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

[via llvm-commits]

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

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.

>From a7381153de6d79e2d45f277fa0ea60898a9eb053 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/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 eab2acd6cb1e7e..2c41c59e977abe 100644
--- a/llvm/test/TableGen/GlobalISelEmitter.td
+++ b/llvm/test/TableGen/GlobalISelEmitter.td
@@ -109,7 +109,7 @@ 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())
@@ -119,7 +119,7 @@ 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/SubtargetFeatureInfo.cpp b/llvm/utils/TableGen/SubtargetFeatureInfo.cpp
index 52afb4d8916279..a0c01577144650 100644
--- a/llvm/utils/TableGen/SubtargetFeatureInfo.cpp
+++ b/llvm/utils/TableGen/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");