[llvm] [AMDGPU] misched: avoid subregister dependencies (PR #140255)

Robert Imschweiler via llvm-commits llvm-commits at lists.llvm.org
Fri May 16 12:27:57 PDT 2025


https://github.com/ro-i updated https://github.com/llvm/llvm-project/pull/140255

>From b851dd6a29a3c148c05330e866e194d172f41b2b Mon Sep 17 00:00:00 2001
From: Robert Imschweiler <robert.imschweiler at amd.com>
Date: Thu, 15 May 2025 12:01:36 -0500
Subject: [PATCH 1/2] [AMDGPU] misched: avoid subregister dependencies

There are some VOP3P instructions which operate on packed 32bit values
and can be configured (op_sel/op_sel_hi) to only use one of the values.
This patch adapts the scheduling dependencies so that a write to vgpr3,
for example, is not a data dependency for a read from vgpr2_vgpr3 in
case only vgpr2 is actually used.
---
 llvm/lib/Target/AMDGPU/GCNSubtarget.cpp       |  61 ++++++++
 llvm/lib/Target/AMDGPU/GCNSubtarget.h         |  11 ++
 .../AMDGPU/llvm.amdgcn.iglp.opt.exp.large.mir | 141 +++++++++---------
 .../AMDGPU/llvm.amdgcn.iglp.opt.exp.small.mir | 138 ++++++++---------
 .../CodeGen/AMDGPU/packed-dependencies.mir    |  49 ++++++
 5 files changed, 261 insertions(+), 139 deletions(-)
 create mode 100644 llvm/test/CodeGen/AMDGPU/packed-dependencies.mir

diff --git a/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp b/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp
index d6153ce93b451..843aca57be2bf 100644
--- a/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp
@@ -535,6 +535,62 @@ unsigned GCNSubtarget::getMaxNumVGPRs(const MachineFunction &MF) const {
   return getBaseMaxNumVGPRs(F, MFI.getWavesPerEU());
 }
 
+bool GCNSubtarget::isRealSchedDependency(MachineInstr *DefI, int DefOpIdx,
+                                         MachineInstr *UseI,
+                                         int UseOpIdx) const {
+  if (!InstrInfo.isVOP3P(*UseI))
+    return true;
+  MachineOperand &DefOp = DefI->getOperand(DefOpIdx);
+  if (!DefOp.isReg() || !DefOp.getReg().isPhysical())
+    return true;
+
+  AMDGPU::OpName UseModName;
+  if (AMDGPU::getNamedOperandIdx(UseI->getOpcode(), AMDGPU::OpName::src0) ==
+      UseOpIdx)
+    UseModName = AMDGPU::OpName::src0_modifiers;
+  else if (AMDGPU::getNamedOperandIdx(UseI->getOpcode(),
+                                      AMDGPU::OpName::src1) == UseOpIdx)
+    UseModName = AMDGPU::OpName::src1_modifiers;
+  else if (AMDGPU::getNamedOperandIdx(UseI->getOpcode(),
+                                      AMDGPU::OpName::src2) == UseOpIdx)
+    UseModName = AMDGPU::OpName::src2_modifiers;
+  else
+    return true;
+  MachineOperand *UseOpMod = InstrInfo.getNamedOperand(*UseI, UseModName);
+  if (!UseOpMod)
+    return true;
+  // Check whether all parts of the register are being used (= op_sel and
+  // op_sel_hi differ). In that case we can return early.
+  auto OpSel = UseOpMod->getImm() & SISrcMods::OP_SEL_0;
+  auto OpSelHi = UseOpMod->getImm() & SISrcMods::OP_SEL_1;
+  if ((!OpSel || !OpSelHi) && (OpSel || OpSelHi))
+    return true;
+
+  MachineOperand &UseOp = UseI->getOperand(UseOpIdx);
+  if (!UseOp.isReg() || !UseOp.getReg().isPhysical())
+    return true;
+  const SIRegisterInfo *TRI = getRegisterInfo();
+  const MachineRegisterInfo &MRI = UseI->getParent()->getParent()->getRegInfo();
+  MCRegister DefReg = DefOp.getReg().asMCReg();
+  MCRegister UseReg = UseOp.getReg().asMCReg();
+  // We specifically look for a packed 32bit Use and smaller Def.
+  if (TRI->getRegSizeInBits(UseReg, MRI) != 64 ||
+      TRI->getRegSizeInBits(DefReg, MRI) > 32)
+    return true;
+  SmallVector<MCRegUnit, 2> DefRegUnits(TRI->regunits(DefReg));
+  assert(DefRegUnits.size() <= 2 && "unexpected number of register units");
+  SmallVector<MCRegUnit, 4> UseRegUnits(TRI->regunits(UseReg));
+  assert(UseRegUnits.size() == 4 && "unexpected number of register units");
+
+  auto FindRegunit = [&DefRegUnits](MCRegUnit A, MCRegUnit B) {
+    return llvm::find_if(DefRegUnits, [A, B](MCRegUnit RU) {
+             return RU == A || RU == B;
+           }) != DefRegUnits.end();
+  };
+  return OpSel ? FindRegunit(UseRegUnits[2], UseRegUnits[3])
+               : FindRegunit(UseRegUnits[0], UseRegUnits[1]);
+}
+
 void GCNSubtarget::adjustSchedDependency(
     SUnit *Def, int DefOpIdx, SUnit *Use, int UseOpIdx, SDep &Dep,
     const TargetSchedModel *SchedModel) const {
@@ -545,6 +601,11 @@ void GCNSubtarget::adjustSchedDependency(
   MachineInstr *DefI = Def->getInstr();
   MachineInstr *UseI = Use->getInstr();
 
+  if (!isRealSchedDependency(DefI, DefOpIdx, UseI, UseOpIdx)) {
+    Dep = SDep(Def, SDep::Artificial);
+    return; // this is not a data dependency anymore
+  }
+
   if (DefI->isBundle()) {
     const SIRegisterInfo *TRI = getRegisterInfo();
     auto Reg = Dep.getReg();
diff --git a/llvm/lib/Target/AMDGPU/GCNSubtarget.h b/llvm/lib/Target/AMDGPU/GCNSubtarget.h
index fea17baa17722..edee53a53a2d0 100644
--- a/llvm/lib/Target/AMDGPU/GCNSubtarget.h
+++ b/llvm/lib/Target/AMDGPU/GCNSubtarget.h
@@ -272,6 +272,17 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
   SITargetLowering TLInfo;
   SIFrameLowering FrameLowering;
 
