Fix PR16110: Handle DBG_VALUE in ConnectedVNInfoEqClasses::Distribute().

Now that the LiveDebugVariables pass is running *after* register
coalescing, the ConnectedVNInfoEqClasses class needs to deal with
DBG_VALUE instructions.

This only comes up when rematerialization during coalescing causes the
remaining live range of a virtual register to separate into two
connected components.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182592 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 123 insertions, 2 deletions

diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index dccd847..861e99b 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -909,8 +909,16 @@ void ConnectedVNInfoEqClasses::Distribute(LiveInterval *LIV[],
     MachineOperand &MO = RI.getOperand();
     MachineInstr *MI = MO.getParent();
     ++RI;
-    // DBG_VALUE instructions should have been eliminated earlier.
-    LiveRangeQuery LRQ(LI, LIS.getInstructionIndex(MI));
+    // DBG_VALUE instructions don't have slot indexes, so get the index of the
+    // instruction before them.
+    // Normally, DBG_VALUE instructions are removed before this function is
+    // called, but it is not a requirement.
+    SlotIndex Idx;
+    if (MI->isDebugValue())
+      Idx = LIS.getSlotIndexes()->getIndexBefore(MI);
+    else
+      Idx = LIS.getInstructionIndex(MI);
+    LiveRangeQuery LRQ(LI, Idx);
     const VNInfo *VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
     // In the case of an <undef> use that isn't tied to any def, VNI will be
     // NULL. If the use is tied to a def, VNI will be the defined value.
diff --git a/test/CodeGen/ARM/coalesce-dbgvalue.ll b/test/CodeGen/ARM/coalesce-dbgvalue.ll
new file mode 100644
index 0000000..d4be6ee
--- /dev/null
+++ b/test/CodeGen/ARM/coalesce-dbgvalue.ll
@@ -0,0 +1,113 @@
+; RUN: llc < %s -verify-machineinstrs
+; PR16110
+;
+; This test case contains a value that is split into two connected components
+; by rematerialization during coalescing. It also contains a DBG_VALUE
+; instruction which must be updated during
+; ConnectedVNInfoEqClasses::Distribute().
+
+target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n32-S32"
+target triple = "thumbv7-apple-ios3.0.0"
+
+@c = common global i32 0, align 4
+@b = common global i32 0, align 4
+@a = common global i64 0, align 8
+@d = common global i32 0, align 4
+
+; Function Attrs: nounwind ssp
+define i32 @pr16110() #0 {
+for.cond1.preheader:
+  store i32 0, i32* @c, align 4, !dbg !21, !tbaa !23
+  br label %for.cond1.outer, !dbg !26
+
+for.cond1:                                        ; preds = %for.end9, %for.cond1.outer
+  %storemerge11 = phi i32 [ 0, %for.end9 ], [ %storemerge11.ph, %for.cond1.outer ]
+  %cmp = icmp slt i32 %storemerge11, 1, !dbg !26
+  br i1 %cmp, label %for.body2, label %for.end9, !dbg !26
+
+for.body2:                                        ; preds = %for.cond1
+  store i32 %storemerge11, i32* @b, align 4, !dbg !26, !tbaa !23
+  tail call void @llvm.dbg.value(metadata !27, i64 0, metadata !11), !dbg !28
+  %0 = load i64* @a, align 8, !dbg !29, !tbaa !30
+  %xor = xor i64 %0, %e.1.ph, !dbg !29
+  %conv3 = trunc i64 %xor to i32, !dbg !29
+  tail call void @llvm.dbg.value(metadata !{i32 %conv3}, i64 0, metadata !10), !dbg !29
+  %tobool4 = icmp eq i32 %conv3, 0, !dbg !29
+  br i1 %tobool4, label %land.end, label %land.rhs, !dbg !29
+
+land.rhs:                                         ; preds = %for.body2
+  %call = tail call i32 bitcast (i32 (...)* @fn3 to i32 ()*)() #3, !dbg !29
+  %tobool5 = icmp ne i32 %call, 0, !dbg !29
+  br label %land.end
+
+land.end:                                         ; preds = %land.rhs, %for.body2
+  %1 = phi i1 [ false, %for.body2 ], [ %tobool5, %land.rhs ]
+  %land.ext = zext i1 %1 to i32
+  %call6 = tail call i32 bitcast (i32 (...)* @fn2 to i32 (i32, i32*)*)(i32 %land.ext, i32* null) #3
+  %2 = load i32* @b, align 4, !dbg !26, !tbaa !23
+  %inc8 = add nsw i32 %2, 1, !dbg !26
+  %phitmp = and i64 %xor, 4294967295, !dbg !26
+  br label %for.cond1.outer, !dbg !26
+
+for.cond1.outer:                                  ; preds = %land.end, %for.cond1.preheader
+  %storemerge11.ph = phi i32 [ %inc8, %land.end ], [ 0, %for.cond1.preheader ]
