[PrologEpilogInserter][AMDGPU] Only adjust offset for emergency spill slots if the stack grows down

[rogfer01]

Summary

D89239 adjusts the stack offset of emergency spill slots for overaligned stacks. However the adjustment is not valid for targets whose stack grows up (such as a AMDGPU).

This change makes the adjustment conditional only to those targets whose stack grows down.

Fixes https://bugs.llvm.org/show_bug.cgi?id=49686

[sebastian-ne]

Thank you

llvm/lib/CodeGen/PrologEpilogInserter.cpp

if (!TFI.targetHandlesStackFrameRounding()) {
     // SP not FP. Align to MaxAlign so this works.
     StackAlign = std::max(StackAlign, MaxAlign);
     int64_t OffsetBeforeAlignment = Offset;
     Offset = alignTo(Offset, StackAlign, Skew);
 
     // If we have increased the offset to fulfill the alignment constrants,
     // then the scavenging spill slots may become harder to reach from the
     // stack pointer, float them so they stay close.
-    if (OffsetBeforeAlignment != Offset && RS && !EarlyScavengingSlots) {
+    if (StackGrowsDown && OffsetBeforeAlignment != Offset && RS &&
+        !EarlyScavengingSlots) {
       SmallVector<int, 2> SFIs;
       RS->getScavengingFrameIndices(SFIs);
       LLVM_DEBUG(if (!SFIs.empty()) llvm::dbgs()
                      << "Adjusting emergency spill slots!\n";);
       int64_t Delta = Offset - OffsetBeforeAlignment;
       for (int SFI : SFIs) {
         LLVM_DEBUG(llvm::dbgs()
                        << "Adjusting offset of emergency spill slot #" << SFI

