diff --git a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
index aaefe27b1324f..ea2dc494dabd9 100644
--- a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
@@ -284,6 +284,39 @@ void GCNHazardRecognizer::processBundle() {
   CurrCycleInstr = nullptr;
 }
 
+void GCNHazardRecognizer::processBundleBottomUp() {
+  // Walk through the instructions in this bundle in bottom-up order.
+  // We only use this during post-RA scheduling, so hazard recognizer mode
+  // should never be active here (it always runs top-down).
+  assert(!IsHazardRecognizerMode &&
+         "Bottom-up scheduling shouldn't run in hazard recognizer mode");
+
+  // Step through each instruction in the bundle in bottom-up order.
+  MachineBasicBlock::instr_iterator MI =
+      std::next(CurrCycleInstr->getIterator());
+  MachineBasicBlock::instr_iterator E =
+      CurrCycleInstr->getParent()->instr_end();
+
+  // Evict stale entries to maintain a fixed lookahead window.
+  // TODO: Hazard detection is not yet implemented. This scheduling
+  // is intended for GFX11 and newer.
+  for (; MI != E && MI->isInsideBundle(); ++MI) {
+    CurrCycleInstr = &*MI;
+
+    // Remove up to (MaxLookAhead - 1) oldest entries.
+    for (unsigned I = 0, E = MaxLookAhead - 1; I < E && !EmittedInstrs.empty();
+         ++I)
+      EmittedInstrs.pop_back();
+
+    EmittedInstrs.push_back(CurrCycleInstr);
+
+    // Keep only the most recent MaxLookAhead entries
+    EmittedInstrs.resize(MaxLookAhead);
+  }
+
+  CurrCycleInstr = nullptr;
+}
+
 void GCNHazardRecognizer::runOnInstruction(MachineInstr *MI) {
   assert(IsHazardRecognizerMode);
 
@@ -423,7 +456,41 @@ void GCNHazardRecognizer::AdvanceCycle() {
 }
 
 void GCNHazardRecognizer::RecedeCycle() {
-  llvm_unreachable("hazard recognizer does not support bottom-up scheduling.");
+  // If no instruction was issued this cycle, pop the oldest placeholder.
+  if (!CurrCycleInstr) {
+    if (!EmittedInstrs.empty())
+      EmittedInstrs.pop_back();
+    return;
+  }
+
+  // If this is a bundle header, handle the entire bundle here.
+  if (CurrCycleInstr->isBundle()) {
+    processBundleBottomUp();
+    return;
+  }
+
+  unsigned NumWaitStates = TII.getNumWaitStates(*CurrCycleInstr);
+  if (!NumWaitStates) {
+    CurrCycleInstr = nullptr;
+    return;
+  }
+
+  // Add current instruction to the emitted list.
+  EmittedInstrs.push_back(CurrCycleInstr);
+
+  // Model remaining wait states by removing older placeholders.
+  for (unsigned I = 1, E = std::min(NumWaitStates, getMaxLookAhead()); I < E;
+       ++I) {
+    if (!EmittedInstrs.empty())
+      EmittedInstrs.pop_back();
+  }
+
+  // getMaxLookahead() is the largest number of wait states we will ever need
+  // to insert, so there is no point in keeping track of more than that many
+  // wait states.
+  EmittedInstrs.resize(getMaxLookAhead());
+
+  CurrCycleInstr = nullptr;
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
index bbc55851bf967..88c7426be552d 100644
--- a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
+++ b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.h
@@ -69,6 +69,10 @@ class GCNHazardRecognizer final : public ScheduleHazardRecognizer {
   // Advance over a MachineInstr bundle. Look for hazards in the bundled
   // instructions.
   void processBundle();
+  // Recede over a MachineInstr bundle. Adds bundled instructions to the
+  // EmittedInstrs queue in bottom-up scheduling mode.
+  // TODO: Hazard detection is not yet implemented.
