[LoopSimplify] Set proper debug location in loop backedge blocks.

Set debug location for terminator instruction in loop backedge block
(which is an unconditional jump to loop header). We can't copy debug
location from original backedges, as there can be several of them,
with different debug info locations. So, we follow the approach of
SplitBlockPredecessors, and copy the debug info from first non-PHI
instruction in the header (i.e. destination block).

This is yet another change for PR23837.

llvm-svn: 240999

diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index d8f7c91..2e7d21c 100644 (file)
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -386,8 +386,9 @@ static BasicBlock *insertUniqueBackedgeBlock(Loop *L, BasicBlock *Preheader,
 
   // Create and insert the new backedge block...
   BasicBlock *BEBlock = BasicBlock::Create(Header->getContext(),
-                                           Header->getName()+".backedge", F);
+                                           Header->getName() + ".backedge", F);
   BranchInst *BETerminator = BranchInst::Create(Header, BEBlock);
+  BETerminator->setDebugLoc(Header->getFirstNonPHI()->getDebugLoc());
 
   DEBUG(dbgs() << "LoopSimplify: Inserting unique backedge block "
                << BEBlock->getName() << "\n");

diff --git a/llvm/test/Transforms/LoopSimplify/single-backedge.ll b/llvm/test/Transforms/LoopSimplify/single-backedge.ll
index aedd6f2..92fbdca 100644 (file)
--- a/llvm/test/Transforms/LoopSimplify/single-backedge.ll
+++ b/llvm/test/Transforms/LoopSimplify/single-backedge.ll
@@ -5,19 +5,35 @@
 ; RUN: opt < %s -indvars -S | FileCheck %s
 ; CHECK: Loop.backedge:
 ; CHECK-NOT: br
-; CHECK: br label %Loop
+; CHECK: br label %Loop, !dbg [[BACKEDGE_LOC:![0-9]+]]
+
+; CHECK: [[BACKEDGE_LOC]] = !DILocation(line: 101, column: 1, scope: !{{.*}})
 
 define i32 @test(i1 %C) {
 ; <label>:0
-       br label %Loop
-Loop:          ; preds = %BE2, %BE1, %0
-       %IV = phi i32 [ 1, %0 ], [ %IV2, %BE1 ], [ %IV2, %BE2 ]         ; <i32> [#uses=2]
-       store i32 %IV, i32* null
-       %IV2 = add i32 %IV, 2           ; <i32> [#uses=2]
-       br i1 %C, label %BE1, label %BE2
-BE1:           ; preds = %Loop
-       br label %Loop
-BE2:           ; preds = %Loop
-       br label %Loop
+  br label %Loop, !dbg !6
+Loop: ; preds = %BE2, %BE1, %0
+  %IV = phi i32 [ 1, %0 ], [ %IV2, %BE1 ], [ %IV2, %BE2 ] ; <i32> [#uses=2]
+  store i32 %IV, i32* null, !dbg !7
+  %IV2 = add i32 %IV, 2, !dbg !8 ; <i32> [#uses=2]
+  br i1 %C, label %BE1, label %BE2, !dbg !9
+BE1:  ; preds = %Loop
+  br label %Loop, !dbg !10
+BE2:    ; preds = %n br label %Loop
+  br label %Loop, !dbg !11
 }
 
+!llvm.module.flags = !{!0, !1}
+!0 = !{i32 2, !"Dwarf Version", i32 4}
+!1 = !{i32 2, !"Debug Info Version", i32 3}
+
+!2 = !{}
+!3 = !DISubroutineType(types: !2)
+!4 = !DIFile(filename: "atomic.cpp", directory: "/tmp")
+!5 = !DISubprogram(name: "test", scope: !4, file: !4, line: 99, type: !3, isLocal: false, isDefinition: true, scopeLine: 100, flags: DIFlagPrototyped, isOptimized: false, variables: !2)
+!6 = !DILocation(line: 100, column: 1, scope: !5)
+!7 = !DILocation(line: 101, column: 1, scope: !5)
+!8 = !DILocation(line: 102, column: 1, scope: !5)
+!9 = !DILocation(line: 103, column: 1, scope: !5)
+!10 = !DILocation(line: 104, column: 1, scope: !5)
+!11 = !DILocation(line: 105, column: 1, scope: !5)