[llvm] [TableGen] Make default initialization explicit (PR #75461)

[Martin Wehking via llvm-commits]

https://github.com/MartinWehking updated https://github.com/llvm/llvm-project/pull/75461

>From 9a890976756de9ee5198d4513f639bb9a4dd9d6d Mon Sep 17 00:00:00 2001
From: Martin Wehking <martin.wehking at codeplay.com>
Date: Thu, 14 Dec 2023 05:37:36 -0500
Subject: [PATCH] Make default initialization explicit

Coverity (a static analysis tool) reported that the emitted 'Features'
variable inside emitComputeAvailableFeatures in TableGen might be
unitialized.
Silence this warning by adding brackets for the default initialization.
Adapt test cases to take additional brackets into account.
---
 llvm/test/TableGen/GlobalISelEmitter.td             | 4 ++--
 llvm/test/TableGen/GlobalISelEmitterHwModes.td      | 4 ++--
 llvm/utils/TableGen/Common/SubtargetFeatureInfo.cpp | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/llvm/test/TableGen/GlobalISelEmitter.td b/llvm/test/TableGen/GlobalISelEmitter.td
index 82ecc4495e80ac..961200d9b63542 100644
--- a/llvm/test/TableGen/GlobalISelEmitter.td
+++ b/llvm/test/TableGen/GlobalISelEmitter.td
@@ -110,7 +110,7 @@ def HasC : Predicate<"Subtarget->hasC()"> { let RecomputePerFunction = 1; }
 
 // CHECK-LABEL: PredicateBitset MyTargetInstructionSelector::
 // CHECK-NEXT:  computeAvailableModuleFeatures(const MyTargetSubtarget *Subtarget) const {
-// CHECK-NEXT:    PredicateBitset Features;
+// CHECK-NEXT:    PredicateBitset Features{};
 // CHECK-NEXT:    if (Subtarget->hasA())
 // CHECK-NEXT:      Features.set(Feature_HasABit);
 // CHECK-NEXT:    if (Subtarget->hasB())
@@ -120,7 +120,7 @@ def HasC : Predicate<"Subtarget->hasC()"> { let RecomputePerFunction = 1; }
 
 // CHECK-LABEL: PredicateBitset MyTargetInstructionSelector::
 // CHECK-NEXT:  computeAvailableFunctionFeatures(const MyTargetSubtarget *Subtarget, const MachineFunction *MF) const {
-// CHECK-NEXT:    PredicateBitset Features;
+// CHECK-NEXT:    PredicateBitset Features{};
 // CHECK-NEXT:    if (Subtarget->hasC())
 // CHECK-NEXT:      Features.set(Feature_HasCBit);
 // CHECK-NEXT:    return Features;
diff --git a/llvm/test/TableGen/GlobalISelEmitterHwModes.td b/llvm/test/TableGen/GlobalISelEmitterHwModes.td
index 0c826fb50beb5f..b96e9db0134bfe 100644
--- a/llvm/test/TableGen/GlobalISelEmitterHwModes.td
+++ b/llvm/test/TableGen/GlobalISelEmitterHwModes.td
@@ -85,7 +85,7 @@ class I<dag OOps, dag IOps, list<dag> Pat>
 
 // CHECK-LABEL: PredicateBitset MyTargetInstructionSelector::
 // CHECK-NEXT:  computeAvailableModuleFeatures(const MyTargetSubtarget *Subtarget) const {
-// CHECK-NEXT:    PredicateBitset Features;
+// CHECK-NEXT:    PredicateBitset Features{};
 // CHECK-NEXT:    if (!((Subtarget->has64())))
 // CHECK-NEXT:      Features.set(Feature_HwMode1Bit);
 // CHECK-NEXT:    if ((Subtarget->has64()))
@@ -95,7 +95,7 @@ class I<dag OOps, dag IOps, list<dag> Pat>
 
 // CHECK-LABEL: PredicateBitset MyTargetInstructionSelector::
 // CHECK-NEXT:  computeAvailableFunctionFeatures(const MyTargetSubtarget *Subtarget, const MachineFunction *MF) const {
-// CHECK-NEXT:    PredicateBitset Features;
+// CHECK-NEXT:    PredicateBitset Features{};
 // CHECK-NEXT:    return Features;
 // CHECK-NEXT:  }
 
diff --git a/llvm/utils/TableGen/Common/SubtargetFeatureInfo.cpp b/llvm/utils/TableGen/Common/SubtargetFeatureInfo.cpp
index 819abfa965a58c..4f57234d6fe275 100644
--- a/llvm/utils/TableGen/Common/SubtargetFeatureInfo.cpp
+++ b/llvm/utils/TableGen/Common/SubtargetFeatureInfo.cpp
@@ -108,7 +108,7 @@ void SubtargetFeatureInfo::emitComputeAvailableFeatures(
   if (!ExtraParams.empty())
     OS << ", " << ExtraParams;
   OS << ") const {\n";
-  OS << "  PredicateBitset Features;\n";
+  OS << "  PredicateBitset Features{};\n";
   for (const auto &SF : SubtargetFeatures) {
     const SubtargetFeatureInfo &SFI = SF.second;
     StringRef CondStr = SFI.TheDef->getValueAsString("CondString");