+  void processBundleBottomUp();
 
   // Run on an individual instruction in hazard recognizer mode. This can be
   // used on a newly inserted instruction before returning from PreEmitNoops.
diff --git a/llvm/test/CodeGen/AMDGPU/sched-barrier-post-RA.mir b/llvm/test/CodeGen/AMDGPU/sched-barrier-post-RA.mir
index 7bdb8f5b35ec5..02ebffca84bda 100644
--- a/llvm/test/CodeGen/AMDGPU/sched-barrier-post-RA.mir
+++ b/llvm/test/CodeGen/AMDGPU/sched-barrier-post-RA.mir
@@ -1,5 +1,6 @@
 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
-# RUN: llc -mtriple=amdgcn -mcpu=gfx908 -misched-cluster=false -run-pass=postmisched -verify-misched -o - %s | FileCheck %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx908 -misched-cluster=false -run-pass=postmisched -verify-misched -o - %s | FileCheck -check-prefix=CHECK %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx908 -misched-cluster=false -run-pass=postmisched -misched-postra-direction=bottomup -verify-misched -o - %s | FileCheck -check-prefix=CHECK-BOTTOMUP %s
 
 --- |
   define amdgpu_kernel void @no_sched_barrier(ptr addrspace(1) noalias %out, ptr addrspace(1) noalias %in) { ret void }
@@ -29,6 +30,21 @@ body: |
     ; CHECK-NEXT:   GLOBAL_STORE_DWORD_SADDR killed renamable $vgpr0, killed renamable $vgpr2, killed renamable $sgpr0_sgpr1, 512, 0, implicit $exec :: (store (s32) into %ir.out, !noalias !0, addrspace 1)
     ; CHECK-NEXT: }
     ; CHECK-NEXT: S_ENDPGM 0
+    ;
+    ; CHECK-BOTTOMUP-LABEL: name: no_sched_barrier
+    ; CHECK-BOTTOMUP: renamable $vgpr0 = IMPLICIT_DEF
+    ; CHECK-BOTTOMUP-NEXT: renamable $sgpr0_sgpr1 = IMPLICIT_DEF
+    ; CHECK-BOTTOMUP-NEXT: BUNDLE implicit-def $vgpr1, implicit-def $vgpr1_lo16, implicit-def $vgpr1_hi16, implicit-def $vgpr2, implicit-def $vgpr2_lo16, implicit-def $vgpr2_hi16, implicit $sgpr0_sgpr1, implicit $vgpr0, implicit $exec {
+    ; CHECK-BOTTOMUP-NEXT:   renamable $vgpr1 = GLOBAL_LOAD_DWORD_SADDR renamable $sgpr0_sgpr1, renamable $vgpr0, 0, 0, implicit $exec :: (load (s32) from %ir.in, !alias.scope !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT:   renamable $vgpr2 = GLOBAL_LOAD_DWORD_SADDR renamable $sgpr0_sgpr1, renamable $vgpr0, 512, 0, implicit $exec :: (load (s32) from %ir.in, !alias.scope !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT: }
+    ; CHECK-BOTTOMUP-NEXT: renamable $vgpr1 = nsw V_MUL_LO_U32_e64 killed $vgpr1, $vgpr1, implicit $exec
+    ; CHECK-BOTTOMUP-NEXT: renamable $vgpr2 = nsw V_MUL_LO_U32_e64 killed $vgpr2, $vgpr2, implicit $exec
+    ; CHECK-BOTTOMUP-NEXT: BUNDLE implicit killed $vgpr0, implicit killed $vgpr1, implicit killed $sgpr0_sgpr1, implicit $exec, implicit killed $vgpr2 {