+  /// From the (MI300) ISA:
+  /// "Packed 32-bit instructions operate on 2 dwords at a time and those
+  /// operands must be two-dword aligned (i.e. an even VGPR address). Output
+  /// modifiers are not supported for these instructions. OPSEL and OPSEL_HI
+  /// work to select the first or second DWORD for each source."
+  /// -> We can save dependencies on VGPRs by analyzing the operand selection.
+  /// See also
+  /// https://llvm.org/docs/AMDGPUModifierSyntax.html#amdgpu-synid-op-sel
+  bool isRealSchedDependency(MachineInstr *DefI, int DefOpIdx,
+                             MachineInstr *UseI, int UseOpIdx) const;
+
 public:
   GCNSubtarget(const Triple &TT, StringRef GPU, StringRef FS,
                const GCNTargetMachine &TM);
diff --git a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.iglp.opt.exp.large.mir b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.iglp.opt.exp.large.mir
index aad6e031aa9ed..6c4ebef38057b 100644
--- a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.iglp.opt.exp.large.mir
+++ b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.iglp.opt.exp.large.mir
@@ -464,16 +464,10 @@
   ; GCN-NEXT:    buffer_load_dwordx2 v[130:131], v64, s[0:3], 0 offen sc0 sc1
   ; GCN-NEXT:    s_waitcnt vmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
-  ; GCN-NEXT:    v_fma_f32 v57, s4, v57, -v134
   ; GCN-NEXT:    v_fma_f32 v48, s4, v48, -v134
-  ; GCN-NEXT:    v_fma_f32 v96, s4, v58, -v134
-  ; GCN-NEXT:    v_mul_f32_e32 v57, 0x3fb8aa3b, v57
   ; GCN-NEXT:    v_mul_f32_e32 v48, 0x3fb8aa3b, v48
   ; GCN-NEXT:    v_fma_f32 v64, s4, v49, -v134
-  ; GCN-NEXT:    v_exp_f32_e32 v163, v57
-  ; GCN-NEXT:    v_mul_f32_e32 v57, 0x3fb8aa3b, v96
   ; GCN-NEXT:    v_fma_f32 v66, s4, v50, -v134
-  ; GCN-NEXT:    v_exp_f32_e32 v164, v57
   ; GCN-NEXT:    v_exp_f32_e32 v49, v48
   ; GCN-NEXT:    v_mul_f32_e32 v48, 0x3fb8aa3b, v64
   ; GCN-NEXT:    v_fma_f32 v67, s4, v51, -v134
@@ -495,25 +489,27 @@
   ; GCN-NEXT:    ds_read_b128 v[140:143], v139
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
+  ; GCN-NEXT:    ds_read_b128 v[144:147], v139 offset:576
+  ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
+  ; GCN-NEXT:    buffer_inv sc0 sc1
   ; GCN-NEXT:    v_exp_f32_e32 v54, v48
   ; GCN-NEXT:    v_mul_f32_e32 v48, 0x3fb8aa3b, v70
   ; GCN-NEXT:    v_exp_f32_e32 v55, v48
   ; GCN-NEXT:    v_mul_f32_e32 v48, 0x3fb8aa3b, v71
-  ; GCN-NEXT:    ds_read_b128 v[144:147], v139 offset:576
-  ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
-  ; GCN-NEXT:    buffer_inv sc0 sc1
   ; GCN-NEXT:    v_fma_f32 v66, s4, v56, -v134
   ; GCN-NEXT:    v_exp_f32_e32 v56, v48
   ; GCN-NEXT:    v_sub_f32_e32 v48, v65, v134
+  ; GCN-NEXT:    ds_read_b128 v[148:151], v139 offset:1152
+  ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
+  ; GCN-NEXT:    buffer_inv sc0 sc1
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v64, v49
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v67, v50
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v68, v51
+  ; GCN-NEXT:    v_fma_f32 v96, s4, v58, -v134
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v58, v52
   ; GCN-NEXT:    v_mul_f32_e32 v48, 0x3fb8aa3b, v48
-  ; GCN-NEXT:    ds_read_b128 v[148:151], v139 offset:1152
-  ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
-  ; GCN-NEXT:    buffer_inv sc0 sc1
   ; GCN-NEXT:    v_exp_f32_e32 v48, v48
+  ; GCN-NEXT:    v_fma_f32 v57, s4, v57, -v134
   ; GCN-NEXT:    v_pack_b32_f16 v161, v68, v58
   ; GCN-NEXT:    v_pack_b32_f16 v160, v64, v67
   ; GCN-NEXT:    v_mul_f32_e32 v58, 0x3fb8aa3b, v66
@@ -521,9 +517,7 @@
   ; GCN-NEXT:    ds_read_b128 v[152:155], v139 offset:1728
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
-  ; GCN-NEXT:    v_fma_f32 v162, s4, v61, -v134
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v61, v55
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v57, v56
+  ; GCN-NEXT:    ; implicit-def: $vgpr80_vgpr81_vgpr82_vgpr83_vgpr84_vgpr85_vgpr86_vgpr87_vgpr88_vgpr89_vgpr90_vgpr91_vgpr92_vgpr93_vgpr94_vgpr95
   ; GCN-NEXT:    v_pk_mul_f32 v[64:65], v[64:65], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[66:67], v[66:67], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[68:69], v[68:69], v[48:49] op_sel_hi:[1,0]
@@ -532,10 +526,8 @@
   ; GCN-NEXT:    v_pk_mul_f32 v[74:75], v[74:75], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[76:77], v[76:77], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[78:79], v[78:79], v[48:49] op_sel_hi:[1,0]
-  ; GCN-NEXT:    ; implicit-def: $vgpr80_vgpr81_vgpr82_vgpr83_vgpr84_vgpr85_vgpr86_vgpr87_vgpr88_vgpr89_vgpr90_vgpr91_vgpr92_vgpr93_vgpr94_vgpr95
-  ; GCN-NEXT:    v_fma_f32 v59, s4, v59, -v134
+  ; GCN-NEXT:    v_mul_f32_e32 v57, 0x3fb8aa3b, v57
   ; GCN-NEXT:    v_pk_mul_f32 v[80:81], v[80:81], v[48:49] op_sel_hi:[1,0]
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[140:141], v[160:161], v[64:79]
   ; GCN-NEXT:    v_pk_mul_f32 v[82:83], v[82:83], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[84:85], v[84:85], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[86:87], v[86:87], v[48:49] op_sel_hi:[1,0]
@@ -543,10 +535,20 @@
   ; GCN-NEXT:    v_pk_mul_f32 v[90:91], v[90:91], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[92:93], v[92:93], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[94:95], v[94:95], v[48:49] op_sel_hi:[1,0]
-  ; GCN-NEXT:    ; implicit-def: $vgpr96_vgpr97_vgpr98_vgpr99_vgpr100_vgpr101_vgpr102_vgpr103_vgpr104_vgpr105_vgpr106_vgpr107_vgpr108_vgpr109_vgpr110_vgpr111
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[140:141], v[160:161], v[64:79]
   ; GCN-NEXT:    v_exp_f32_e32 v58, v58
-  ; GCN-NEXT:    v_pk_mul_f32 v[96:97], v[96:97], v[48:49] op_sel_hi:[1,0]
+  ; GCN-NEXT:    v_fma_f32 v162, s4, v61, -v134
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v61, v55
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v140, v53
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v141, v54
+  ; GCN-NEXT:    v_fma_f32 v59, s4, v59, -v134
+  ; GCN-NEXT:    v_fma_f32 v60, s4, v60, -v134
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[80:95], v[144:145], v[160:161], v[80:95]
+  ; GCN-NEXT:    v_exp_f32_e32 v163, v57
+  ; GCN-NEXT:    v_mul_f32_e32 v57, 0x3fb8aa3b, v96
+  ; GCN-NEXT:    ; implicit-def: $vgpr96_vgpr97_vgpr98_vgpr99_vgpr100_vgpr101_vgpr102_vgpr103_vgpr104_vgpr105_vgpr106_vgpr107_vgpr108_vgpr109_vgpr110_vgpr111
+  ; GCN-NEXT:    v_pk_mul_f32 v[112:113], v[112:113], v[48:49] op_sel_hi:[1,0]
+  ; GCN-NEXT:    v_pk_mul_f32 v[96:97], v[96:97], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[98:99], v[98:99], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[100:101], v[100:101], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[102:103], v[102:103], v[48:49] op_sel_hi:[1,0]
@@ -554,35 +556,33 @@
   ; GCN-NEXT:    v_pk_mul_f32 v[106:107], v[106:107], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[108:109], v[108:109], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[110:111], v[110:111], v[48:49] op_sel_hi:[1,0]
-  ; GCN-NEXT:    v_pack_b32_f16 v145, v61, v57
-  ; GCN-NEXT:    v_mul_f32_e32 v57, 0x3fb8aa3b, v59
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v140, v53
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v141, v54
-  ; GCN-NEXT:    v_exp_f32_e32 v59, v57
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[96:111], v[148:149], v[160:161], v[96:111]
-  ; GCN-NEXT:    v_fma_f32 v60, s4, v60, -v134
-  ; GCN-NEXT:    v_pk_mul_f32 v[112:113], v[112:113], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[114:115], v[114:115], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[116:117], v[116:117], v[48:49] op_sel_hi:[1,0]
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[96:111], v[148:149], v[160:161], v[96:111]
+  ; GCN-NEXT:    v_exp_f32_e32 v164, v57
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v57, v56
   ; GCN-NEXT:    v_pk_mul_f32 v[118:119], v[118:119], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[120:121], v[120:121], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[122:123], v[122:123], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[124:125], v[124:125], v[48:49] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[126:127], v[126:127], v[48:49] op_sel_hi:[1,0]
+  ; GCN-NEXT:    v_pack_b32_f16 v145, v61, v57
+  ; GCN-NEXT:    v_mul_f32_e32 v57, 0x3fb8aa3b, v59
   ; GCN-NEXT:    v_fma_f32 v148, s4, v62, -v134
-  ; GCN-NEXT:    v_pack_b32_f16 v144, v140, v141
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[112:127], v[152:153], v[160:161], v[112:127]
   ; GCN-NEXT:    v_fma_f32 v152, s4, v63, -v134
+  ; GCN-NEXT:    v_pack_b32_f16 v144, v140, v141
+  ; GCN-NEXT:    v_exp_f32_e32 v59, v57
   ; GCN-NEXT:    v_mul_f32_e32 v149, 0x3fb8aa3b, v60
   ; GCN-NEXT:    ; implicit-def: $vgpr57
   ; GCN-NEXT:    ds_read_b128 v[60:63], v57
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
-  ; GCN-NEXT:    v_exp_f32_e32 v160, v149
   ; GCN-NEXT:    v_fma_f32 v161, s4, v33, -v134
   ; GCN-NEXT:    v_mul_f32_e32 v33, 0x3fb8aa3b, v148
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v153, v58
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[142:143], v[144:145], v[64:79]
+  ; GCN-NEXT:    v_exp_f32_e32 v160, v149
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v153, v58
   ; GCN-NEXT:    v_fma_f32 v32, s4, v32, -v134
   ; GCN-NEXT:    ds_read_b128 v[140:143], v57 offset:576
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
@@ -590,22 +590,20 @@
   ; GCN-NEXT:    v_fma_f32 v40, s4, v40, -v134
   ; GCN-NEXT:    v_fma_f32 v44, s4, v44, -v134
   ; GCN-NEXT:    v_fma_f32 v16, s4, v16, -v134
-  ; GCN-NEXT:    v_fma_f32 v166, s4, v20, -v134
-  ; GCN-NEXT:    v_fma_f32 v24, s4, v24, -v134
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[80:95], v[146:147], v[144:145], v[80:95]
   ; GCN-NEXT:    v_mul_f32_e32 v146, 0x3fb8aa3b, v162
