[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

diff --git a/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp b/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp
index dd7d1f3..88cb675 100644 (file)
--- 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 08c9d80..a6f358a 100644 (file)
--- 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