+    ; CHECK-BOTTOMUP-NEXT:   GLOBAL_STORE_DWORD_SADDR renamable $vgpr0, killed renamable $vgpr1, renamable $sgpr0_sgpr1, 0, 0, implicit $exec :: (store (s32) into %ir.out, !noalias !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT:   GLOBAL_STORE_DWORD_SADDR killed renamable $vgpr0, killed renamable $vgpr2, killed renamable $sgpr0_sgpr1, 512, 0, implicit $exec :: (store (s32) into %ir.out, !noalias !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT: }
+    ; CHECK-BOTTOMUP-NEXT: S_ENDPGM 0
     renamable $sgpr0_sgpr1 = IMPLICIT_DEF
     renamable $vgpr0 = IMPLICIT_DEF
     BUNDLE implicit-def $vgpr1, implicit-def $vgpr1_lo16, implicit-def $vgpr1_hi16, implicit-def $vgpr2, implicit-def $vgpr2_lo16, implicit-def $vgpr2_hi16, implicit $sgpr0_sgpr1, implicit $vgpr0, implicit $exec {
@@ -66,6 +82,22 @@ body: |
     ; CHECK-NEXT:   GLOBAL_STORE_DWORD_SADDR killed renamable $vgpr0, killed renamable $vgpr2, killed renamable $sgpr0_sgpr1, 512, 0, implicit $exec :: (store (s32) into %ir.out, !noalias !0, addrspace 1)
     ; CHECK-NEXT: }
     ; CHECK-NEXT: S_ENDPGM 0
+    ;
+    ; CHECK-BOTTOMUP-LABEL: name: sched_barrier_mask_0
+    ; CHECK-BOTTOMUP: renamable $vgpr0 = IMPLICIT_DEF
+    ; CHECK-BOTTOMUP-NEXT: renamable $sgpr0_sgpr1 = IMPLICIT_DEF
+    ; CHECK-BOTTOMUP-NEXT: BUNDLE implicit-def $vgpr1, implicit-def $vgpr1_lo16, implicit-def $vgpr1_hi16, implicit-def $vgpr2, implicit-def $vgpr2_lo16, implicit-def $vgpr2_hi16, implicit $sgpr0_sgpr1, implicit $vgpr0, implicit $exec {
+    ; CHECK-BOTTOMUP-NEXT:   renamable $vgpr1 = GLOBAL_LOAD_DWORD_SADDR renamable $sgpr0_sgpr1, renamable $vgpr0, 0, 0, implicit $exec :: (load (s32) from %ir.in, !alias.scope !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT:   renamable $vgpr2 = GLOBAL_LOAD_DWORD_SADDR renamable $sgpr0_sgpr1, renamable $vgpr0, 512, 0, implicit $exec :: (load (s32) from %ir.in, !alias.scope !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT: }
+    ; CHECK-BOTTOMUP-NEXT: renamable $vgpr1 = nsw V_MUL_LO_U32_e64 killed $vgpr1, $vgpr1, implicit $exec
+    ; CHECK-BOTTOMUP-NEXT: SCHED_BARRIER 0
+    ; CHECK-BOTTOMUP-NEXT: renamable $vgpr2 = nsw V_MUL_LO_U32_e64 killed $vgpr2, $vgpr2, implicit $exec
+    ; CHECK-BOTTOMUP-NEXT: BUNDLE implicit killed $vgpr0, implicit killed $vgpr1, implicit killed $sgpr0_sgpr1, implicit $exec, implicit killed $vgpr2 {
+    ; CHECK-BOTTOMUP-NEXT:   GLOBAL_STORE_DWORD_SADDR renamable $vgpr0, killed renamable $vgpr1, renamable $sgpr0_sgpr1, 0, 0, implicit $exec :: (store (s32) into %ir.out, !noalias !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT:   GLOBAL_STORE_DWORD_SADDR killed renamable $vgpr0, killed renamable $vgpr2, killed renamable $sgpr0_sgpr1, 512, 0, implicit $exec :: (store (s32) into %ir.out, !noalias !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT: }