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v147, v163
   ; GCN-NEXT:    v_exp_f32_e32 v162, v146
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v146, v164
-  ; GCN-NEXT:    v_fma_f32 v28, s4, v28, -v134
+  ; GCN-NEXT:    v_fma_f32 v166, s4, v20, -v134
   ; GCN-NEXT:    v_pack_b32_f16 v148, v153, v147
-  ; GCN-NEXT:    v_fma_f32 v0, s4, v0, -v134
+  ; GCN-NEXT:    v_fma_f32 v24, s4, v24, -v134
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[96:111], v[150:151], v[144:145], v[96:111]
   ; GCN-NEXT:    v_exp_f32_e32 v151, v33
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v33, v59
   ; GCN-NEXT:    v_fma_f32 v150, s4, v34, -v134
-  ; GCN-NEXT:    v_fma_f32 v8, s4, v8, -v134
-  ; GCN-NEXT:    v_fma_f32 v12, s4, v12, -v134
+  ; GCN-NEXT:    v_fma_f32 v28, s4, v28, -v134
+  ; GCN-NEXT:    v_fma_f32 v0, s4, v0, -v134
   ; GCN-NEXT:    v_pack_b32_f16 v149, v146, v33
   ; GCN-NEXT:    v_mul_f32_e32 v33, 0x3fb8aa3b, v152
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[112:127], v[154:155], v[144:145], v[112:127]
@@ -614,6 +612,8 @@
   ; GCN-NEXT:    v_fma_f32 v155, s4, v36, -v134
   ; GCN-NEXT:    v_perm_b32 v36, v158, v156, s5
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v154, v160
+  ; GCN-NEXT:    v_fma_f32 v8, s4, v8, -v134
+  ; GCN-NEXT:    v_fma_f32 v12, s4, v12, -v134
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[60:61], v[148:149], v[64:79]
   ; GCN-NEXT:    v_mul_f32_e32 v60, 0x3fb8aa3b, v32
   ; GCN-NEXT:    ds_read_b128 v[32:35], v57 offset:1152
@@ -787,12 +787,14 @@
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v45, v158
   ; GCN-NEXT:    v_perm_b32 v21, v148, v144, s5
   ; GCN-NEXT:    v_perm_b32 v37, v148, v144, s8
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v44, v63
   ; GCN-NEXT:    ;;#ASMSTART
   ; GCN-NEXT:    s_waitcnt vmcnt(8)
   ; GCN-NEXT:    ;;#ASMEND
   ; GCN-NEXT:    buffer_wbl2 sc0 sc1
   ; GCN-NEXT:    ds_write_b64 v135, v[20:21]
+  ; GCN-NEXT:    buffer_wbl2 sc0 sc1
+  ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
+  ; GCN-NEXT:    ds_write_b64 v136, v[36:37]
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[96:111], v[16:17], v[40:41], v[96:111]
   ; GCN-NEXT:    v_perm_b32 v16, v141, v131, s5
   ; GCN-NEXT:    v_fma_f32 v131, s4, v22, -v134
@@ -802,23 +804,19 @@
   ; GCN-NEXT:    v_perm_b32 v17, v149, v145, s5
   ; GCN-NEXT:    buffer_wbl2 sc0 sc1
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
-  ; GCN-NEXT:    ds_write_b64 v136, v[36:37]
+  ; GCN-NEXT:    ds_write_b64 v137, v[16:17]
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[112:127], v[32:33], v[40:41], v[112:127]
   ; GCN-NEXT:    v_pack_b32_f16 v33, v45, v22
   ; GCN-NEXT:    v_mul_f32_e32 v22, 0x3fb8aa3b, v60
   ; GCN-NEXT:    v_exp_f32_e32 v144, v22
-  ; GCN-NEXT:    buffer_wbl2 sc0 sc1
-  ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
-  ; GCN-NEXT:    ds_write_b64 v137, v[16:17]
   ; GCN-NEXT:    ; implicit-def: $vgpr17
   ; GCN-NEXT:    ; implicit-def: $vgpr22
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v44, v63
   ; GCN-NEXT:    buffer_wbl2 sc0 sc1
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    ds_write_b64 v138, v[42:43]
   ; GCN-NEXT:    v_add_u32_e32 v22, v132, v22
   ; GCN-NEXT:    v_add_u32_e32 v17, v132, v17
-  ; GCN-NEXT:    ; implicit-def: $vgpr20
-  ; GCN-NEXT:    ; implicit-def: $vgpr21
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_load_dwordx2 v[40:41], v22, s[0:3], 0 offen sc0 sc1
   ; GCN-NEXT:    s_waitcnt vmcnt(0)
@@ -826,9 +824,11 @@
   ; GCN-NEXT:    buffer_load_dwordx2 v[42:43], v17, s[0:3], 0 offen sc0 sc1
   ; GCN-NEXT:    s_waitcnt vmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
+  ; GCN-NEXT:    ; implicit-def: $vgpr20
+  ; GCN-NEXT:    ; implicit-def: $vgpr21
+  ; GCN-NEXT:    v_pack_b32_f16 v32, v61, v44
   ; GCN-NEXT:    v_add_u32_e32 v20, v132, v20
   ; GCN-NEXT:    v_add_u32_e32 v21, v132, v21
-  ; GCN-NEXT:    v_pack_b32_f16 v32, v61, v44
   ; GCN-NEXT:    buffer_load_dwordx2 v[44:45], v20, s[0:3], 0 offen sc0 sc1
   ; GCN-NEXT:    s_waitcnt vmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
@@ -959,27 +959,27 @@
   ; GCN-NEXT:    buffer_wbl2 sc0 sc1
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    ds_write_b64 v136, v[20:21]
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[112:127], v[16:17], v[24:25], v[112:127]
+  ; GCN-NEXT:    v_pack_b32_f16 v17, v40, v6
+  ; GCN-NEXT:    v_mul_f32_e32 v6, 0x3fb8aa3b, v32
   ; GCN-NEXT:    buffer_wbl2 sc0 sc1
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    ds_write_b64 v137, v[0:1]
   ; GCN-NEXT:    buffer_wbl2 sc0 sc1
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    ds_write_b64 v138, v[26:27]
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[112:127], v[16:17], v[24:25], v[112:127]
-  ; GCN-NEXT:    v_pack_b32_f16 v17, v40, v6
-  ; GCN-NEXT:    v_mul_f32_e32 v6, 0x3fb8aa3b, v32
+  ; GCN-NEXT:    v_exp_f32_e32 v25, v6
   ; GCN-NEXT:    ;;#ASMSTART
   ; GCN-NEXT:    s_waitcnt vmcnt(8)
   ; GCN-NEXT:    ;;#ASMEND
   ; GCN-NEXT:    v_pack_b32_f16 v16, v37, v28
   ; GCN-NEXT:    v_fma_f32 v24, s4, v7, -v134
-  ; GCN-NEXT:    v_exp_f32_e32 v25, v6
+  ; GCN-NEXT:    v_mul_f32_e32 v0, 0x3fb8aa3b, v149
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    ds_read_b128 v[4:7], v139
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[22:23], v[16:17], v[64:79]
-  ; GCN-NEXT:    v_mul_f32_e32 v0, 0x3fb8aa3b, v149
   ; GCN-NEXT:    v_exp_f32_e32 v26, v0
   ; GCN-NEXT:    v_mul_f32_e32 v0, 0x3fb8aa3b, v29
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v1, v150
@@ -998,13 +998,13 @@
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v0, v25
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[112:127], v[18:19], v[16:17], v[112:127]
   ; GCN-NEXT:    v_pack_b32_f16 v17, v2, v0
-  ; GCN-NEXT:    v_pack_b32_f16 v16, v1, v27
   ; GCN-NEXT:    v_mul_f32_e32 v0, 0x3fb8aa3b, v24
-  ; GCN-NEXT:    v_fma_f32 v18, s4, v11, -v134
+  ; GCN-NEXT:    v_pack_b32_f16 v16, v1, v27
   ; GCN-NEXT:    v_exp_f32_e32 v19, v0
   ; GCN-NEXT:    ds_read_b128 v[0:3], v139 offset:1152
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
+  ; GCN-NEXT:    v_fma_f32 v18, s4, v11, -v134
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[4:5], v[16:17], v[64:79]
   ; GCN-NEXT:    v_mul_f32_e32 v4, 0x3fb8aa3b, v8
   ; GCN-NEXT:    ds_read_b128 v[8:11], v139 offset:1728
@@ -1013,41 +1013,41 @@
   ; GCN-NEXT:    v_exp_f32_e32 v24, v4
   ; GCN-NEXT:    v_mul_f32_e32 v4, 0x3fb8aa3b, v28
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v5, v26
-  ; GCN-NEXT:    v_exp_f32_e32 v27, v4
-  ; GCN-NEXT:    v_mul_f32_e32 v4, 0x3fb8aa3b, v18
+  ; GCN-NEXT:    v_fma_f32 v28, s4, v14, -v134
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[80:95], v[20:21], v[16:17], v[80:95]
+  ; GCN-NEXT:    v_exp_f32_e32 v27, v4
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v20, v29
+  ; GCN-NEXT:    v_mul_f32_e32 v4, 0x3fb8aa3b, v18
   ; GCN-NEXT:    v_fma_f32 v21, s4, v13, -v134
-  ; GCN-NEXT:    v_fma_f32 v28, s4, v14, -v134
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[96:111], v[0:1], v[16:17], v[96:111]
   ; GCN-NEXT:    v_mul_f32_e32 v0, 0x3fb8aa3b, v30
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v1, v31
   ; GCN-NEXT:    v_exp_f32_e32 v30, v0
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v1, v31
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v0, v19
   ; GCN-NEXT:    v_pack_b32_f16 v1, v1, v0
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[112:127], v[8:9], v[16:17], v[112:127]
   ; GCN-NEXT:    v_exp_f32_e32 v16, v4
   ; GCN-NEXT:    v_pack_b32_f16 v0, v5, v20
   ; GCN-NEXT:    v_mul_f32_e32 v9, 0x3fb8aa3b, v12
-  ; GCN-NEXT:    v_exp_f32_e32 v18, v9
-  ; GCN-NEXT:    v_mul_f32_e32 v9, 0x3fb8aa3b, v21
-  ; GCN-NEXT:    v_exp_f32_e32 v21, v9
   ; GCN-NEXT:    v_fma_f32 v8, s4, v15, -v134
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v17, v24
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v20, v27
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[6:7], v[0:1], v[64:79]
+  ; GCN-NEXT:    v_exp_f32_e32 v18, v9
+  ; GCN-NEXT:    v_mul_f32_e32 v9, 0x3fb8aa3b, v21
   ; GCN-NEXT:    ds_read_b128 v[4:7], v57
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
   ; GCN-NEXT:    ds_read_b128 v[12:15], v57 offset:576
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v17, v24
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v20, v27
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[80:95], v[22:23], v[0:1], v[80:95]
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v22, v21
+  ; GCN-NEXT:    v_exp_f32_e32 v21, v9
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v23, v18
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v22, v21
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[96:111], v[2:3], v[0:1], v[96:111]
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v3, v30
   ; GCN-NEXT:    v_mul_f32_e32 v2, 0x3fb8aa3b, v28
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v3, v30
   ; GCN-NEXT:    v_exp_f32_e32 v2, v2
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[112:127], v[10:11], v[0:1], v[112:127]
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v0, v16
@@ -1102,29 +1102,30 @@
   ; GCN-NEXT:    v_add_f32_e32 v3, v36, v3
   ; GCN-NEXT:    v_add_f32_e32 v3, v39, v3
   ; GCN-NEXT:    v_add_f32_e32 v3, v148, v3
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[80:95], v[12:13], v[8:9], v[80:95]
   ; GCN-NEXT:    v_add_f32_e32 v3, v34, v3
   ; GCN-NEXT:    v_add_f32_e32 v3, v150, v3
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v1, v10
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v11, v2
   ; GCN-NEXT:    v_add_f32_e32 v3, v38, v3
   ; GCN-NEXT:    v_add_f32_e32 v3, v42, v3
   ; GCN-NEXT:    v_add_f32_e32 v3, v25, v3
   ; GCN-NEXT:    v_add_f32_e32 v3, v26, v3
-  ; GCN-NEXT:    v_pack_b32_f16 v1, v11, v1