llvm/test/CodeGen/AMDGPU/pei-scavenge-vgpr-spill.mir

bb.0:
     ; GFX8: BUFFER_STORE_DWORD_OFFSET killed $vgpr2, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr32, 0, 0, 0, 0, implicit $exec :: (store 4 into %stack.3, addrspace 5)
     ; GFX8: $sgpr32 = S_SUB_U32 $sgpr32, 8196, implicit-def $scc
     ; GFX8: $exec = S_MOV_B64 killed $sgpr4_sgpr5
     ; GFX8: $vgpr2 = V_WRITELANE_B32 $sgpr33, 0, undef $vgpr2
     ; GFX8: $sgpr33 = frame-setup S_ADD_U32 $sgpr32, 524224, implicit-def $scc
     ; GFX8: $sgpr33 = frame-setup S_AND_B32 killed $sgpr33, 4294443008, implicit-def $scc
     ; GFX8: $sgpr32 = frame-setup S_ADD_U32 $sgpr32, 1572864, implicit-def $scc
     ; GFX8: $vgpr0 = V_LSHRREV_B32_e64 6, $sgpr33, implicit $exec
-    ; GFX8: BUFFER_STORE_DWORD_OFFSET killed $vgpr3, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr33, 20, 0, 0, 0, implicit $exec :: (store 4 into %stack.4, addrspace 5)
+    ; GFX8: $sgpr6 = S_ADD_U32 $sgpr33, 524800, implicit-def $scc
+    ; GFX8: BUFFER_STORE_DWORD_OFFSET killed $vgpr3, $sgpr0_sgpr1_sgpr2_sgpr3, killed $sgpr6, 0, 0, 0, 0, implicit $exec :: (store 4 into %stack.4, addrspace 5)
     ; GFX8: $vgpr3 = V_LSHRREV_B32_e64 6, $sgpr33, implicit $exec
     ; GFX8: $vcc_lo = S_MOV_B32 8192
     ; GFX8: $vgpr3, dead $vcc = V_ADD_CO_U32_e64 killed $vcc_lo, killed $vgpr3, 0, implicit $exec
     ; GFX8: $vgpr0 = V_OR_B32_e32 killed $vgpr3, $vgpr1, implicit $exec
     ; GFX8: $sgpr32 = frame-destroy S_SUB_U32 $sgpr32, 1572864, implicit-def $scc
     ; GFX8: $sgpr33 = V_READLANE_B32 $vgpr2, 0
     ; GFX8: $sgpr4_sgpr5 = S_OR_SAVEEXEC_B64 -1, implicit-def $exec, implicit-def $scc, implicit $exec
     ; GFX8: $vgpr0 = V_MOV_B32_e32 8196, implicit $exec
     ; GFX8: $vgpr2 = BUFFER_LOAD_DWORD_OFFEN killed $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr32, 0, 0, 0, 0, implicit $exec :: (load 4 from %stack.3, addrspace 5)
     ; GFX8: $exec = S_MOV_B64 killed $sgpr4_sgpr5
-    ; GFX8: $vgpr3 = BUFFER_LOAD_DWORD_OFFSET $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr33, 20, 0, 0, 0, implicit $exec :: (load 4 from %stack.4, addrspace 5)
+    ; GFX8: $sgpr4 = S_ADD_U32 $sgpr33, 524800, implicit-def $scc
+    ; GFX8: $vgpr3 = BUFFER_LOAD_DWORD_OFFSET $sgpr0_sgpr1_sgpr2_sgpr3, killed $sgpr4, 0, 0, 0, 0, implicit $exec :: (load 4 from %stack.4, addrspace 5)
     ; GFX8: S_ENDPGM 0, csr_amdgpu_allvgprs
     ; GFX9-LABEL: name: pei_scavenge_vgpr_spill
     ; GFX9: 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: $sgpr4_sgpr5 = S_OR_SAVEEXEC_B64 -1, implicit-def $exec, implicit-def $scc, implicit $exec
     ; GFX9: $sgpr32 = S_ADD_U32 $sgpr32, 8196, implicit-def $scc
     ; GFX9: BUFFER_STORE_DWORD_OFFSET killed $vgpr2, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr32, 0, 0, 0, 0, implicit $exec :: (store 4 into %stack.3, addrspace 5)
     ; GFX9: $sgpr32 = S_SUB_U32 $sgpr32, 8196, implicit-def $scc
     ; GFX9: $exec = S_MOV_B64 killed $sgpr4_sgpr5
     ; GFX9: $vgpr2 = V_WRITELANE_B32 $sgpr33, 0, undef $vgpr2
     ; GFX9: $sgpr33 = frame-setup S_ADD_U32 $sgpr32, 524224, implicit-def $scc
     ; GFX9: $sgpr33 = frame-setup S_AND_B32 killed $sgpr33, 4294443008, implicit-def $scc
     ; GFX9: $sgpr32 = frame-setup S_ADD_U32 $sgpr32, 1572864, implicit-def $scc
     ; GFX9: $vgpr0 = V_LSHRREV_B32_e64 6, $sgpr33, implicit $exec
-    ; GFX9: BUFFER_STORE_DWORD_OFFSET killed $vgpr3, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr33, 20, 0, 0, 0, implicit $exec :: (store 4 into %stack.4, addrspace 5)
+    ; GFX9: $sgpr6 = S_ADD_U32 $sgpr33, 524800, implicit-def $scc
+    ; GFX9: BUFFER_STORE_DWORD_OFFSET killed $vgpr3, $sgpr0_sgpr1_sgpr2_sgpr3, killed $sgpr6, 0, 0, 0, 0, implicit $exec :: (store 4 into %stack.4, addrspace 5)
     ; GFX9: $vgpr3 = V_LSHRREV_B32_e64 6, $sgpr33, implicit $exec
     ; GFX9: $vgpr3 = V_ADD_U32_e32 8192, killed $vgpr3, implicit $exec
     ; GFX9: $vgpr0 = V_OR_B32_e32 killed $vgpr3, $vgpr1, implicit $exec
     ; GFX9: $sgpr32 = frame-destroy S_SUB_U32 $sgpr32, 1572864, implicit-def $scc
     ; GFX9: $sgpr33 = V_READLANE_B32 $vgpr2, 0
     ; GFX9: $sgpr4_sgpr5 = S_OR_SAVEEXEC_B64 -1, implicit-def $exec, implicit-def $scc, implicit $exec
     ; GFX9: $vgpr0 = V_MOV_B32_e32 8196, implicit $exec
     ; GFX9: $vgpr2 = BUFFER_LOAD_DWORD_OFFEN killed $vgpr0, $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr32, 0, 0, 0, 0, implicit $exec :: (load 4 from %stack.3, addrspace 5)
     ; GFX9: $exec = S_MOV_B64 killed $sgpr4_sgpr5
-    ; GFX9: $vgpr3 = BUFFER_LOAD_DWORD_OFFSET $sgpr0_sgpr1_sgpr2_sgpr3, $sgpr33, 20, 0, 0, 0, implicit $exec :: (load 4 from %stack.4, addrspace 5)
+    ; GFX9: $sgpr4 = S_ADD_U32 $sgpr33, 524800, implicit-def $scc
+    ; GFX9: $vgpr3 = BUFFER_LOAD_DWORD_OFFSET $sgpr0_sgpr1_sgpr2_sgpr3, killed $sgpr4, 0, 0, 0, 0, implicit $exec :: (load 4 from %stack.4, addrspace 5)
     ; GFX9: S_ENDPGM 0, csr_amdgpu_allvgprs
     ; 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: $exec = S_MOV_B64 killed $sgpr4_sgpr5
     ; GFX9-FLATSCR: $vgpr2 = V_WRITELANE_B32 $sgpr33, 0, undef $vgpr2