+  %e.1.ph = phi i64 [ %phitmp, %land.end ], [ 0, %for.cond1.preheader ]
+  %3 = load i32* @d, align 4, !dbg !31, !tbaa !23
+  %tobool10 = icmp eq i32 %3, 0, !dbg !31
+  br label %for.cond1
+
+for.end9:                                         ; preds = %for.cond1
+  br i1 %tobool10, label %if.end, label %for.cond1, !dbg !31
+
+if.end:                                           ; preds = %for.end9
+  store i32 %storemerge11, i32* @b, align 4, !dbg !26, !tbaa !23
+  ret i32 0, !dbg !32
+}
+
+declare i32 @fn2(...) #1
+
+declare i32 @fn3(...) #1
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata) #2
+
+attributes #0 = { nounwind ssp "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #2 = { nounwind readnone }
+attributes #3 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+
+!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.4 (trunk 182024) (llvm/trunk 182023)", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !15, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] [/d/b/pr16110.c] [DW_LANG_C99]
+!1 = metadata !{metadata !"pr16110.c", metadata !"/d/b"}
+!2 = metadata !{i32 0}
+!3 = metadata !{metadata !4}
+!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"pr16110", metadata !"pr16110", metadata !"", i32 7, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 0, i1 true, i32 ()* @pr16110, null, null, metadata !9, i32 7} ; [ DW_TAG_subprogram ] [line 7] [def] [pr16110]
+!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [/d/b/pr16110.c]
+!6 = metadata !{i32 786453, i32 0, i32 0, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!7 = metadata !{metadata !8}
+!8 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!9 = metadata !{metadata !10, metadata !11}
+!10 = metadata !{i32 786688, metadata !4, metadata !"e", metadata !5, i32 8, metadata !8, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [e] [line 8]
+!11 = metadata !{i32 786688, metadata !12, metadata !"f", metadata !5, i32 13, metadata !14, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [f] [line 13]
+!12 = metadata !{i32 786443, metadata !1, metadata !13, i32 12, i32 0, i32 2} ; [ DW_TAG_lexical_block ] [/d/b/pr16110.c]
+!13 = metadata !{i32 786443, metadata !1, metadata !4, i32 12, i32 0, i32 1} ; [ DW_TAG_lexical_block ] [/d/b/pr16110.c]
+!14 = metadata !{i32 786447, null, null, metadata !"", i32 0, i64 32, i64 32, i64 0, i32 0, metadata !8} ; [ DW_TAG_pointer_type ] [line 0, size 32, align 32, offset 0] [from int]
+!15 = metadata !{metadata !16, metadata !18, metadata !19, metadata !20}
+!16 = metadata !{i32 786484, i32 0, null, metadata !"a", metadata !"a", metadata !"", metadata !5, i32 1, metadata !17, i32 0, i32 1, i64* @a, null} ; [ DW_TAG_variable ] [a] [line 1] [def]
+!17 = metadata !{i32 786468, null, null, metadata !"long long int", i32 0, i64 64, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [long long int] [line 0, size 64, align 32, offset 0, enc DW_ATE_signed]
+!18 = metadata !{i32 786484, i32 0, null, metadata !"b", metadata !"b", metadata !"", metadata !5, i32 2, metadata !8, i32 0, i32 1, i32* @b, null} ; [ DW_TAG_variable ] [b] [line 2] [def]
+!19 = metadata !{i32 786484, i32 0, null, metadata !"c", metadata !"c", metadata !"", metadata !5, i32 3, metadata !8, i32 0, i32 1, i32* @c, null} ; [ DW_TAG_variable ] [c] [line 3] [def]
+!20 = metadata !{i32 786484, i32 0, null, metadata !"d", metadata !"d", metadata !"", metadata !5, i32 4, metadata !8, i32 0, i32 1, i32* @d, null} ; [ DW_TAG_variable ] [d] [line 4] [def]
+!21 = metadata !{i32 10, i32 0, metadata !22, null}
+!22 = metadata !{i32 786443, metadata !1, metadata !4, i32 10, i32 0, i32 0} ; [ DW_TAG_lexical_block ] [/d/b/pr16110.c]
+!23 = metadata !{metadata !"int", metadata !24}
+!24 = metadata !{metadata !"omnipotent char", metadata !25}
+!25 = metadata !{metadata !"Simple C/C++ TBAA"}
+!26 = metadata !{i32 12, i32 0, metadata !13, null}
+!27 = metadata !{i32* null}
+!28 = metadata !{i32 13, i32 0, metadata !12, null}
+!29 = metadata !{i32 14, i32 0, metadata !12, null}
+!30 = metadata !{metadata !"long long", metadata !24}
+!31 = metadata !{i32 16, i32 0, metadata !4, null}
+!32 = metadata !{i32 18, i32 0, metadata !4, null}