-  ; GCN-NEXT:    v_pack_b32_f16 v0, v23, v22
   ; GCN-NEXT:    v_add_f32_e32 v3, v29, v3
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[4:5], v[8:9], v[64:79]
   ; GCN-NEXT:    v_add_f32_e32 v3, v31, v3
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[80:95], v[14:15], v[0:1], v[80:95]
   ; GCN-NEXT:    v_add_f32_e32 v3, v19, v3
   ; GCN-NEXT:    v_add_f32_e32 v3, v24, v3
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v1, v10
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v11, v2
   ; GCN-NEXT:    v_add_f32_e32 v3, v27, v3
   ; GCN-NEXT:    v_add_f32_e32 v3, v30, v3
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[80:95], v[12:13], v[8:9], v[80:95]
   ; GCN-NEXT:    v_add_f32_e32 v3, v16, v3
   ; GCN-NEXT:    v_add_f32_e32 v3, v18, v3
+  ; GCN-NEXT:    v_pack_b32_f16 v1, v11, v1
+  ; GCN-NEXT:    v_pack_b32_f16 v0, v23, v22
   ; GCN-NEXT:    v_add_f32_e32 v3, v21, v3
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[4:5], v[8:9], v[64:79]
+  ; GCN-NEXT:    s_nop 0
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[64:79], v[6:7], v[0:1], v[64:79]
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[80:95], v[14:15], v[0:1], v[80:95]
   ; GCN-NEXT:    v_add_f32_e32 v0, v2, v3
   ; GCN-NEXT:    v_add_f32_e32 v4, v10, v0
   ; GCN-NEXT:    ds_bpermute_b32 v5, v133, v4
diff --git a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.iglp.opt.exp.small.mir b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.iglp.opt.exp.small.mir
index 0887fdf0844b0..4e16ff82f1e60 100644
--- a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.iglp.opt.exp.small.mir
+++ b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.iglp.opt.exp.small.mir
@@ -218,54 +218,48 @@
   ; GCN-NEXT:    v_max_f32_e32 v70, v70, v70
   ; GCN-NEXT:    v_max_f32_e32 v72, v81, v70
   ; GCN-NEXT:    v_fma_f32 v16, s4, v16, -v72
+  ; GCN-NEXT:    v_fma_f32 v17, s4, v17, -v72
   ; GCN-NEXT:    v_fma_f32 v18, s4, v18, -v72
   ; GCN-NEXT:    v_fma_f32 v19, s4, v19, -v72
   ; GCN-NEXT:    v_mul_f32_e32 v16, 0x3fb8aa3b, v16
+  ; GCN-NEXT:    v_mul_f32_e32 v17, 0x3fb8aa3b, v17
   ; GCN-NEXT:    v_mul_f32_e32 v18, 0x3fb8aa3b, v18
   ; GCN-NEXT:    v_mul_f32_e32 v19, 0x3fb8aa3b, v19
-  ; GCN-NEXT:    v_fma_f32 v17, s4, v17, -v72
   ; GCN-NEXT:    v_fma_f32 v20, s4, v20, -v72
   ; GCN-NEXT:    v_fma_f32 v21, s4, v21, -v72
   ; GCN-NEXT:    v_fma_f32 v22, s4, v22, -v72
   ; GCN-NEXT:    v_fma_f32 v23, s4, v23, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v73, v16
+  ; GCN-NEXT:    v_exp_f32_e32 v17, v17
   ; GCN-NEXT:    v_exp_f32_e32 v74, v18
   ; GCN-NEXT:    v_exp_f32_e32 v75, v19
   ; GCN-NEXT:    v_mul_f32_e32 v20, 0x3fb8aa3b, v20
   ; GCN-NEXT:    v_mul_f32_e32 v21, 0x3fb8aa3b, v21
   ; GCN-NEXT:    v_mul_f32_e32 v22, 0x3fb8aa3b, v22
-  ; GCN-NEXT:    v_exp_f32_e32 v80, v20
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v16, v73
   ; GCN-NEXT:    v_fma_f32 v18, s4, v24, -v72
+  ; GCN-NEXT:    v_exp_f32_e32 v80, v20
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v19, v17
+  ; GCN-NEXT:    v_fma_f32 v20, s4, v25, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v81, v21
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v21, v74
-  ; GCN-NEXT:    v_fma_f32 v20, s4, v25, -v72
+  ; GCN-NEXT:    v_fma_f32 v26, s4, v26, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v82, v22
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v22, v75
-  ; GCN-NEXT:    v_mul_f32_e32 v17, 0x3fb8aa3b, v17
   ; GCN-NEXT:    v_mul_f32_e32 v23, 0x3fb8aa3b, v23
-  ; GCN-NEXT:    v_fma_f32 v26, s4, v26, -v72
-  ; GCN-NEXT:    v_pack_b32_f16 v71, v21, v22
-  ; GCN-NEXT:    v_mul_f32_e32 v22, 0x3fb8aa3b, v18
   ; GCN-NEXT:    v_sub_f32_e32 v24, v67, v72
-  ; GCN-NEXT:    v_exp_f32_e32 v83, v23
+  ; GCN-NEXT:    v_pack_b32_f16 v70, v16, v19
+  ; GCN-NEXT:    v_pack_b32_f16 v71, v21, v22
   ; GCN-NEXT:    v_fma_f32 v67, s4, v27, -v72
-  ; GCN-NEXT:    v_exp_f32_e32 v85, v22
-  ; GCN-NEXT:    v_exp_f32_e32 v17, v17
-  ; GCN-NEXT:    v_mul_f32_e32 v24, 0x3fb8aa3b, v24
+  ; GCN-NEXT:    v_exp_f32_e32 v83, v23
+  ; GCN-NEXT:    v_mul_f32_e32 v22, 0x3fb8aa3b, v18
   ; GCN-NEXT:    v_mul_f32_e32 v23, 0x3fb8aa3b, v20
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v19, v17
-  ; GCN-NEXT:    v_fma_f32 v87, s4, v29, -v72
-  ; GCN-NEXT:    v_exp_f32_e32 v88, v23
-  ; GCN-NEXT:    v_fma_f32 v0, s4, v0, -v72
-  ; GCN-NEXT:    v_pack_b32_f16 v70, v16, v19
   ; GCN-NEXT:    ds_read_b128 v[18:21], v84
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
+  ; GCN-NEXT:    v_mul_f32_e32 v24, 0x3fb8aa3b, v24
   ; GCN-NEXT:    v_exp_f32_e32 v16, v24
-  ; GCN-NEXT:    ds_read_b128 v[22:25], v84 offset:576
-  ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
-  ; GCN-NEXT:    buffer_inv sc0 sc1
+  ; GCN-NEXT:    v_perm_b32 v90, v69, v65, s2
   ; GCN-NEXT:    v_pk_mul_f32 v[48:49], v[48:49], v[16:17] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[50:51], v[50:51], v[16:17] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[52:53], v[52:53], v[16:17] op_sel_hi:[1,0]
@@ -276,30 +270,35 @@
   ; GCN-NEXT:    v_pk_mul_f32 v[62:63], v[62:63], v[16:17] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[32:33], v[32:33], v[16:17] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[34:35], v[34:35], v[16:17] op_sel_hi:[1,0]
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[18:19], v[70:71], v[48:63]
+  ; GCN-NEXT:    v_add_f32_e32 v18, 0, v73
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v19, v80
+  ; GCN-NEXT:    v_fma_f32 v73, s4, v28, -v72
+  ; GCN-NEXT:    v_exp_f32_e32 v85, v22
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v86, v81
+  ; GCN-NEXT:    v_fma_f32 v87, s4, v29, -v72
+  ; GCN-NEXT:    v_exp_f32_e32 v88, v23
+  ; GCN-NEXT:    ds_read_b128 v[22:25], v84 offset:576
+  ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
+  ; GCN-NEXT:    buffer_inv sc0 sc1
   ; GCN-NEXT:    v_pk_mul_f32 v[36:37], v[36:37], v[16:17] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[38:39], v[38:39], v[16:17] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[40:41], v[40:41], v[16:17] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[42:43], v[42:43], v[16:17] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[44:45], v[44:45], v[16:17] op_sel_hi:[1,0]
   ; GCN-NEXT:    v_pk_mul_f32 v[46:47], v[46:47], v[16:17] op_sel_hi:[1,0]
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[18:19], v[70:71], v[48:63]
-  ; GCN-NEXT:    v_add_f32_e32 v18, 0, v73
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v89, v83
-  ; GCN-NEXT:    v_fma_f32 v73, s4, v28, -v72
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v19, v80
-  ; GCN-NEXT:    v_fma_f32 v1, s4, v1, -v72
-  ; GCN-NEXT:    v_perm_b32 v90, v69, v65, s2
+  ; GCN-NEXT:    v_perm_b32 v65, v69, v65, s3
+  ; GCN-NEXT:    s_nop 0
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[32:47], v[22:23], v[70:71], v[32:47]
   ; GCN-NEXT:    v_add_f32_e32 v17, v17, v18
   ; GCN-NEXT:    v_mul_f32_e32 v18, 0x3fb8aa3b, v26
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v86, v81
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v22, v82
   ; GCN-NEXT:    v_fma_f32 v23, s4, v30, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v30, v18
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v22, v82
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v89, v83
   ; GCN-NEXT:    v_fma_f32 v18, s4, v31, -v72
   ; GCN-NEXT:    v_perm_b32 v31, v68, v64, s2
   ; GCN-NEXT:    v_perm_b32 v64, v68, v64, s3
-  ; GCN-NEXT:    v_perm_b32 v65, v69, v65, s3
   ; GCN-NEXT:    ds_read_b128 v[26:29], v91
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
@@ -322,31 +321,37 @@
   ; GCN-NEXT:    buffer_wbl2 sc0 sc1
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    ds_write_b32 v78, v90
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[20:21], v[18:19], v[48:63]
   ; GCN-NEXT:    buffer_wbl2 sc0 sc1
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    ds_write_b32 v79, v65
   ; GCN-NEXT:    v_mul_f32_e32 v64, 0x3fb8aa3b, v73
   ; GCN-NEXT:    v_mul_f32_e32 v65, 0x3fb8aa3b, v87
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[20:21], v[18:19], v[48:63]
+  ; GCN-NEXT:    v_mul_f32_e32 v23, 0x3fb8aa3b, v23
   ; GCN-NEXT:    v_add_f32_e32 v17, v74, v17
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v20, v85
-  ; GCN-NEXT:    v_fma_f32 v2, s4, v2, -v72
+  ; GCN-NEXT:    v_fma_f32 v0, s4, v0, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v22, v64
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v21, v88
+  ; GCN-NEXT:    v_fma_f32 v1, s4, v1, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v64, v65
-  ; GCN-NEXT:    v_mul_f32_e32 v23, 0x3fb8aa3b, v23
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[32:47], v[24:25], v[18:19], v[32:47]
   ; GCN-NEXT:    v_add_f32_e32 v17, v75, v17
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v18, v30
-  ; GCN-NEXT:    v_fma_f32 v24, s4, v3, -v72
+  ; GCN-NEXT:    v_fma_f32 v2, s4, v2, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v23, v23
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v19, v31
+  ; GCN-NEXT:    v_fma_f32 v24, s4, v3, -v72
+  ; GCN-NEXT:    v_exp_f32_e32 v25, v67
   ; GCN-NEXT:    v_mul_f32_e32 v3, 0x3fb8aa3b, v0
   ; GCN-NEXT:    v_mul_f32_e32 v65, 0x3fb8aa3b, v1
   ; GCN-NEXT:    v_pack_b32_f16 v0, v20, v21
   ; GCN-NEXT:    v_pack_b32_f16 v1, v18, v19
-  ; GCN-NEXT:    v_fma_f32 v6, s4, v6, -v72
-  ; GCN-NEXT:    v_exp_f32_e32 v25, v67
+  ; GCN-NEXT:    v_mul_f32_e32 v2, 0x3fb8aa3b, v2
+  ; GCN-NEXT:    ;;#ASMSTART
+  ; GCN-NEXT:    s_waitcnt vmcnt(8)
+  ; GCN-NEXT:    ;;#ASMEND
+  ; GCN-NEXT:    v_mul_f32_e32 v24, 0x3fb8aa3b, v24
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[26:27], v[0:1], v[48:63]
   ; GCN-NEXT:    v_add_f32_e32 v17, v80, v17
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v18, v22
