Fix a coaelescer bug. If a copy val# is extended to eliminate a non-trivially coalesced copy, and the copy kills its source register. Trim the source register's live range to the last use if possible. This fixes up kill marker to make the scavenger happy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77967 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 54 insertions, 1 deletions

diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index 1ff3af92fa..a2d521b139 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -123,7 +123,8 @@ bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(LiveInterval &IntA,
   assert(BValNo->def == CopyIdx && "Copy doesn't define the value?");
   
   // AValNo is the value number in A that defines the copy, A3 in the example.
-  LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyIdx-1);
+  unsigned CopyUseIdx = li_->getUseIndex(CopyIdx);
+  LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyUseIdx);
   assert(ALR != IntA.end() && "Live range not found!");
   VNInfo *AValNo = ALR->valno;
   // If it's re-defined by an early clobber somewhere in the live range, then
@@ -227,6 +228,12 @@ bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(LiveInterval &IntA,
     IntB.removeKill(ValLR->valno, FillerStart);
   }
 
+  // If the copy instruction was killing the destination register before the
+  // merge, find the last use and trim the live range. That will also add the
+  // isKill marker.
+  if (CopyMI->killsRegister(IntA.reg))
+    TrimLiveIntervalToLastUse(CopyUseIdx, CopyMI->getParent(), IntA, ALR);
+
   ++numExtends;
   return true;
 }
diff --git a/test/CodeGen/Thumb2/2009-08-02-CoalescerBug.ll b/test/CodeGen/Thumb2/2009-08-02-CoalescerBug.ll
new file mode 100644
index 0000000000..2f4683a43f
--- /dev/null
+++ b/test/CodeGen/Thumb2/2009-08-02-CoalescerBug.ll
@@ -0,0 +1,46 @@
+; RUN: llvm-as < %s | llc -mtriple=thumbv7-apple-darwin9 -mcpu=cortex-a8 -relocation-model=pic -disable-fp-elim
+
+	type { void (%"struct.xalanc_1_8::FormatterToXML"*, i16)*, i32 }		; type %0
+	type { void (%"struct.xalanc_1_8::FormatterToXML"*, i16*)*, i32 }		; type %1
+	type { void (%"struct.xalanc_1_8::FormatterToXML"*, %"struct.xalanc_1_8::XalanDOMString"*)*, i32 }		; type %2
+	type { void (%"struct.xalanc_1_8::FormatterToXML"*, i16*, i32, i32)*, i32 }		; type %3
+	type { void (%"struct.xalanc_1_8::FormatterToXML"*)*, i32 }		; type %4
+	%"struct.std::CharVectorType" = type { %"struct.std::_Vector_base<char,std::allocator<char> >" }
+	%"struct.std::_Bit_const_iterator" = type { %"struct.std::_Bit_iterator_base" }
+	%"struct.std::_Bit_iterator_base" = type { i32*, i32 }
+	%"struct.std::_Bvector_base<std::allocator<bool> >" = type { %"struct.std::_Bvector_base<std::allocator<bool> >::_Bvector_impl" }
+	%"struct.std::_Bvector_base<std::allocator<bool> >::_Bvector_impl" = type { %"struct.std::_Bit_const_iterator", %"struct.std::_Bit_const_iterator", i32* }
+	%"struct.std::_Vector_base<char,std::allocator<char> >" = type { %"struct.std::_Vector_base<char,std::allocator<char> >::_Vector_impl" }
+	%"struct.std::_Vector_base<char,std::allocator<char> >::_Vector_impl" = type { i8*, i8*, i8* }
+	%"struct.std::_Vector_base<short unsigned int,std::allocator<short unsigned int> >" = type { %"struct.std::_Vector_base<short unsigned int,std::allocator<short unsigned int> >::_Vector_impl" }
