[AMDGPU] Coverity fixes - check ret val and init class members

[bratpiorka]

Coverity fixes:

• calling getIntrinsicSignature without checking return value (as is done elsewhere 4 out of 5 times) in llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
• non-static class member MaxSGPRs, MaxVGPRs and MaxUnifiedVGPRs is not initialized in this constructor nor in any functions that it calls in llvm/lib/Target/AMDGPU/GCNRegPressure.h

[llvmorg-github-actions]

@llvm/pr-subscribers-backend-amdgpu

Author: Rafał Rudnicki (bratpiorka)

Changes

Coverity fixes

---

Full diff: https://github.com/llvm/llvm-project/pull/198570.diff

2 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp (+3-2)
• (modified) llvm/lib/Target/AMDGPU/GCNRegPressure.h (+1-1)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
index 6bf70686f5569..b2aed7c5d12c3 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
@@ -279,9 +279,10 @@ simplifyAMDGCNImageIntrinsic(const GCNSubtarget *ST,
         // Obtain the original image sample intrinsic's signature
         // and replace its return type with the half-vector for D16 folding
         SmallVector<Type *, 8> SigTys;
-        Intrinsic::getIntrinsicSignature(II.getCalledFunction(), SigTys);
-        SigTys[0] = HalfVecTy;
+        if (!Intrinsic::getIntrinsicSignature(II.getCalledFunction(), SigTys))
+          return std::nullopt;
 
+        SigTys[0] = HalfVecTy;
         Module *M = II.getModule();
         Function *HalfDecl =
             Intrinsic::getOrInsertDeclaration(M, ImageDimIntr->Intr, SigTys);
diff --git a/llvm/lib/Target/AMDGPU/GCNRegPressure.h b/llvm/lib/Target/AMDGPU/GCNRegPressure.h
index c55796c37f287..c53e4a8a6313e 100644
--- a/llvm/lib/Target/AMDGPU/GCNRegPressure.h
+++ b/llvm/lib/Target/AMDGPU/GCNRegPressure.h
@@ -296,7 +296,7 @@ class GCNRPTarget {
 
   GCNRPTarget(const GCNRegPressure &RP, const MachineFunction &MF)
       : MF(MF), UnifiedRF(MF.getSubtarget<GCNSubtarget>().hasGFX90AInsts()),
-        RP(RP) {}
+        RP(RP), MaxSGPRs(0), MaxVGPRs(0), MaxUnifiedVGPRs(0) {}
 };
 
 ///////////////////////////////////////////////////////////////////////////////

[shiltian]

can you be more specific in the title and description?

[bratpiorka]

@shiltian done

[shiltian]

nit: I'd prefer this to be something like:

  /// Target number of SGPRs.
  unsigned MaxSGPRs = 0;
  /// Target number of ArchVGPRs and AGPRs.
  unsigned MaxVGPRs = 0;
  /// Target number of overall VGPRs for subtargets with unified RFs. Always 0
  /// for subtargets with non-unified RFs.
  unsigned MaxUnifiedVGPRs = 0;

[shiltian]

LGTM with a nit

[bratpiorka]

@shiltian ok, done

[bratpiorka]

@shiltian all tests passed - please merge