[llvm] r313875 - [SROA] Really remove associated dbg.declare when removing dead alloca
Mikael Holmen via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 21 04:14:27 PDT 2017
Author: uabelho
Date: Thu Sep 21 04:14:27 2017
New Revision: 313875
URL: http://llvm.org/viewvc/llvm-project?rev=313875&view=rev
Log:
[SROA] Really remove associated dbg.declare when removing dead alloca
Summary:
There already was code that tried to remove the dbg.declare, but that code
was placed after we had called
I->replaceAllUsesWith(UndefValue::get(I->getType()));
on the alloca, so when we searched for the relevant dbg.declare, we
couldn't find it.
Now we do the search before we call RAUW so there is a chance to find it.
An existing testcase needed update due to this. Two dbg.declare with undef
were removed and then suddenly one of the two CHECKS failed.
Before this patch we got
call void @llvm.dbg.declare(metadata i24* undef, metadata !14, metadata !DIExpression(DW_OP_LLVM_fragment, 32, 24)), !dbg !15
call void @llvm.dbg.declare(metadata %struct.prog_src_register* undef, metadata !14, metadata !DIExpression()), !dbg !15
call void @llvm.dbg.value(metadata i32 0, metadata !14, metadata !DIExpression(DW_OP_LLVM_fragment, 0, 32)), !dbg !15
call void @llvm.dbg.value(metadata i32 0, metadata !14, metadata !DIExpression(DW_OP_LLVM_fragment, 32, 24)), !dbg !15
and with it we get
call void @llvm.dbg.value(metadata i32 0, metadata !14, metadata !DIExpression(DW_OP_LLVM_fragment, 0, 32)), !dbg !15
call void @llvm.dbg.value(metadata i32 0, metadata !14, metadata !DIExpression(DW_OP_LLVM_fragment, 32, 24)), !dbg !15
However, the CHECKs in the testcase checked things in a silly order, so
they only passed since they found things in the first dbg.declare. Now
we changed the order of the checks and the test passes.
Reviewers: rnk
Reviewed By: rnk
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D37900
Added:
llvm/trunk/test/DebugInfo/X86/sroasplit-dbg-declare.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/SROA.cpp
llvm/trunk/test/DebugInfo/X86/sroasplit-5.ll
Modified: llvm/trunk/lib/Transforms/Scalar/SROA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SROA.cpp?rev=313875&r1=313874&r2=313875&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SROA.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SROA.cpp Thu Sep 21 04:14:27 2017
@@ -4247,6 +4247,15 @@ void SROA::deleteDeadInstructions(
Instruction *I = DeadInsts.pop_back_val();
DEBUG(dbgs() << "Deleting dead instruction: " << *I << "\n");
+ // If the instruction is an alloca, find the possible dbg.declare connected
+ // to it, and remove it too. We must do this before calling RAUW or we will
+ // not be able to find it.
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
+ DeletedAllocas.insert(AI);
+ for (DbgInfoIntrinsic *OldDII : FindDbgAddrUses(AI))
+ OldDII->eraseFromParent();
+ }
+
I->replaceAllUsesWith(UndefValue::get(I->getType()));
for (Use &Operand : I->operands())
@@ -4257,12 +4266,6 @@ void SROA::deleteDeadInstructions(
DeadInsts.insert(U);
}
- if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
- DeletedAllocas.insert(AI);
- for (DbgInfoIntrinsic *OldDII : FindDbgAddrUses(AI))
- OldDII->eraseFromParent();
- }
-
++NumDeleted;
I->eraseFromParent();
}
Modified: llvm/trunk/test/DebugInfo/X86/sroasplit-5.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/sroasplit-5.ll?rev=313875&r1=313874&r2=313875&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/sroasplit-5.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/sroasplit-5.ll Thu Sep 21 04:14:27 2017
@@ -20,10 +20,10 @@ target triple = "x86_64-unknown-linux-gn
;
; There should be no debug info for the padding.
; CHECK-NOT: DW_OP_LLVM_fragment, 56
-; CHECK: DIExpression(DW_OP_LLVM_fragment, 32, 24)
-; CHECK-NOT: DW_OP_LLVM_fragment, 56
; CHECK: DIExpression(DW_OP_LLVM_fragment, 0, 32)
; CHECK-NOT: DW_OP_LLVM_fragment, 56
+; CHECK: DIExpression(DW_OP_LLVM_fragment, 32, 24)
+; CHECK-NOT: DW_OP_LLVM_fragment, 56
%struct.prog_src_register = type { i32, i24 }
; Function Attrs: nounwind
Added: llvm/trunk/test/DebugInfo/X86/sroasplit-dbg-declare.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/sroasplit-dbg-declare.ll?rev=313875&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/sroasplit-dbg-declare.ll (added)
+++ llvm/trunk/test/DebugInfo/X86/sroasplit-dbg-declare.ll Thu Sep 21 04:14:27 2017
@@ -0,0 +1,59 @@
+; RUN: opt -S -sroa -o - %s | FileCheck %s
+
+; SROA should split the alloca in two new ones, each with its own dbg.declare.
+; The original alloca and dbg.declare should be removed.
+
+define void @f1() {
+entry:
+ %0 = alloca [9 x i32]
+ call void @llvm.dbg.declare(metadata [9 x i32]* %0, metadata !11, metadata !DIExpression()), !dbg !17
+ %1 = bitcast [9 x i32]* %0 to i8*
+ call void @llvm.memset.p0i8.i64(i8* %1, i8 0, i64 36, i32 16, i1 true)
+ %2 = getelementptr [9 x i32], [9 x i32]* %0, i32 0, i32 0
+ store volatile i32 1, i32* %2
+ ret void
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i32, i1) #0
+
+attributes #0 = { argmemonly nounwind }
+attributes #1 = { nounwind readnone speculatable }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "foo.c", directory: "/bar")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 6.0.0"}
+!7 = distinct !DISubprogram(name: "f1", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !10)
+!8 = !DISubroutineType(types: !9)
+!9 = !{null}
+!10 = !{!11}
+!11 = !DILocalVariable(name: "b", scope: !7, file: !1, line: 3, type: !12)
+!12 = !DICompositeType(tag: DW_TAG_array_type, baseType: !13, size: 288, elements: !15)
+!13 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !14)
+!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!15 = !{!16}
+!16 = !DISubrange(count: 9)
+!17 = !DILocation(line: 3, column: 18, scope: !7)
+
+; CHECK-NOT: = alloca [9 x i32]
+; CHECK-NOT: call void @llvm.dbg.declare(metadata [9 x i32]*
+
+; CHECK: %[[VAR1:.*]] = alloca i32
+; CHECK-NEXT: %[[VAR2:.*]] = alloca [8 x i32]
+; CHECK-NEXT: call void @llvm.dbg.declare(metadata i32* %[[VAR1]]
+; CHECK-NEXT: call void @llvm.dbg.declare(metadata [8 x i32]* %[[VAR2]]
+
+; CHECK-NOT: = alloca [9 x i32]
+; CHECK-NOT: call void @llvm.dbg.declare(metadata [9 x i32]*
+
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