AMDGPU: Diagnose using too many SGPRs

[arsenm]

Summary

This is possible when using inline asm.

[• tstellarAMD]

LGTM.

[Eugene.Zelenko]

Looks like patch was not committed.

[arsenm]

r285447

lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp

ProgInfo.DebuggerPrivateSegmentBufferSGPR =
       RI->getHWRegIndex(MFI->getScratchRSrcReg());
   }
 
   // We found the maximum register index. They start at 0, so add one to get the
   // number of registers.
   ProgInfo.NumVGPR = MaxVGPR + 1;
   ProgInfo.NumSGPR = MaxSGPR + 1;
 
-  if (STM.hasSGPRInitBug()) {
-    if (ProgInfo.NumSGPR > SISubtarget::FIXED_SGPR_COUNT_FOR_INIT_BUG) {
-      LLVMContext &Ctx = MF.getFunction()->getContext();
-      DiagnosticInfoResourceLimit Diag(*MF.getFunction(),
-                                       "SGPRs with SGPR init bug",
-                                       ProgInfo.NumSGPR, DS_Error);
-      Ctx.diagnose(Diag);
-    }
-
-    ProgInfo.NumSGPR = SISubtarget::FIXED_SGPR_COUNT_FOR_INIT_BUG;
+  unsigned MaxNumSGPRs = STM.getMaxNumSGPRs();
+  if (ProgInfo.NumSGPR > MaxNumSGPRs) {
+    // This can happen due to a compiler bug or when using inline asm to use the
+    // registers which are usually reserved for vcc etc.
+
+                                     "scalar registers",
+                                     ProgInfo.NumSGPR, DS_Error,
+                                     DK_ResourceLimit, MaxNumSGPRs);
+    ProgInfo.NumSGPR = MaxNumSGPRs;
   }
 
   if (MFI->NumUserSGPRs > STM.getMaxNumUserSGPRs()) {
     LLVMContext &Ctx = MF.getFunction()->getContext();
     DiagnosticInfoResourceLimit Diag(*MF.getFunction(), "user SGPRs",
                                      MFI->NumUserSGPRs, DS_Error);
     Ctx.diagnose(Diag);
   }

lib/Target/AMDGPU/AMDGPUSubtarget.h

public:
 
   bool loadStoreOptEnabled() const {
     return EnableLoadStoreOpt;
   }
 
   bool hasSGPRInitBug() const {
     return SGPRInitBug;
   }
+
+  unsigned getMaxNumSGPRs() const;
 };
 
 } // End namespace llvm
 
 #endif

lib/Target/AMDGPU/AMDGPUSubtarget.cpp

void SISubtarget::overrideSchedPolicy(MachineSchedPolicy &Policy,
   // Enabling ShouldTrackLaneMasks crashes the SI Machine Scheduler.
   if (!enableSIScheduler())
     Policy.ShouldTrackLaneMasks = true;
 }
 
 bool SISubtarget::isVGPRSpillingEnabled(const Function& F) const {
   return EnableVGPRSpilling || !AMDGPU::isShader(F.getCallingConv());
 }
+
+unsigned SISubtarget::getMaxNumSGPRs() const {
+  if (hasSGPRInitBug())
+    return SISubtarget::FIXED_SGPR_COUNT_FOR_INIT_BUG;
+
+  if (getGeneration() >= VOLCANIC_ISLANDS)
+    return 102;
+
+  return 104;
+}

