[PATCH] D107538: [GCov] Emit memset instead of stores in __llvm_gcov_reset

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks updated this revision to Diff 364692.
aeubanks added a comment.

move test function


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D107538/new/

https://reviews.llvm.org/D107538

Files:
  llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
  llvm/test/Transforms/GCOVProfiling/reset.ll


Index: llvm/test/Transforms/GCOVProfiling/reset.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/GCOVProfiling/reset.ll
@@ -0,0 +1,37 @@
+; RUN: mkdir -p %t && cd %t
+; RUN: opt < %s -S -passes=insert-gcov-profiling | FileCheck %s
+
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @foo() !dbg !8 {
+entry:
+  ret void, !dbg !12
+}
+
+define void @bar() !dbg !13 {
+entry:
+  ret void, !dbg !14
+}
+
+; CHECK: define internal void @__llvm_gcov_reset()
+; CHECK-NEXT: entry:
+; CHECK-NEXT: call void @llvm.memset.p0i8.i64(i8* bitcast ([1 x i64]* @__llvm_gcov_ctr to i8*), i8 0, i64 8, i1 false)
+; CHECK-NEXT: call void @llvm.memset.p0i8.i64(i8* bitcast ([1 x i64]* @__llvm_gcov_ctr.1 to i8*), i8 0, i64 8, i1 false)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 14.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "/tmp/a.c", directory: "/tmp")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{i32 7, !"uwtable", i32 1}
+!8 = distinct !DISubprogram(name: "foo", scope: !9, file: !9, line: 1, type: !10, scopeLine: 1, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!9 = !DIFile(filename: "/tmp/a.c", directory: "")
+!10 = !DISubroutineType(types: !11)
+!11 = !{null}
+!12 = !DILocation(line: 1, column: 13, scope: !8)
+!13 = distinct !DISubprogram(name: "bar", scope: !9, file: !9, line: 2, type: !10, scopeLine: 2, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!14 = !DILocation(line: 2, column: 13, scope: !13)
Index: llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ llvm/lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -1373,12 +1373,16 @@
 
   BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", ResetF);
   IRBuilder<> Builder(Entry);
+  LLVMContext &C = Entry->getContext();
 
   // Zero out the counters.
   for (const auto &I : CountersBySP) {
     GlobalVariable *GV = I.first;
-    Constant *Null = Constant::getNullValue(GV->getValueType());
-    Builder.CreateStore(Null, GV);
+    auto *GVTy = cast<ArrayType>(GV->getValueType());
+    Builder.CreateMemSet(GV, Constant::getNullValue(Type::getInt8Ty(C)),
+                         GVTy->getNumElements() *
+                             GVTy->getElementType()->getScalarSizeInBits() / 8,
+                         GV->getAlign());
   }
 
   Type *RetTy = ResetF->getReturnType();


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