[llvm] r298213 - Enable stripping of multiple DILocation on !llvm.loop metadata

[Teresa Johnson via llvm-commits]

Author: tejohnson
Date: Sun Mar 19 08:54:57 2017
New Revision: 298213

URL: http://llvm.org/viewvc/llvm-project?rev=298213&view=rev
Log:
Enable stripping of multiple DILocation on !llvm.loop metadata

Summary:
I found that stripDebugInfo was still leaving significant amounts of
debug info due to !llvm.loop that contained DILocation after stripping.
The support for stripping debug info on !llvm.loop added in r293377 only
removes a single DILocation. Enhance that to remove all DILocation from
!llvm.loop.

Reviewers: hfinkel, aprantl, dsanders

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31117

Modified:
    llvm/trunk/lib/IR/DebugInfo.cpp
    llvm/trunk/test/DebugInfo/strip-loop-metadata.ll

Modified: llvm/trunk/lib/IR/DebugInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/DebugInfo.cpp?rev=298213&r1=298212&r2=298213&view=diff
==============================================================================
--- llvm/trunk/lib/IR/DebugInfo.cpp (original)
+++ llvm/trunk/lib/IR/DebugInfo.cpp Sun Mar 19 08:54:57 2017
@@ -241,26 +241,29 @@ bool DebugInfoFinder::addScope(DIScope *
 
 static llvm::MDNode *stripDebugLocFromLoopID(llvm::MDNode *N) {
   assert(N->op_begin() != N->op_end() && "Missing self reference?");
-  auto DebugLocOp =
-      std::find_if(N->op_begin() + 1, N->op_end(), [](const MDOperand &Op) {
-        return isa<DILocation>(Op.get());
-      });
 
-  // No debug location, we do not have to rewrite this MDNode.
-  if (DebugLocOp == N->op_end())
+  // if there is no debug location, we do not have to rewrite this MDNode.
+  if (std::none_of(N->op_begin() + 1, N->op_end(), [](const MDOperand &Op) {
+        return isa<DILocation>(Op.get());
+      }))
     return N;
 
-  // There is only the debug location without any actual loop metadata, hence we
+  // If there is only the debug location without any actual loop metadata, we
   // can remove the metadata.
-  if (N->getNumOperands() == 2)
+  if (std::none_of(N->op_begin() + 1, N->op_end(), [](const MDOperand &Op) {
+        return !isa<DILocation>(Op.get());
+      }))
     return nullptr;
 
   SmallVector<Metadata *, 4> Args;
   // Reserve operand 0 for loop id self reference.
   auto TempNode = MDNode::getTemporary(N->getContext(), None);
   Args.push_back(TempNode.get());
-  Args.append(N->op_begin() + 1, DebugLocOp);
-  Args.append(DebugLocOp + 1, N->op_end());
+  // Add all non-debug location operands back.
+  for (auto Op = N->op_begin() + 1; Op != N->op_end(); Op++) {
+    if (!isa<DILocation>(*Op))
+      Args.push_back(*Op);
+  }
 
   // Set the first operand to itself.
   MDNode *LoopID = MDNode::get(N->getContext(), Args);

Modified: llvm/trunk/test/DebugInfo/strip-loop-metadata.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/strip-loop-metadata.ll?rev=298213&r1=298212&r2=298213&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/strip-loop-metadata.ll (original)
+++ llvm/trunk/test/DebugInfo/strip-loop-metadata.ll Sun Mar 19 08:54:57 2017
@@ -33,6 +33,34 @@ return:
   ret void, !dbg !21
 }
 
+; CHECK-LABEL: _Z5test3v
+; CHECK: br {{.*}} !llvm.loop [[LOOP2:![0-9]+]]
+define void @_Z5test3v() !dbg !22 {
+entry:
+  br label %while.body, !dbg !23
+
+while.body:
+  call void @_Z3barv(), !dbg !24
+  br label %while.body, !dbg !25, !llvm.loop !26
+
+return:
+  ret void, !dbg !28
+}
+
+; CHECK-LABEL: _Z5test4v
+; CHECK-NOT: br {{.*}} !llvm.loop
+define void @_Z5test4v() !dbg !30 {
+entry:
+  br label %while.body, !dbg !31
+
+while.body:
+  call void @_Z3barv(), !dbg !32
+  br label %while.body, !dbg !33, !llvm.loop !34
+
+return:
+  ret void, !dbg !36
+}
+
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!3, !4, !5}
 !llvm.ident = !{!6}
@@ -59,6 +87,21 @@ return:
 !19 = distinct !{!19, !16, !20}
 !20 = !{!"llvm.loop.unroll.enable"}
 !21 = !DILocation(line: 12, column: 1, scope: !15)
+!22 = distinct !DISubprogram(name: "test3", scope: !1, file: !1, line: 8, type: !8, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
+!23 = !DILocation(line: 8, column: 14, scope: !22)
+!24 = !DILocation(line: 11, column: 5, scope: !22)
+!25 = !DILocation(line: 10, column: 3, scope: !22)
+!26 = distinct !{!26, !23, !29, !27}
+!27 = !{!"llvm.loop.unroll.enable"}
+!28 = !DILocation(line: 12, column: 1, scope: !22)
+!29 = !DILocation(line: 12, column: 1, scope: !22)
+!30 = distinct !DISubprogram(name: "test4", scope: !1, file: !1, line: 8, type: !8, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
+!31 = !DILocation(line: 8, column: 14, scope: !30)
+!32 = !DILocation(line: 11, column: 5, scope: !30)
+!33 = !DILocation(line: 10, column: 3, scope: !30)
+!34 = distinct !{!34, !31, !35}
+!35 = !DILocation(line: 12, column: 1, scope: !30)
+!36 = !DILocation(line: 12, column: 1, scope: !30)
 
 ; CHECK-NOT: !DICompileUnit
 ; CHECK-NOT: !DIFile
@@ -68,4 +111,5 @@ return:
 ; CHECK-NOT: !DILexicalBlockFile
 ; CHECK: [[LOOP]] = distinct !{[[LOOP]], [[LOOP_UNROLL:![0-9]+]]}
 ; CHECK-NEXT: [[LOOP_UNROLL]] = !{!"llvm.loop.unroll.enable"}
+; CHECK: [[LOOP2]] = distinct !{[[LOOP2]], [[LOOP_UNROLL]]}
 ; CHECK-NOT: !DILocation