test/CodeGen/AMDGPU/exceed-max-sgprs.ll

+; RUN: not llc -march=amdgcn -verify-machineinstrs < %s 2>&1 | FileCheck -check-prefix=ERROR %s
+
+
+
+; ERROR: error: scalar registers limit of 104 exceeded (106) in use_too_many_sgprs_tahiti
+define void @use_too_many_sgprs_tahiti() #0 {
+  call void asm sideeffect "", "~{SGPR0_SGPR1_SGPR2_SGPR3_SGPR4_SGPR5_SGPR6_SGPR7}" ()
+  call void asm sideeffect "", "~{SGPR8_SGPR9_SGPR10_SGPR11_SGPR12_SGPR13_SGPR14_SGPR15}" ()
+  call void asm sideeffect "", "~{SGPR16_SGPR17_SGPR18_SGPR19_SGPR20_SGPR21_SGPR22_SGPR23}" ()
+  call void asm sideeffect "", "~{SGPR24_SGPR25_SGPR26_SGPR27_SGPR28_SGPR29_SGPR30_SGPR31}" ()
+  call void asm sideeffect "", "~{SGPR32_SGPR33_SGPR34_SGPR35_SGPR36_SGPR37_SGPR38_SGPR39}" ()
+  call void asm sideeffect "", "~{SGPR40_SGPR41_SGPR42_SGPR43_SGPR44_SGPR45_SGPR46_SGPR47}" ()
+  call void asm sideeffect "", "~{SGPR48_SGPR49_SGPR50_SGPR51_SGPR52_SGPR53_SGPR54_SGPR55}" ()
+  call void asm sideeffect "", "~{SGPR56_SGPR57_SGPR58_SGPR59_SGPR60_SGPR61_SGPR62_SGPR63}" ()
+  call void asm sideeffect "", "~{SGPR64_SGPR65_SGPR66_SGPR67_SGPR68_SGPR69_SGPR70_SGPR71}" ()
+  call void asm sideeffect "", "~{SGPR72_SGPR73_SGPR74_SGPR75_SGPR76_SGPR77_SGPR78_SGPR79}" ()
+  call void asm sideeffect "", "~{SGPR80_SGPR81_SGPR82_SGPR83_SGPR84_SGPR85_SGPR86_SGPR87}" ()
+  call void asm sideeffect "", "~{SGPR88_SGPR89_SGPR90_SGPR91_SGPR92_SGPR93_SGPR94_SGPR95}" ()
+  call void asm sideeffect "", "~{SGPR96_SGPR97_SGPR98_SGPR99_SGPR100_SGPR101_SGPR102_SGPR103}" ()
+  call void asm sideeffect "", "~{VCC}" ()
+  ret void
+}
+
+; ERROR: error: scalar registers limit of 104 exceeded (106) in use_too_many_sgprs_bonaire
+define void @use_too_many_sgprs_bonaire() #1 {
+  call void asm sideeffect "", "~{SGPR0_SGPR1_SGPR2_SGPR3_SGPR4_SGPR5_SGPR6_SGPR7}" ()
+  call void asm sideeffect "", "~{SGPR8_SGPR9_SGPR10_SGPR11_SGPR12_SGPR13_SGPR14_SGPR15}" ()
+  call void asm sideeffect "", "~{SGPR16_SGPR17_SGPR18_SGPR19_SGPR20_SGPR21_SGPR22_SGPR23}" ()
+  call void asm sideeffect "", "~{SGPR24_SGPR25_SGPR26_SGPR27_SGPR28_SGPR29_SGPR30_SGPR31}" ()
+  call void asm sideeffect "", "~{SGPR32_SGPR33_SGPR34_SGPR35_SGPR36_SGPR37_SGPR38_SGPR39}" ()
+  call void asm sideeffect "", "~{SGPR40_SGPR41_SGPR42_SGPR43_SGPR44_SGPR45_SGPR46_SGPR47}" ()
+  call void asm sideeffect "", "~{SGPR48_SGPR49_SGPR50_SGPR51_SGPR52_SGPR53_SGPR54_SGPR55}" ()
+  call void asm sideeffect "", "~{SGPR56_SGPR57_SGPR58_SGPR59_SGPR60_SGPR61_SGPR62_SGPR63}" ()
