2                                       ; preds = %1
+  %3 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          cleanup
+  unreachable
+
+; <label>:4                                       ; preds = %1
+  invoke void @_ZN4llvm18isCurrentDebugTypeEPKc()
+          to label %12 unwind label %7
+
+; <label>:5                                       ; preds = %0
+  %6 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          cleanup
+  br label %33
+
+; <label>:7                                       ; preds = %4
+  %8 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          cleanup
+  br label %9
+
+; <label>:9                                       ; preds = %28, %7
+  %10 = phi { i8*, i32 } [ %29, %28 ], [ %8, %7 ]
+  %11 = extractvalue { i8*, i32 } %10, 1
+  invoke fastcc void @_ZN12_GLOBAL__N_114AsmMatcherInfoD2Ev()
+          to label %32 unwind label %35
+
+; <label>:12                                      ; preds = %4
+  invoke void @_ZNK4llvm13CodeGenTarget10getRegBankEv()
+          to label %13 unwind label %16
+
+; <label>:13                                      ; preds = %12
+  br label %14
+
+; <label>:14                                      ; preds = %20, %13
+  %15 = icmp eq i32 undef, 0
+  br i1 %15, label %20, label %18
+
+; <label>:16                                      ; preds = %12
+  %17 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          cleanup
+  br label %26
+
+; <label>:18                                      ; preds = %14
+  invoke void @_ZNSs4_Rep9_S_createEjjRKSaIcE()
+          to label %19 unwind label %21
+
+; <label>:19                                      ; preds = %18
+  unreachable
+
+; <label>:20                                      ; preds = %14
+  br label %14
+
+; <label>:21                                      ; preds = %18
+  %22 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          cleanup
+  %23 = extractvalue { i8*, i32 } %22, 1
+  br i1 undef, label %26, label %24
+
+; <label>:24                                      ; preds = %21
+  br i1 undef, label %25, label %26
+
+; <label>:25                                      ; preds = %24
+  unreachable
+
+; <label>:26                                      ; preds = %24, %21, %16
+  %27 = phi i32 [ 0, %16 ], [ %23, %21 ], [ %23, %24 ]
+  invoke void @_ZNSt6vectorISt4pairISsSsESaIS1_EED1Ev()
+          to label %28 unwind label %30
+
+; <label>:28                                      ; preds = %26
+  %29 = insertvalue { i8*, i32 } undef, i32 %27, 1
+  br label %9
+
+; <label>:30                                      ; preds = %26
+  %31 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          catch i8* null
+  unreachable
+
+; <label>:32                                      ; preds = %9
+  br label %33
+
+; <label>:33                                      ; preds = %32, %5
+  %34 = phi i32 [ undef, %5 ], [ %11, %32 ]
+  unreachable
+
+; <label>:35                                      ; preds = %9
+  %36 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          catch i8* null
+  unreachable
+}
+
+declare void @_ZNK4llvm13CodeGenTarget12getAsmParserEv()
+
+declare i32 @__gxx_personality_v0(...)
+
+declare void @_ZNK4llvm6Record16getValueAsStringENS_9StringRefE()
+
+declare void @_ZN4llvm18isCurrentDebugTypeEPKc()
+
+declare fastcc void @_ZN12_GLOBAL__N_114AsmMatcherInfoD2Ev() unnamed_addr inlinehint align 2
+
+declare hidden void @_ZNSt6vectorISt4pairISsSsESaIS1_EED1Ev() unnamed_addr align 2
+
+declare void @_ZNSs4_Rep9_S_createEjjRKSaIcE()
+
+declare void @_ZNK4llvm13CodeGenTarget10getRegBankEv()