[llvm] c10cc4e - [AMDGPU] Fix computing live registers in prolog

Sebastian Neubauer via llvm-commits llvm-commits at lists.llvm.org
Thu Apr 8 06:04:24 PDT 2021 

Author: Sebastian Neubauer
Date: 2021-04-08T14:52:50+02:00
New Revision: c10cc4ea2729b687757b5932cb568ee6225f6f33

URL: https://github.com/llvm/llvm-project/commit/c10cc4ea2729b687757b5932cb568ee6225f6f33
DIFF: https://github.com/llvm/llvm-project/commit/c10cc4ea2729b687757b5932cb568ee6225f6f33.diff

LOG: [AMDGPU] Fix computing live registers in prolog

ScratchExecCopy needs to be marked as live, we cannot use that register
while EXEC is stored in there.

Marking SGPRForFPSaveRestoreCopy and SGPRForBPSaveRestoreCopy as
available is unnecessary, they should not be live at that point anway.

Differential Revision: https://reviews.llvm.org/D100098

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/SIFrameLowering.cpp
    llvm/test/CodeGen/AMDGPU/pei-scavenge-vgpr-spill.mir

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp b/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp
index dd7d1f3c3c18e..88cb6757822b4 100644
--- a/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp
@@ -803,18 +803,12 @@ static Register buildScratchExecCopy(LivePhysRegs &LiveRegs,
   const GCNSubtarget &ST = MF.getSubtarget<GCNSubtarget>();
   const SIInstrInfo *TII = ST.getInstrInfo();
   const SIRegisterInfo &TRI = TII->getRegisterInfo();
-  SIMachineFunctionInfo *FuncInfo = MF.getInfo<SIMachineFunctionInfo>();
   DebugLoc DL;
 
   if (LiveRegs.empty()) {
     if (IsProlog) {
       LiveRegs.init(TRI);
       LiveRegs.addLiveIns(MBB);
-      if (FuncInfo->SGPRForFPSaveRestoreCopy)
-        LiveRegs.removeReg(FuncInfo->SGPRForFPSaveRestoreCopy);
-
-      if (FuncInfo->SGPRForBPSaveRestoreCopy)
-        LiveRegs.removeReg(FuncInfo->SGPRForBPSaveRestoreCopy);
     } else {
       // In epilog.
       LiveRegs.init(*ST.getRegisterInfo());
@@ -828,8 +822,7 @@ static Register buildScratchExecCopy(LivePhysRegs &LiveRegs,
   if (!ScratchExecCopy)
     report_fatal_error("failed to find free scratch register");
 
-  if (!IsProlog)
-    LiveRegs.removeReg(ScratchExecCopy);
+  LiveRegs.addReg(ScratchExecCopy);
 
   const unsigned OrSaveExec =
       ST.isWave32() ? AMDGPU::S_OR_SAVEEXEC_B32 : AMDGPU::S_OR_SAVEEXEC_B64;

