[llvm] AMDGPU: Handle av imm pseudo in si-fix-sgpr-copies phi fold (PR #149263)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/149263

None

>From c5797ce35c1393b63d79dc24539463f6bdf441ef Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Thu, 17 Jul 2025 10:21:48 +0900
Subject: [PATCH] AMDGPU: Handle av imm pseudo in si-fix-sgpr-copies phi fold

---
 llvm/lib/Target/AMDGPU/SIFixSGPRCopies.cpp    |  1 +
 .../CodeGen/AMDGPU/phi-vgpr-input-moveimm.mir | 56 +++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/llvm/lib/Target/AMDGPU/SIFixSGPRCopies.cpp b/llvm/lib/Target/AMDGPU/SIFixSGPRCopies.cpp
index 9b5a46395695d..44d9ef5a0792e 100644
--- a/llvm/lib/Target/AMDGPU/SIFixSGPRCopies.cpp
+++ b/llvm/lib/Target/AMDGPU/SIFixSGPRCopies.cpp
@@ -378,6 +378,7 @@ static bool isSafeToFoldImmIntoCopy(const MachineInstr *Copy,
   default:
     return false;
   case AMDGPU::V_MOV_B32_e32:
+  case AMDGPU::AV_MOV_B32_IMM_PSEUDO:
     SMovOp = AMDGPU::S_MOV_B32;
     break;
   case AMDGPU::V_MOV_B64_PSEUDO:
diff --git a/llvm/test/CodeGen/AMDGPU/phi-vgpr-input-moveimm.mir b/llvm/test/CodeGen/AMDGPU/phi-vgpr-input-moveimm.mir
index c2c5340639a16..8145a1d7a2072 100644
--- a/llvm/test/CodeGen/AMDGPU/phi-vgpr-input-moveimm.mir
+++ b/llvm/test/CodeGen/AMDGPU/phi-vgpr-input-moveimm.mir
@@ -167,3 +167,59 @@ body:             |
     %1:sreg_32 = COPY %0
     S_BRANCH %bb.2
 ...
+
+---
+
+name:            phi_moveimm_av_pseudo_input
+tracksRegLiveness: true
+body:             |
+  ; GCN-LABEL: name: phi_moveimm_av_pseudo_input
+  ; GCN: bb.0:
+  ; GCN-NEXT:   successors: %bb.1(0x80000000)
+  ; GCN-NEXT:   liveins: $sgpr0, $sgpr1
+  ; GCN-NEXT: {{  $}}
+  ; GCN-NEXT:   [[AV_MOV_:%[0-9]+]]:vgpr_32 = AV_MOV_B32_IMM_PSEUDO 0, implicit $exec
+  ; GCN-NEXT:   [[COPY:%[0-9]+]]:sreg_32 = COPY $sgpr0
+  ; GCN-NEXT:   [[COPY1:%[0-9]+]]:sreg_32 = COPY $sgpr1
+  ; GCN-NEXT: {{  $}}
+  ; GCN-NEXT: bb.1:
+  ; GCN-NEXT:   successors: %bb.2(0x80000000)
+  ; GCN-NEXT: {{  $}}
+  ; GCN-NEXT:   [[S_ADD_U32_:%[0-9]+]]:sreg_32 = S_ADD_U32 [[COPY]], [[COPY1]], implicit-def $scc
+  ; GCN-NEXT:   S_BRANCH %bb.2
+  ; GCN-NEXT: {{  $}}
+  ; GCN-NEXT: bb.2:
+  ; GCN-NEXT:   successors: %bb.3(0x80000000)
+  ; GCN-NEXT: {{  $}}
+  ; GCN-NEXT:   [[PHI:%[0-9]+]]:sreg_32 = PHI %5, %bb.3, [[S_ADD_U32_]], %bb.1
+  ; GCN-NEXT:   S_BRANCH %bb.3
+  ; GCN-NEXT: {{  $}}
+  ; GCN-NEXT: bb.3:
+  ; GCN-NEXT:   successors: %bb.2(0x80000000)
+  ; GCN-NEXT: {{  $}}
+  ; GCN-NEXT:   [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 0
+  ; GCN-NEXT:   S_BRANCH %bb.2
+  bb.0:
+    successors: %bb.1
+    liveins: $sgpr0, $sgpr1
+
+    %0:vgpr_32 = AV_MOV_B32_IMM_PSEUDO 0, implicit $exec
+
+    %4:sreg_32 = COPY $sgpr0
+    %5:sreg_32 = COPY $sgpr1
+
+  bb.1:
+    successors: %bb.2
+    %2:sreg_32 = S_ADD_U32 %4, %5, implicit-def $scc
+    S_BRANCH %bb.2
+
+  bb.2:
+    successors: %bb.3
+    %3:sreg_32 = PHI %1, %bb.3, %2, %bb.1
+    S_BRANCH %bb.3
+
+  bb.3:
+    successors: %bb.2
+    %1:sreg_32 = COPY %0
+    S_BRANCH %bb.2
+...