+  call void asm sideeffect "", "~{SGPR64_SGPR65_SGPR66_SGPR67_SGPR68_SGPR69_SGPR70_SGPR71}" ()
+  call void asm sideeffect "", "~{SGPR72_SGPR73_SGPR74_SGPR75_SGPR76_SGPR77_SGPR78_SGPR79}" ()
+  call void asm sideeffect "", "~{SGPR80_SGPR81_SGPR82_SGPR83_SGPR84_SGPR85_SGPR86_SGPR87}" ()
+  call void asm sideeffect "", "~{SGPR88_SGPR89_SGPR90_SGPR91_SGPR92_SGPR93_SGPR94_SGPR95}" ()
+  call void asm sideeffect "", "~{SGPR96_SGPR97_SGPR98_SGPR99_SGPR100_SGPR101_SGPR102_SGPR103}" ()
+  call void asm sideeffect "", "~{VCC}" ()
+  ret void
+}
+
+; ERROR: error: scalar registers limit of 104 exceeded (108) in use_too_many_sgprs_bonaire_flat_scr
+define void @use_too_many_sgprs_bonaire_flat_scr() #1 {
+  call void asm sideeffect "", "~{SGPR0_SGPR1_SGPR2_SGPR3_SGPR4_SGPR5_SGPR6_SGPR7}" ()
+  call void asm sideeffect "", "~{SGPR8_SGPR9_SGPR10_SGPR11_SGPR12_SGPR13_SGPR14_SGPR15}" ()
+  call void asm sideeffect "", "~{SGPR16_SGPR17_SGPR18_SGPR19_SGPR20_SGPR21_SGPR22_SGPR23}" ()
+  call void asm sideeffect "", "~{SGPR24_SGPR25_SGPR26_SGPR27_SGPR28_SGPR29_SGPR30_SGPR31}" ()
+  call void asm sideeffect "", "~{SGPR32_SGPR33_SGPR34_SGPR35_SGPR36_SGPR37_SGPR38_SGPR39}" ()
+  call void asm sideeffect "", "~{SGPR40_SGPR41_SGPR42_SGPR43_SGPR44_SGPR45_SGPR46_SGPR47}" ()
+  call void asm sideeffect "", "~{SGPR48_SGPR49_SGPR50_SGPR51_SGPR52_SGPR53_SGPR54_SGPR55}" ()
+  call void asm sideeffect "", "~{SGPR56_SGPR57_SGPR58_SGPR59_SGPR60_SGPR61_SGPR62_SGPR63}" ()
+  call void asm sideeffect "", "~{SGPR64_SGPR65_SGPR66_SGPR67_SGPR68_SGPR69_SGPR70_SGPR71}" ()
+  call void asm sideeffect "", "~{SGPR72_SGPR73_SGPR74_SGPR75_SGPR76_SGPR77_SGPR78_SGPR79}" ()
+  call void asm sideeffect "", "~{SGPR80_SGPR81_SGPR82_SGPR83_SGPR84_SGPR85_SGPR86_SGPR87}" ()
+  call void asm sideeffect "", "~{SGPR88_SGPR89_SGPR90_SGPR91_SGPR92_SGPR93_SGPR94_SGPR95}" ()
+  call void asm sideeffect "", "~{SGPR96_SGPR97_SGPR98_SGPR99_SGPR100_SGPR101_SGPR102_SGPR103}" ()
+  call void asm sideeffect "", "~{VCC}" ()
+  call void asm sideeffect "", "~{FLAT_SCR}" ()
+  ret void
+}
+
+; ERROR: error: scalar registers limit of 96 exceeded (98) in use_too_many_sgprs_iceland
+define void @use_too_many_sgprs_iceland() #2 {
+  call void asm sideeffect "", "~{VCC}" ()
+  call void asm sideeffect "", "~{SGPR0_SGPR1_SGPR2_SGPR3_SGPR4_SGPR5_SGPR6_SGPR7}" ()
+  call void asm sideeffect "", "~{SGPR8_SGPR9_SGPR10_SGPR11_SGPR12_SGPR13_SGPR14_SGPR15}" ()
+  call void asm sideeffect "", "~{SGPR16_SGPR17_SGPR18_SGPR19_SGPR20_SGPR21_SGPR22_SGPR23}" ()