+	%"struct.std::_Vector_base<short unsigned int,std::allocator<short unsigned int> >::_Vector_impl" = type { i16*, i16*, i16* }
+	%"struct.std::basic_ostream<char,std::char_traits<char> >.base" = type { i32 (...)** }
+	%"struct.std::vector<bool,std::allocator<bool> >" = type { %"struct.std::_Bvector_base<std::allocator<bool> >" }
+	%"struct.std::vector<short unsigned int,std::allocator<short unsigned int> >" = type { %"struct.std::_Vector_base<short unsigned int,std::allocator<short unsigned int> >" }
+	%"struct.xalanc_1_8::FormatterListener" = type { %"struct.std::basic_ostream<char,std::char_traits<char> >.base", %"struct.std::basic_ostream<char,std::char_traits<char> >.base"*, i32 }
+	%"struct.xalanc_1_8::FormatterToXML" = type { %"struct.xalanc_1_8::FormatterListener", %"struct.std::basic_ostream<char,std::char_traits<char> >.base"*, %"struct.xalanc_1_8::XalanOutputStream"*, i16, [256 x i16], [256 x i16], i8, i8, i8, i8, i8, i8, i8, i8, i8, i8, %"struct.xalanc_1_8::XalanDOMString", %"struct.xalanc_1_8::XalanDOMString", %"struct.xalanc_1_8::XalanDOMString", i32, i32, %"struct.std::vector<bool,std::allocator<bool> >", %"struct.xalanc_1_8::XalanDOMString", i8, i8, i8, i8, i8, %"struct.xalanc_1_8::XalanDOMString", %"struct.xalanc_1_8::XalanDOMString", %"struct.xalanc_1_8::XalanDOMString", %"struct.xalanc_1_8::XalanDOMString", %"struct.std::vector<short unsigned int,std::allocator<short unsigned int> >", i32, %"struct.std::CharVectorType", %"struct.std::vector<bool,std::allocator<bool> >", %0, %1, %2, %3, %0, %1, %2, %3, %4, i16*, i32 }
+	%"struct.xalanc_1_8::XalanDOMString" = type { %"struct.std::vector<short unsigned int,std::allocator<short unsigned int> >", i32 }
+	%"struct.xalanc_1_8::XalanOutputStream" = type { i32 (...)**, i32, %"struct.std::basic_ostream<char,std::char_traits<char> >.base"*, i32, %"struct.std::vector<short unsigned int,std::allocator<short unsigned int> >", %"struct.xalanc_1_8::XalanDOMString", i8, i8, %"struct.std::CharVectorType" }
+
+declare arm_apcscc void @_ZN10xalanc_1_814FormatterToXML17writeParentTagEndEv(%"struct.xalanc_1_8::FormatterToXML"*)
+
+define arm_apcscc void @_ZN10xalanc_1_814FormatterToXML5cdataEPKtj(%"struct.xalanc_1_8::FormatterToXML"* %this, i16* %ch, i32 %length) {
+entry:
+	%0 = getelementptr %"struct.xalanc_1_8::FormatterToXML"* %this, i32 0, i32 13		; <i8*> [#uses=1]
+	br i1 undef, label %bb4, label %bb
+
+bb:		; preds = %entry
+	store i8 0, i8* %0, align 1
+	%1 = getelementptr %"struct.xalanc_1_8::FormatterToXML"* %this, i32 0, i32 0, i32 0, i32 0		; <i32 (...)***> [#uses=1]
+	%2 = load i32 (...)*** %1, align 4		; <i32 (...)**> [#uses=1]
+	%3 = getelementptr i32 (...)** %2, i32 11		; <i32 (...)**> [#uses=1]
+	%4 = load i32 (...)** %3, align 4		; <i32 (...)*> [#uses=1]
+	%5 = bitcast i32 (...)* %4 to void (%"struct.xalanc_1_8::FormatterToXML"*, i16*, i32)*		; <void (%"struct.xalanc_1_8::FormatterToXML"*, i16*, i32)*> [#uses=1]
+	tail call arm_apcscc  void %5(%"struct.xalanc_1_8::FormatterToXML"* %this, i16* %ch, i32 %length)
+	ret void
+
+bb4:		; preds = %entry
+	tail call arm_apcscc  void @_ZN10xalanc_1_814FormatterToXML17writeParentTagEndEv(%"struct.xalanc_1_8::FormatterToXML"* %this)
+	tail call arm_apcscc  void undef(%"struct.xalanc_1_8::FormatterToXML"* %this, i16* %ch, i32 0, i32 %length, i8 zeroext undef)
+	ret void
+}