@@ -356,62 +361,76 @@
   ; GCN-NEXT:    v_fma_f32 v67, s4, v5, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v65, v65
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[32:47], v[68:69], v[0:1], v[32:47]
-  ; GCN-NEXT:    v_mul_f32_e32 v2, 0x3fb8aa3b, v2
   ; GCN-NEXT:    v_add_f32_e32 v17, v81, v17
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v5, v23
-  ; GCN-NEXT:    v_fma_f32 v7, s4, v7, -v72
+  ; GCN-NEXT:    v_fma_f32 v6, s4, v6, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v68, v2
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v19, v25
-  ; GCN-NEXT:    ;;#ASMSTART
-  ; GCN-NEXT:    s_waitcnt vmcnt(8)
-  ; GCN-NEXT:    ;;#ASMEND
-  ; GCN-NEXT:    v_mul_f32_e32 v24, 0x3fb8aa3b, v24
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    ds_read_b128 v[0:3], v84
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
   ; GCN-NEXT:    v_pack_b32_f16 v4, v18, v4
+  ; GCN-NEXT:    v_fma_f32 v7, s4, v7, -v72
   ; GCN-NEXT:    v_pack_b32_f16 v5, v5, v19
   ; GCN-NEXT:    v_exp_f32_e32 v24, v24
   ; GCN-NEXT:    ds_read_b128 v[18:21], v84 offset:576
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[28:29], v[4:5], v[48:63]
   ; GCN-NEXT:    v_mul_f32_e32 v26, 0x3fb8aa3b, v26
   ; GCN-NEXT:    v_mul_f32_e32 v67, 0x3fb8aa3b, v67
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[28:29], v[4:5], v[48:63]
+  ; GCN-NEXT:    v_mul_f32_e32 v6, 0x3fb8aa3b, v6
   ; GCN-NEXT:    v_add_f32_e32 v17, v82, v17
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v28, v27
+  ; GCN-NEXT:    v_fma_f32 v8, s4, v8, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v26, v26
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v29, v65
-  ; GCN-NEXT:    v_fma_f32 v10, s4, v10, -v72
+  ; GCN-NEXT:    v_fma_f32 v9, s4, v9, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v67, v67
-  ; GCN-NEXT:    v_mul_f32_e32 v6, 0x3fb8aa3b, v6
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[32:47], v[70:71], v[4:5], v[32:47]
   ; GCN-NEXT:    v_add_f32_e32 v17, v83, v17
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v5, v68
+  ; GCN-NEXT:    v_fma_f32 v10, s4, v10, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v6, v6
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v69, v24
   ; GCN-NEXT:    v_mul_f32_e32 v7, 0x3fb8aa3b, v7
+  ; GCN-NEXT:    v_fma_f32 v11, s4, v11, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v7, v7
   ; GCN-NEXT:    v_pack_b32_f16 v4, v28, v29
   ; GCN-NEXT:    v_pack_b32_f16 v5, v5, v69
-  ; GCN-NEXT:    ; implicit-def: $sgpr2
-  ; GCN-NEXT:    s_nop 1
+  ; GCN-NEXT:    v_mul_f32_e32 v8, 0x3fb8aa3b, v8
+  ; GCN-NEXT:    v_mul_f32_e32 v9, 0x3fb8aa3b, v9
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[0:1], v[4:5], v[48:63]
   ; GCN-NEXT:    v_add_f32_e32 v0, v85, v17
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v17, v26
+  ; GCN-NEXT:    v_fma_f32 v12, s4, v12, -v72
+  ; GCN-NEXT:    v_exp_f32_e32 v8, v8
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v28, v67
+  ; GCN-NEXT:    v_fma_f32 v13, s4, v13, -v72
+  ; GCN-NEXT:    v_exp_f32_e32 v9, v9
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[32:47], v[18:19], v[4:5], v[32:47]
   ; GCN-NEXT:    v_add_f32_e32 v4, v88, v0
   ; GCN-NEXT:    v_mul_f32_e32 v0, 0x3fb8aa3b, v10
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v1, v6
+  ; GCN-NEXT:    v_fma_f32 v5, s4, v14, -v72
   ; GCN-NEXT:    v_exp_f32_e32 v10, v0
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v0, v7
+  ; GCN-NEXT:    v_mul_f32_e32 v11, 0x3fb8aa3b, v11
+  ; GCN-NEXT:    v_fma_f32 v14, s4, v15, -v72
+  ; GCN-NEXT:    v_exp_f32_e32 v11, v11
   ; GCN-NEXT:    v_pack_b32_f16 v1, v1, v0
   ; GCN-NEXT:    v_pack_b32_f16 v0, v17, v28
+  ; GCN-NEXT:    ; implicit-def: $sgpr2
   ; GCN-NEXT:    s_nop 1
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[2:3], v[0:1], v[48:63]
+  ; GCN-NEXT:    v_mul_f32_e32 v3, 0x3fb8aa3b, v12
   ; GCN-NEXT:    v_add_f32_e32 v2, v30, v4
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v4, v8
+  ; GCN-NEXT:    v_exp_f32_e32 v12, v3
+  ; GCN-NEXT:    v_mul_f32_e32 v3, 0x3fb8aa3b, v13
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v13, v9
+  ; GCN-NEXT:    v_exp_f32_e32 v15, v3
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[32:47], v[20:21], v[0:1], v[32:47]
   ; GCN-NEXT:    v_add_f32_e32 v0, v31, v2
   ; GCN-NEXT:    v_add_f32_e32 v0, v22, v0
@@ -419,46 +438,27 @@
   ; GCN-NEXT:    v_add_f32_e32 v0, v23, v0
   ; GCN-NEXT:    v_add_f32_e32 v0, v25, v0
   ; GCN-NEXT:    v_add_f32_e32 v0, v27, v0
-  ; GCN-NEXT:    v_fma_f32 v8, s4, v8, -v72
   ; GCN-NEXT:    v_add_f32_e32 v0, v65, v0
-  ; GCN-NEXT:    v_fma_f32 v9, s4, v9, -v72
-  ; GCN-NEXT:    v_mul_f32_e32 v8, 0x3fb8aa3b, v8
   ; GCN-NEXT:    v_add_f32_e32 v0, v68, v0
-  ; GCN-NEXT:    v_fma_f32 v11, s4, v11, -v72
-  ; GCN-NEXT:    v_mul_f32_e32 v9, 0x3fb8aa3b, v9
-  ; GCN-NEXT:    v_fma_f32 v12, s4, v12, -v72
-  ; GCN-NEXT:    v_fma_f32 v13, s4, v13, -v72
-  ; GCN-NEXT:    v_exp_f32_e32 v8, v8
   ; GCN-NEXT:    v_add_f32_e32 v0, v24, v0
-  ; GCN-NEXT:    v_fma_f32 v5, s4, v14, -v72
-  ; GCN-NEXT:    v_exp_f32_e32 v9, v9
   ; GCN-NEXT:    v_add_f32_e32 v0, v26, v0
   ; GCN-NEXT:    v_add_f32_e32 v0, v67, v0
-  ; GCN-NEXT:    v_fma_f32 v14, s4, v15, -v72
-  ; GCN-NEXT:    v_mul_f32_e32 v11, 0x3fb8aa3b, v11
-  ; GCN-NEXT:    v_mul_f32_e32 v3, 0x3fb8aa3b, v12
   ; GCN-NEXT:    v_mul_f32_e32 v1, 0x3fb8aa3b, v5
   ; GCN-NEXT:    v_add_f32_e32 v0, v6, v0
-  ; GCN-NEXT:    v_exp_f32_e32 v11, v11
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v4, v8
-  ; GCN-NEXT:    v_exp_f32_e32 v12, v3
-  ; GCN-NEXT:    v_mul_f32_e32 v3, 0x3fb8aa3b, v13
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v5, v10
   ; GCN-NEXT:    v_exp_f32_e32 v17, v1
   ; GCN-NEXT:    v_mul_f32_e32 v1, 0x3fb8aa3b, v14
   ; GCN-NEXT:    v_add_f32_e32 v0, v7, v0
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v13, v9
-  ; GCN-NEXT:    v_exp_f32_e32 v15, v3
+  ; GCN-NEXT:    v_cvt_f16_f32_e32 v14, v11
   ; GCN-NEXT:    v_exp_f32_e32 v18, v1
   ; GCN-NEXT:    v_add_f32_e32 v6, v8, v0
   ; GCN-NEXT:    ds_read_b128 v[0:3], v91
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    buffer_inv sc0 sc1
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v5, v10
-  ; GCN-NEXT:    v_cvt_f16_f32_e32 v14, v11
   ; GCN-NEXT:    v_add_f32_e32 v6, v9, v6
+  ; GCN-NEXT:    v_pack_b32_f16 v9, v5, v14
   ; GCN-NEXT:    v_pack_b32_f16 v8, v4, v13
   ; GCN-NEXT:    v_add_f32_e32 v6, v10, v6
-  ; GCN-NEXT:    v_pack_b32_f16 v9, v5, v14
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v7, v18
   ; GCN-NEXT:    v_cvt_f16_f32_e32 v10, v15
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[0:1], v[8:9], v[48:63]
@@ -478,13 +478,13 @@
   ; GCN-NEXT:    s_waitcnt vmcnt(8)
   ; GCN-NEXT:    ;;#ASMEND
   ; GCN-NEXT:    v_mov_b32_e32 v4, 0
-  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[32:47], v[6:7], v[0:1], v[32:47]
   ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[48:63], v[2:3], v[0:1], v[48:63]
   ; GCN-NEXT:    v_add_f32_e32 v2, v18, v11
   ; GCN-NEXT:    ds_bpermute_b32 v3, v66, v2
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    v_add_f32_e32 v2, v2, v3
   ; GCN-NEXT:    ds_bpermute_b32 v3, v66, v2
+  ; GCN-NEXT:    v_mfma_f32_32x32x8_f16 v[32:47], v[6:7], v[0:1], v[32:47]
   ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
   ; GCN-NEXT:    v_cndmask_b32_e64 v2, v3, v2, s[0:1]
   ; GCN-NEXT:    v_fmac_f32_e32 v2, v4, v16
diff --git a/llvm/test/CodeGen/AMDGPU/packed-dependencies.mir b/llvm/test/CodeGen/AMDGPU/packed-dependencies.mir
new file mode 100644
index 0000000000000..8d8f31c69b64a
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/packed-dependencies.mir
@@ -0,0 +1,49 @@
+# RUN: llc -mtriple=amdgcn -mcpu=gfx942 -start-before=machine-scheduler -verify-misched -misched-print-dags -o - %s 2>&1 | FileCheck -check-prefix=GCN %s
+
+--- |
+  define amdgpu_kernel void @smallInterleave() { ret void }
+  ; GCN-LABEL: SU(3):   renamable $vgpr0_vgpr1 = contract nofpexcept V_PK_MUL_F32 8, $vgpr2_vgpr3, 0, $vgpr0_vgpr1, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
+  ; GCN-NEXT:   # preds left       : 5
+  ; GCN-NEXT:   # succs left       : 2
+  ; GCN-NEXT:   # rdefs left       : 0
+  ; GCN-NEXT:   Latency            : 1
+  ; GCN-NEXT:   Depth              : 1
+  ; GCN-NEXT:   Height             : 1
+  ; GCN-NEXT:   Predecessors:
+  ; GCN-NEXT:     SU(2): Data Latency=0 Reg=$vgpr2_vgpr3
+  ; GCN-NEXT:     SU(1): Out  Latency=1
+  ; GCN-NEXT:     SU(1): Ord  Latency=0 Artificial
+  ; GCN-NEXT:     SU(0): Out  Latency=1
+  ; GCN-NEXT:     SU(0): Data Latency=1 Reg=$vgpr0_vgpr1
+  ; GCN-NEXT:   Successors:
+  ; GCN-NEXT:     SU(5): Data Latency=1 Reg=$vgpr0_vgpr1
+  ; GCN-NEXT:     SU(4): Anti Latency=0
+
+  ; GCN-LABEL: smallInterleave:
+  ; GCN:       ; %bb.0:
+  ; GCN-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+  ; GCN-NEXT:    v_mov_b32_e32 v0, 0
+  ; GCN-NEXT:    v_mov_b32_e32 v1, 1
+  ; GCN-NEXT:    ; implicit-def: $vgpr2_vgpr3
+  ; GCN-NEXT:    v_pk_mul_f32 v[0:1], v[2:3], v[0:1] op_sel_hi:[1,0]
+  ; GCN-NEXT:    ; implicit-def: $vgpr2_vgpr3
+  ; GCN-NEXT:    buffer_wbl2 sc0 sc1
+  ; GCN-NEXT:    flat_store_dwordx2 v[2:3], v[0:1] sc0 sc1
+  ; GCN-NEXT:    s_endpgm
+...
+
+---
+name:            smallInterleave
+tracksRegLiveness: true
+machineFunctionInfo:
+  stackPtrOffsetReg: '$sgpr32'
+body:             |
+ bb.0:
+  undef %0.sub0:vreg_64_align2 = V_MOV_B32_e32 0, implicit $exec
+  undef %0.sub1:vreg_64_align2 = V_MOV_B32_e32 1, implicit $exec
+  %2:vreg_64_align2 = IMPLICIT_DEF
+  %3:vreg_64_align2 = contract nofpexcept V_PK_MUL_F32 8, %2:vreg_64_align2, 0, %0:vreg_64_align2, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
+  %4:vreg_64_align2 = IMPLICIT_DEF
+  FLAT_STORE_DWORDX2 undef %4:vreg_64_align2, %3:vreg_64_align2, 0, 0, implicit $exec, implicit $flat_scr
+  S_ENDPGM 0
+...

