[llvm] [AMDGPU] Remove duplicate SGPR limit diagnostics from getSIProgramInfo (PR #192232)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: StevenYangCC

<details>
<summary>Changes</summary>

Both getSIProgramInfo() and validateMCResourceInfo() checked SGPR register counts against hardware limits and emitted identical DiagnosticInfoResourceLimit errors. When the MCExpr values were resolvable (common for kernels without unresolved callee dependencies), both checks fired, producing duplicate error messages.

Remove the diagnostic emission from getSIProgramInfo() while retaining the clamping logic needed for correct register block encoding. The single authoritative diagnostic is now emitted by validateMCResourceInfo() during doFinalization.

Update exceed-max-sgprs.ll to enforce exactly one diagnostic per violation via --implicit-check-not.

---
Full diff: https://github.com/llvm/llvm-project/pull/192232.diff


2 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp (+6-12) 
- (modified) llvm/test/CodeGen/AMDGPU/exceed-max-sgprs.ll (+1-1) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
index 856b734ec91e5..d16acdb947e01 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
@@ -1048,18 +1048,15 @@ void AMDGPUAsmPrinter::getSIProgramInfo(SIProgramInfo &ProgInfo,
       ProgInfo.VCCUsed, ProgInfo.FlatUsed,
       getTargetStreamer()->getTargetID()->isXnackOnOrAny(), Ctx);
 
-  // Check the addressable register limit before we add ExtraSGPRs.
+  // Clamp the addressable register count before we add ExtraSGPRs.
+  // The diagnostic is emitted by validateMCResourceInfo() during
+  // doFinalization to avoid duplicate error messages.
   if (STM.getGeneration() >= AMDGPUSubtarget::VOLCANIC_ISLANDS &&
       !STM.hasSGPRInitBug()) {
     unsigned MaxAddressableNumSGPRs = STM.getAddressableNumSGPRs();
     uint64_t NumSgpr;
     if (TryGetMCExprValue(ProgInfo.NumSGPR, NumSgpr) &&
         NumSgpr > MaxAddressableNumSGPRs) {
-      // This can happen due to a compiler bug or when using inline asm.
-      LLVMContext &Ctx = MF.getFunction().getContext();
-      Ctx.diagnose(DiagnosticInfoResourceLimit(
-          MF.getFunction(), "addressable scalar registers", NumSgpr,
-          MaxAddressableNumSGPRs, DS_Error, DK_ResourceLimit));
       ProgInfo.NumSGPR = CreateExpr(MaxAddressableNumSGPRs - 1);
     }
   }
@@ -1103,18 +1100,15 @@ void AMDGPUAsmPrinter::getSIProgramInfo(SIProgramInfo &ProgInfo,
                                    MaxWaves, MFI->getDynamicVGPRBlockSize()))},
                               Ctx);
 
+  // Clamp total SGPRs (including ExtraSGPRs) for correct register block
+  // encoding. The diagnostic is emitted by validateMCResourceInfo() during
+  // doFinalization to avoid duplicate error messages.
   if (STM.getGeneration() <= AMDGPUSubtarget::SEA_ISLANDS ||
       STM.hasSGPRInitBug()) {
     unsigned MaxAddressableNumSGPRs = STM.getAddressableNumSGPRs();
     uint64_t NumSgpr;
     if (TryGetMCExprValue(ProgInfo.NumSGPR, NumSgpr) &&
         NumSgpr > MaxAddressableNumSGPRs) {
-      // This can happen due to a compiler bug or when using inline asm to use
-      // the registers which are usually reserved for vcc etc.
-      LLVMContext &Ctx = MF.getFunction().getContext();
-      Ctx.diagnose(DiagnosticInfoResourceLimit(
-          MF.getFunction(), "scalar registers", NumSgpr, MaxAddressableNumSGPRs,
-          DS_Error, DK_ResourceLimit));
       ProgInfo.NumSGPR = CreateExpr(MaxAddressableNumSGPRs);
       ProgInfo.NumSGPRsForWavesPerEU = CreateExpr(MaxAddressableNumSGPRs);
     }
diff --git a/llvm/test/CodeGen/AMDGPU/exceed-max-sgprs.ll b/llvm/test/CodeGen/AMDGPU/exceed-max-sgprs.ll
index f63f2bc3f42df..e80a18ae9289a 100644
--- a/llvm/test/CodeGen/AMDGPU/exceed-max-sgprs.ll
+++ b/llvm/test/CodeGen/AMDGPU/exceed-max-sgprs.ll
@@ -1,4 +1,4 @@
-; RUN: not llc -mtriple=amdgcn < %s 2>&1 | FileCheck -check-prefix=ERROR %s
+; RUN: not llc -mtriple=amdgcn < %s 2>&1 | FileCheck -check-prefix=ERROR --implicit-check-not="exceeds limit" %s
 
 ; ERROR: error: <unknown>:0:0: scalar registers (106) exceeds limit (104) in function 'use_too_many_sgprs_tahiti'
 define amdgpu_kernel void @use_too_many_sgprs_tahiti() #0 {

``````````

</details>


https://github.com/llvm/llvm-project/pull/192232