+  call void asm sideeffect "", "~{SGPR24_SGPR25_SGPR26_SGPR27_SGPR28_SGPR29_SGPR30_SGPR31}" ()
+  call void asm sideeffect "", "~{SGPR32_SGPR33_SGPR34_SGPR35_SGPR36_SGPR37_SGPR38_SGPR39}" ()
+  call void asm sideeffect "", "~{SGPR40_SGPR41_SGPR42_SGPR43_SGPR44_SGPR45_SGPR46_SGPR47}" ()
+  call void asm sideeffect "", "~{SGPR48_SGPR49_SGPR50_SGPR51_SGPR52_SGPR53_SGPR54_SGPR55}" ()
+  call void asm sideeffect "", "~{SGPR56_SGPR57_SGPR58_SGPR59_SGPR60_SGPR61_SGPR62_SGPR63}" ()
+  call void asm sideeffect "", "~{SGPR64_SGPR65_SGPR66_SGPR67_SGPR68_SGPR69_SGPR70_SGPR71}" ()
+  call void asm sideeffect "", "~{SGPR72_SGPR73_SGPR74_SGPR75_SGPR76_SGPR77_SGPR78_SGPR79}" ()
+  call void asm sideeffect "", "~{SGPR80_SGPR81_SGPR82_SGPR83_SGPR84_SGPR85_SGPR86_SGPR87}" ()
+  call void asm sideeffect "", "~{SGPR88_SGPR89_SGPR90_SGPR91_SGPR92_SGPR93_SGPR94_SGPR95}" ()
+  ret void
+}
+
+; ERROR: error: scalar registers limit of 102 exceeded (103) in use_too_many_sgprs_fiji
+define void @use_too_many_sgprs_fiji() #3 {
+  call void asm sideeffect "", "~{SGPR0_SGPR1_SGPR2_SGPR3_SGPR4_SGPR5_SGPR6_SGPR7}" ()
+  call void asm sideeffect "", "~{SGPR8_SGPR9_SGPR10_SGPR11_SGPR12_SGPR13_SGPR14_SGPR15}" ()
+  call void asm sideeffect "", "~{SGPR16_SGPR17_SGPR18_SGPR19_SGPR20_SGPR21_SGPR22_SGPR23}" ()
+  call void asm sideeffect "", "~{SGPR24_SGPR25_SGPR26_SGPR27_SGPR28_SGPR29_SGPR30_SGPR31}" ()
+  call void asm sideeffect "", "~{SGPR32_SGPR33_SGPR34_SGPR35_SGPR36_SGPR37_SGPR38_SGPR39}" ()
+  call void asm sideeffect "", "~{SGPR40_SGPR41_SGPR42_SGPR43_SGPR44_SGPR45_SGPR46_SGPR47}" ()
+  call void asm sideeffect "", "~{SGPR48_SGPR49_SGPR50_SGPR51_SGPR52_SGPR53_SGPR54_SGPR55}" ()
+  call void asm sideeffect "", "~{SGPR56_SGPR57_SGPR58_SGPR59_SGPR60_SGPR61_SGPR62_SGPR63}" ()
+  call void asm sideeffect "", "~{SGPR64_SGPR65_SGPR66_SGPR67_SGPR68_SGPR69_SGPR70_SGPR71}" ()
+  call void asm sideeffect "", "~{SGPR72_SGPR73_SGPR74_SGPR75_SGPR76_SGPR77_SGPR78_SGPR79}" ()
+  call void asm sideeffect "", "~{SGPR80_SGPR81_SGPR82_SGPR83_SGPR84_SGPR85_SGPR86_SGPR87}" ()
+  call void asm sideeffect "", "~{SGPR88_SGPR89_SGPR90_SGPR91_SGPR92_SGPR93_SGPR94_SGPR95}" ()
+  call void asm sideeffect "", "~{SGPR96_SGPR97_SGPR98_SGPR99}" ()
+  call void asm sideeffect "", "~{SGPR100_SGPR101}" ()
+  call void asm sideeffect "", "~{SGPR102}" ()
+  ret void
+}
+
+attributes #0 = { nounwind "target-cpu"="tahiti" }
+attributes #1 = { nounwind "target-cpu"="bonaire" }
+attributes #2 = { nounwind "target-cpu"="iceland" }
+attributes #3 = { nounwind "target-cpu"="fiji" }