>From bdc9ac065dfac8f12fe01eb2870d1f1ff772dda6 Mon Sep 17 00:00:00 2001
From: Robert Imschweiler <robert.imschweiler at amd.com>
Date: Fri, 16 May 2025 14:27:34 -0500
Subject: [PATCH 2/2] implement feedback part 1

---
 llvm/lib/Target/AMDGPU/GCNSubtarget.cpp       | 19 ++++--
 llvm/lib/Target/AMDGPU/GCNSubtarget.h         | 11 +---
 .../CodeGen/AMDGPU/packed-dependencies.mir    | 58 +++++++------------
 3 files changed, 38 insertions(+), 50 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp b/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp
index 843aca57be2bf..1c43e3e65370b 100644
--- a/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNSubtarget.cpp
@@ -538,11 +538,23 @@ unsigned GCNSubtarget::getMaxNumVGPRs(const MachineFunction &MF) const {
 bool GCNSubtarget::isRealSchedDependency(MachineInstr *DefI, int DefOpIdx,
                                          MachineInstr *UseI,
                                          int UseOpIdx) const {
+  // From the (gfx942, for example) ISA:
+  // "Packed 32-bit instructions operate on 2 dwords at a time and those
+  // operands must be two-dword aligned (i.e. an even VGPR address). Output
+  // modifiers are not supported for these instructions. OPSEL and OPSEL_HI work
+  // to select the first or second DWORD for each source."
+  // -> We can save dependencies on VGPRs by analyzing the operand selection.
+  // See also
+  // https://llvm.org/docs/AMDGPUModifierSyntax.html#amdgpu-synid-op-sel
+
   if (!InstrInfo.isVOP3P(*UseI))
     return true;
   MachineOperand &DefOp = DefI->getOperand(DefOpIdx);
   if (!DefOp.isReg() || !DefOp.getReg().isPhysical())
     return true;
+  MachineOperand &UseOp = UseI->getOperand(UseOpIdx);
+  if (!UseOp.isReg() || !UseOp.getReg().isPhysical())
+    return true;
 