+    ; CHECK-BOTTOMUP-NEXT: S_ENDPGM 0
     renamable $sgpr0_sgpr1 = IMPLICIT_DEF
     renamable $vgpr0 = IMPLICIT_DEF
     BUNDLE implicit-def $vgpr1, implicit-def $vgpr1_lo16, implicit-def $vgpr1_hi16, implicit-def $vgpr2, implicit-def $vgpr2_lo16, implicit-def $vgpr2_hi16, implicit $sgpr0_sgpr1, implicit $vgpr0, implicit $exec {
@@ -105,6 +137,22 @@ body: |
     ; CHECK-NEXT:   GLOBAL_STORE_DWORD_SADDR killed renamable $vgpr0, killed renamable $vgpr2, killed renamable $sgpr0_sgpr1, 512, 0, implicit $exec :: (store (s32) into %ir.out, !noalias !0, addrspace 1)
     ; CHECK-NEXT: }
     ; CHECK-NEXT: S_ENDPGM 0
+    ;
+    ; CHECK-BOTTOMUP-LABEL: name: sched_barrier_mask_1
+    ; CHECK-BOTTOMUP: renamable $vgpr0 = IMPLICIT_DEF
+    ; CHECK-BOTTOMUP-NEXT: renamable $sgpr0_sgpr1 = IMPLICIT_DEF
+    ; CHECK-BOTTOMUP-NEXT: BUNDLE implicit-def $vgpr1, implicit-def $vgpr1_lo16, implicit-def $vgpr1_hi16, implicit-def $vgpr2, implicit-def $vgpr2_lo16, implicit-def $vgpr2_hi16, implicit $sgpr0_sgpr1, implicit $vgpr0, implicit $exec {
+    ; CHECK-BOTTOMUP-NEXT:   renamable $vgpr1 = GLOBAL_LOAD_DWORD_SADDR renamable $sgpr0_sgpr1, renamable $vgpr0, 0, 0, implicit $exec :: (load (s32) from %ir.in, !alias.scope !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT:   renamable $vgpr2 = GLOBAL_LOAD_DWORD_SADDR renamable $sgpr0_sgpr1, renamable $vgpr0, 512, 0, implicit $exec :: (load (s32) from %ir.in, !alias.scope !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT: }
+    ; CHECK-BOTTOMUP-NEXT: renamable $vgpr1 = nsw V_MUL_LO_U32_e64 killed $vgpr1, $vgpr1, implicit $exec
+    ; CHECK-BOTTOMUP-NEXT: renamable $vgpr2 = nsw V_MUL_LO_U32_e64 killed $vgpr2, $vgpr2, implicit $exec
+    ; CHECK-BOTTOMUP-NEXT: SCHED_BARRIER 1
+    ; CHECK-BOTTOMUP-NEXT: BUNDLE implicit killed $vgpr0, implicit killed $vgpr1, implicit killed $sgpr0_sgpr1, implicit $exec, implicit killed $vgpr2 {
+    ; CHECK-BOTTOMUP-NEXT:   GLOBAL_STORE_DWORD_SADDR renamable $vgpr0, killed renamable $vgpr1, renamable $sgpr0_sgpr1, 0, 0, implicit $exec :: (store (s32) into %ir.out, !noalias !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT:   GLOBAL_STORE_DWORD_SADDR killed renamable $vgpr0, killed renamable $vgpr2, killed renamable $sgpr0_sgpr1, 512, 0, implicit $exec :: (store (s32) into %ir.out, !noalias !0, addrspace 1)
+    ; CHECK-BOTTOMUP-NEXT: }
+    ; CHECK-BOTTOMUP-NEXT: S_ENDPGM 0
     renamable $sgpr0_sgpr1 = IMPLICIT_DEF
     renamable $vgpr0 = IMPLICIT_DEF
     BUNDLE implicit-def $vgpr1, implicit-def $vgpr1_lo16, implicit-def $vgpr1_hi16, implicit-def $vgpr2, implicit-def $vgpr2_lo16, implicit-def $vgpr2_hi16, implicit $sgpr0_sgpr1, implicit $vgpr0, implicit $exec {