diff  --git a/llvm/test/CodeGen/AMDGPU/pei-scavenge-vgpr-spill.mir b/llvm/test/CodeGen/AMDGPU/pei-scavenge-vgpr-spill.mir
index 08c9d80ba42eb..a6f358afacc6e 100644
--- a/llvm/test/CodeGen/AMDGPU/pei-scavenge-vgpr-spill.mir
+++ b/llvm/test/CodeGen/AMDGPU/pei-scavenge-vgpr-spill.mir
@@ -79,8 +79,8 @@ body:             |
     ; GFX9-FLATSCR-LABEL: name: pei_scavenge_vgpr_spill
     ; GFX9-FLATSCR: liveins: $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10_vgpr11_vgpr12_vgpr13_vgpr14_vgpr15, $vgpr16_vgpr17_vgpr18_vgpr19_vgpr20_vgpr21_vgpr22_vgpr23_vgpr24_vgpr25_vgpr26_vgpr27_vgpr28_vgpr29_vgpr30_vgpr31, $vgpr32_vgpr33_vgpr34_vgpr35_vgpr36_vgpr37_vgpr38_vgpr39_vgpr40_vgpr41_vgpr42_vgpr43_vgpr44_vgpr45_vgpr46_vgpr47, $vgpr48_vgpr49_vgpr50_vgpr51_vgpr52_vgpr53_vgpr54_vgpr55_vgpr56_vgpr57_vgpr58_vgpr59_vgpr60_vgpr61_vgpr62_vgpr63, $vgpr64_vgpr65_vgpr66_vgpr67_vgpr68_vgpr69_vgpr70_vgpr71_vgpr72_vgpr73_vgpr74_vgpr75_vgpr76_vgpr77_vgpr78_vgpr79, $vgpr80_vgpr81_vgpr82_vgpr83_vgpr84_vgpr85_vgpr86_vgpr87_vgpr88_vgpr89_vgpr90_vgpr91_vgpr92_vgpr93_vgpr94_vgpr95, $vgpr96_vgpr97_vgpr98_vgpr99_vgpr100_vgpr101_vgpr102_vgpr103_vgpr104_vgpr105_vgpr106_vgpr107_vgpr108_vgpr109_vgpr110_vgpr111, $vgpr112_vgpr113_vgpr114_vgpr115_vgpr116_vgpr117_vgpr118_vgpr119_vgpr120_vgpr121_vgpr122_vgpr123_vgpr124_vgpr125_vgpr126_vgpr127, $vgpr128_vgpr129_vgpr130_vgpr131_vgpr132_vgpr133_vgpr134_vgpr135_vgpr136_vgpr137_vgpr138_vgpr139_vgpr140_vgpr141_vgpr142_vgpr143, $vgpr144_vgpr145_vgpr146_vgpr147_vgpr148_vgpr149_vgpr150_vgpr151_vgpr152_vgpr153_vgpr154_vgpr155_vgpr156_vgpr157_vgpr158_vgpr159, $vgpr160_vgpr161_vgpr162_vgpr163_vgpr164_vgpr165_vgpr166_vgpr167_vgpr168_vgpr169_vgpr170_vgpr171_vgpr172_vgpr173_vgpr174_vgpr175, $vgpr176_vgpr177_vgpr178_vgpr179_vgpr180_vgpr181_vgpr182_vgpr183_vgpr184_vgpr185_vgpr186_vgpr187_vgpr188_vgpr189_vgpr190_vgpr191, $vgpr192_vgpr193_vgpr194_vgpr195_vgpr196_vgpr197_vgpr198_vgpr199_vgpr200_vgpr201_vgpr202_vgpr203_vgpr204_vgpr205_vgpr206_vgpr207, $vgpr208_vgpr209_vgpr210_vgpr211_vgpr212_vgpr213_vgpr214_vgpr215_vgpr216_vgpr217_vgpr218_vgpr219_vgpr220_vgpr221_vgpr222_vgpr223, $vgpr224_vgpr225_vgpr226_vgpr227_vgpr228_vgpr229_vgpr230_vgpr231_vgpr232_vgpr233_vgpr234_vgpr235_vgpr236_vgpr237_vgpr238_vgpr239, $vgpr240_vgpr241_vgpr242_vgpr243_vgpr244_vgpr245_vgpr246_vgpr247, $vgpr248_vgpr249_vgpr250_vgpr251, $vgpr252_vgpr253_vgpr254_vgpr255, $vgpr2
     ; GFX9-FLATSCR: $sgpr4_sgpr5 = S_OR_SAVEEXEC_B64 -1, implicit-def $exec, implicit-def $scc, implicit $exec
-    ; GFX9-FLATSCR: $sgpr4 = S_ADD_U32 $sgpr32, 8196, implicit-def $scc
-    ; GFX9-FLATSCR: SCRATCH_STORE_DWORD_SADDR killed $vgpr2, killed $sgpr4, 0, 0, implicit $exec, implicit $flat_scr :: (store 4 into %stack.3, addrspace 5)
+    ; GFX9-FLATSCR: $sgpr6 = S_ADD_U32 $sgpr32, 8196, implicit-def $scc
+    ; GFX9-FLATSCR: SCRATCH_STORE_DWORD_SADDR killed $vgpr2, killed $sgpr6, 0, 0, implicit $exec, implicit $flat_scr :: (store 4 into %stack.3, addrspace 5)
     ; GFX9-FLATSCR: $exec = S_MOV_B64 killed $sgpr4_sgpr5
     ; GFX9-FLATSCR: $vgpr2 = V_WRITELANE_B32 $sgpr33, 0, undef $vgpr2
     ; GFX9-FLATSCR: $sgpr33 = frame-setup S_ADD_U32 $sgpr32, 8191, implicit-def $scc
@@ -92,8 +92,8 @@ body:             |
     ; GFX9-FLATSCR: $sgpr32 = frame-destroy S_SUB_U32 $sgpr32, 24576, implicit-def $scc
     ; GFX9-FLATSCR: $sgpr33 = V_READLANE_B32 $vgpr2, 0
     ; GFX9-FLATSCR: $sgpr4_sgpr5 = S_OR_SAVEEXEC_B64 -1, implicit-def $exec, implicit-def $scc, implicit $exec
-    ; GFX9-FLATSCR: $sgpr4 = S_ADD_U32 $sgpr32, 8196, implicit-def $scc
-    ; GFX9-FLATSCR: $vgpr2 = SCRATCH_LOAD_DWORD_SADDR killed $sgpr4, 0, 0, implicit $exec, implicit $flat_scr :: (load 4 from %stack.3, addrspace 5)
+    ; GFX9-FLATSCR: $sgpr6 = S_ADD_U32 $sgpr32, 8196, implicit-def $scc
+    ; GFX9-FLATSCR: $vgpr2 = SCRATCH_LOAD_DWORD_SADDR killed $sgpr6, 0, 0, implicit $exec, implicit $flat_scr :: (load 4 from %stack.3, addrspace 5)
     ; GFX9-FLATSCR: $exec = S_MOV_B64 killed $sgpr4_sgpr5
     ; GFX9-FLATSCR: S_ENDPGM 0, csr_amdgpu_allvgprs
     $vgpr0 = V_MOV_B32_e32 %stack.0, implicit $exec

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