   AMDGPU::OpName UseModName;
   if (AMDGPU::getNamedOperandIdx(UseI->getOpcode(), AMDGPU::OpName::src0) ==
@@ -561,14 +573,11 @@ bool GCNSubtarget::isRealSchedDependency(MachineInstr *DefI, int DefOpIdx,
     return true;
   // Check whether all parts of the register are being used (= op_sel and
   // op_sel_hi differ). In that case we can return early.
-  auto OpSel = UseOpMod->getImm() & SISrcMods::OP_SEL_0;
-  auto OpSelHi = UseOpMod->getImm() & SISrcMods::OP_SEL_1;
+  int64_t OpSel = UseOpMod->getImm() & SISrcMods::OP_SEL_0;
+  int64_t OpSelHi = UseOpMod->getImm() & SISrcMods::OP_SEL_1;
   if ((!OpSel || !OpSelHi) && (OpSel || OpSelHi))
     return true;
 
-  MachineOperand &UseOp = UseI->getOperand(UseOpIdx);
-  if (!UseOp.isReg() || !UseOp.getReg().isPhysical())
-    return true;
   const SIRegisterInfo *TRI = getRegisterInfo();
   const MachineRegisterInfo &MRI = UseI->getParent()->getParent()->getRegInfo();
   MCRegister DefReg = DefOp.getReg().asMCReg();
diff --git a/llvm/lib/Target/AMDGPU/GCNSubtarget.h b/llvm/lib/Target/AMDGPU/GCNSubtarget.h
index edee53a53a2d0..0c4eb8649c6de 100644
--- a/llvm/lib/Target/AMDGPU/GCNSubtarget.h
+++ b/llvm/lib/Target/AMDGPU/GCNSubtarget.h
@@ -272,14 +272,9 @@ class GCNSubtarget final : public AMDGPUGenSubtargetInfo,
   SITargetLowering TLInfo;
   SIFrameLowering FrameLowering;
 
