[AMDGPU] Fix kill flag on overlapping sgpr copy

Same as on vgpr copies, we cannot kill the source register if it
overlaps with the destination register. Otherwise, the kill of the
source register will also count as a kill for the destination register.

Differential Revision: https://reviews.llvm.org/D120042

Author: Flakebi

llvm/lib/Target/AMDGPU/SIInstrInfo.cpp

@@ -930,7 +930,9 @@ void SIInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
       reportIllegalCopy(this, MBB, MI, DL, DestReg, SrcReg, KillSrc);
       return;
     }
-    expandSGPRCopy(*this, MBB, MI, DL, DestReg, SrcReg, KillSrc, RC, Forward);
+    const bool CanKillSuperReg = KillSrc && !RI.regsOverlap(SrcReg, DestReg);
+    expandSGPRCopy(*this, MBB, MI, DL, DestReg, SrcReg, CanKillSuperReg, RC,
+                   Forward);
     return;
   }
 

llvm/test/CodeGen/AMDGPU/copy-overlap-sgpr-kill.mir

@@ -0,0 +1,49 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx906 -verify-machineinstrs -run-pass=postrapseudos -o - %s | FileCheck %s
+
+# Don't set a kill of the super register on the last instruction with
+# an overlapping copy. This would kill part of the values in the
+# result copies.
+
+---
+name: overlapping_copy_kill_undef_reg_after_copy
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $sgpr30_sgpr31, $sgpr4_sgpr5_sgpr6_sgpr7_sgpr8_sgpr9_sgpr10_sgpr11
+
+    ; CHECK-LABEL: name: overlapping_copy_kill_undef_reg_after_copy
+    ; CHECK: liveins: $sgpr30_sgpr31, $sgpr4_sgpr5_sgpr6_sgpr7_sgpr8_sgpr9_sgpr10_sgpr11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: $sgpr0_sgpr1 = S_MOV_B64 $sgpr4_sgpr5, implicit $sgpr4_sgpr5_sgpr6_sgpr7_sgpr8_sgpr9_sgpr10_sgpr11, implicit-def $sgpr0_sgpr1_sgpr2_sgpr3_sgpr4_sgpr5_sgpr6_sgpr7
+    ; CHECK-NEXT: $sgpr2_sgpr3 = S_MOV_B64 $sgpr6_sgpr7, implicit $sgpr4_sgpr5_sgpr6_sgpr7_sgpr8_sgpr9_sgpr10_sgpr11
+    ; CHECK-NEXT: $sgpr4_sgpr5 = S_MOV_B64 $sgpr8_sgpr9, implicit $sgpr4_sgpr5_sgpr6_sgpr7_sgpr8_sgpr9_sgpr10_sgpr11
+    ; CHECK-NEXT: $sgpr6_sgpr7 = S_MOV_B64 $sgpr10_sgpr11, implicit $sgpr4_sgpr5_sgpr6_sgpr7_sgpr8_sgpr9_sgpr10_sgpr11
+    ; CHECK-NEXT: renamable $sgpr1 = S_ADD_I32 0, $sgpr1, implicit-def $scc
+    ; CHECK-NEXT: S_SETPC_B64 $sgpr30_sgpr31, implicit $sgpr0, implicit $sgpr1, implicit $sgpr2, implicit $sgpr3, implicit $sgpr4, implicit $sgpr5, implicit $sgpr6, implicit $sgpr7
+    renamable $sgpr0_sgpr1_sgpr2_sgpr3_sgpr4_sgpr5_sgpr6_sgpr7 = COPY killed renamable $sgpr4_sgpr5_sgpr6_sgpr7_sgpr8_sgpr9_sgpr10_sgpr11
+    renamable $sgpr1 = S_ADD_I32 0, $sgpr1, implicit-def $scc
+    S_SETPC_B64 $sgpr30_sgpr31, implicit $sgpr0, implicit $sgpr1, implicit $sgpr2, implicit $sgpr3, implicit $sgpr4, implicit $sgpr5, implicit $sgpr6, implicit $sgpr7
+
+...
+
+---
+name: nonoverlapping_copy_kill
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $sgpr30_sgpr31, $sgpr3_sgpr4_sgpr5
+
+    ; CHECK-LABEL: name: nonoverlapping_copy_kill
+    ; CHECK: liveins: $sgpr30_sgpr31, $sgpr3_sgpr4_sgpr5
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: $sgpr0 = S_MOV_B32 $sgpr3, implicit $sgpr3_sgpr4_sgpr5, implicit-def $sgpr0_sgpr1_sgpr2
+    ; CHECK-NEXT: $sgpr1 = S_MOV_B32 $sgpr4, implicit $sgpr3_sgpr4_sgpr5
+    ; CHECK-NEXT: $sgpr2 = S_MOV_B32 $sgpr5, implicit killed $sgpr3_sgpr4_sgpr5
+    ; CHECK-NEXT: renamable $sgpr1 = S_ADD_I32 0, $sgpr1, implicit-def $scc
+    ; CHECK-NEXT: S_SETPC_B64 $sgpr30_sgpr31, implicit $sgpr0, implicit $sgpr1, implicit $sgpr2
+    renamable $sgpr0_sgpr1_sgpr2 = COPY killed renamable $sgpr3_sgpr4_sgpr5
+    renamable $sgpr1 = S_ADD_I32 0, $sgpr1, implicit-def $scc
+    S_SETPC_B64 $sgpr30_sgpr31, implicit $sgpr0, implicit $sgpr1, implicit $sgpr2
+
+...