Silence illegal address computation warning

[MartinWehking]

Add an assertion before an access of ValMappings to ensure that it is within the array bounds.
Silence a static analyzer warning through this.

[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

Author: Martin Wehking (MartinWehking)

Changes

Add an assertion before an access of ValMappings to ensure that it is within the array bounds.
Silence a static analyzer warning through this.

---

Full diff: https://github.com/llvm/llvm-project/pull/83244.diff

1 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/AMDGPUGenRegisterBankInfo.def (+1)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUGenRegisterBankInfo.def b/llvm/lib/Target/AMDGPU/AMDGPUGenRegisterBankInfo.def
index d6a94c972340ea..e7b3afc91d6520 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUGenRegisterBankInfo.def
+++ b/llvm/lib/Target/AMDGPU/AMDGPUGenRegisterBankInfo.def
@@ -284,6 +284,7 @@ const RegisterBankInfo::ValueMapping *getValueMapping(unsigned BankID,
     break;
   }
 
+  assert(Idx < sizeof(ValMappings) / sizeof(ValMappings[0]));
   assert(Log2_32_Ceil(Size) == Log2_32_Ceil(ValMappings[Idx].BreakDown->Length));
   assert(BankID == ValMappings[Idx].BreakDown->RegBank->getID());