-  /// From the (MI300) ISA:
-  /// "Packed 32-bit instructions operate on 2 dwords at a time and those
-  /// operands must be two-dword aligned (i.e. an even VGPR address). Output
-  /// modifiers are not supported for these instructions. OPSEL and OPSEL_HI
-  /// work to select the first or second DWORD for each source."
-  /// -> We can save dependencies on VGPRs by analyzing the operand selection.
-  /// See also
-  /// https://llvm.org/docs/AMDGPUModifierSyntax.html#amdgpu-synid-op-sel
+  /// Check whether there is a real dependency between the definition and the
+  /// use.  The definition might only affect a subregister that is not actually
+  /// used.
   bool isRealSchedDependency(MachineInstr *DefI, int DefOpIdx,
                              MachineInstr *UseI, int UseOpIdx) const;
 
diff --git a/llvm/test/CodeGen/AMDGPU/packed-dependencies.mir b/llvm/test/CodeGen/AMDGPU/packed-dependencies.mir
index 8d8f31c69b64a..f2b088b8c108d 100644
--- a/llvm/test/CodeGen/AMDGPU/packed-dependencies.mir
+++ b/llvm/test/CodeGen/AMDGPU/packed-dependencies.mir
@@ -1,49 +1,33 @@
-# RUN: llc -mtriple=amdgcn -mcpu=gfx942 -start-before=machine-scheduler -verify-misched -misched-print-dags -o - %s 2>&1 | FileCheck -check-prefix=GCN %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx942 -start-before=machine-scheduler -verify-misched -misched-print-dags -stop-after=machine-scheduler -filetype=null %s 2>&1 | FileCheck -check-prefix=GCN %s
 
 --- |
-  define amdgpu_kernel void @smallInterleave() { ret void }
-  ; GCN-LABEL: SU(3):   renamable $vgpr0_vgpr1 = contract nofpexcept V_PK_MUL_F32 8, $vgpr2_vgpr3, 0, $vgpr0_vgpr1, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
-  ; GCN-NEXT:   # preds left       : 5
-  ; GCN-NEXT:   # succs left       : 2
-  ; GCN-NEXT:   # rdefs left       : 0
-  ; GCN-NEXT:   Latency            : 1
-  ; GCN-NEXT:   Depth              : 1
-  ; GCN-NEXT:   Height             : 1
-  ; GCN-NEXT:   Predecessors:
-  ; GCN-NEXT:     SU(2): Data Latency=0 Reg=$vgpr2_vgpr3
-  ; GCN-NEXT:     SU(1): Out  Latency=1
-  ; GCN-NEXT:     SU(1): Ord  Latency=0 Artificial
-  ; GCN-NEXT:     SU(0): Out  Latency=1
-  ; GCN-NEXT:     SU(0): Data Latency=1 Reg=$vgpr0_vgpr1
-  ; GCN-NEXT:   Successors:
-  ; GCN-NEXT:     SU(5): Data Latency=1 Reg=$vgpr0_vgpr1
-  ; GCN-NEXT:     SU(4): Anti Latency=0
-
-  ; GCN-LABEL: smallInterleave:
-  ; GCN:       ; %bb.0:
-  ; GCN-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-  ; GCN-NEXT:    v_mov_b32_e32 v0, 0
-  ; GCN-NEXT:    v_mov_b32_e32 v1, 1
-  ; GCN-NEXT:    ; implicit-def: $vgpr2_vgpr3
-  ; GCN-NEXT:    v_pk_mul_f32 v[0:1], v[2:3], v[0:1] op_sel_hi:[1,0]
-  ; GCN-NEXT:    ; implicit-def: $vgpr2_vgpr3
-  ; GCN-NEXT:    buffer_wbl2 sc0 sc1
-  ; GCN-NEXT:    flat_store_dwordx2 v[2:3], v[0:1] sc0 sc1
-  ; GCN-NEXT:    s_endpgm
+  define amdgpu_kernel void @check_subreg_dep() { ret void }
+  ; GCN-LABEL: SU(2):   $vgpr0_vgpr1 = contract nofpexcept V_PK_MUL_F32 8, undef $vgpr2_vgpr3, 0, $vgpr0_vgpr1, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
+  ; GCN-NEXT:    # preds left       : 4
+  ; GCN-NEXT:    # succs left       : 1
+  ; GCN-NEXT:    # rdefs left       : 0
+  ; GCN-NEXT:    Latency            : 1
+  ; GCN-NEXT:    Depth              : 1
+  ; GCN-NEXT:    Height             : 1
+  ; GCN-NEXT:    Predecessors:
+  ; GCN-NEXT:      SU(1): Out  Latency=1
+  ; GCN-NEXT:      SU(1): Ord  Latency=0 Artificial
+  ; GCN-NEXT:      SU(0): Out  Latency=1
+  ; GCN-NEXT:      SU(0): Data Latency=1 Reg=$vgpr0_vgpr1
+  ; GCN-NEXT:    Successors:
+  ; GCN-NEXT:      SU(3): Data Latency=1 Reg=$vgpr0_vgpr1
 ...
 
 ---
-name:            smallInterleave
+name:            check_subreg_dep
 tracksRegLiveness: true
 machineFunctionInfo:
   stackPtrOffsetReg: '$sgpr32'
 body:             |
  bb.0:
-  undef %0.sub0:vreg_64_align2 = V_MOV_B32_e32 0, implicit $exec
-  undef %0.sub1:vreg_64_align2 = V_MOV_B32_e32 1, implicit $exec
-  %2:vreg_64_align2 = IMPLICIT_DEF
-  %3:vreg_64_align2 = contract nofpexcept V_PK_MUL_F32 8, %2:vreg_64_align2, 0, %0:vreg_64_align2, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
-  %4:vreg_64_align2 = IMPLICIT_DEF
-  FLAT_STORE_DWORDX2 undef %4:vreg_64_align2, %3:vreg_64_align2, 0, 0, implicit $exec, implicit $flat_scr
+  $vgpr0 = V_MOV_B32_e32 0, implicit $exec
+  $vgpr1 = V_MOV_B32_e32 1, implicit $exec
+  $vgpr0_vgpr1 = contract nofpexcept V_PK_MUL_F32 8, undef $vgpr2_vgpr3, 0, $vgpr0_vgpr1, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
+  FLAT_STORE_DWORDX2 undef $vgpr2_vgpr3, $vgpr0_vgpr1, 0, 0, implicit $exec, implicit $flat_scr
   S_ENDPGM 0
 ...



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