[llvm] [AMDGPU][MC] Allow op_sel in v_alignbit_b32 etc in GFX9 and GFX10 (PR #142188)

Jun Wang via llvm-commits llvm-commits at lists.llvm.org
Tue Jul 8 15:52:02 PDT 2025


https://github.com/jwanggit86 updated https://github.com/llvm/llvm-project/pull/142188

>From 2306384dd79070d3ff5ff051509213fd0745ed1b Mon Sep 17 00:00:00 2001
From: Jun Wang <jwang86 at yahoo.com>
Date: Fri, 23 May 2025 12:31:41 -0700
Subject: [PATCH 1/5] [AMDGPU][MC] Allow op_sel in v_alignbit_b32 etc in GFX9
 and GFX10

In GFX9 and GFX10, the op_sel modifier should be allowed in the
instructions v_align_bit_b32 and v_alignbyte_b32.
---
 llvm/lib/Target/AMDGPU/VOP3Instructions.td | 22 ++++++++++++++++++++
 llvm/test/MC/AMDGPU/gfx10_asm_vop3.s       | 24 ++++++++++++++++++++++
 llvm/test/MC/AMDGPU/gfx7_err_pos.s         | 13 ++++++++++++
 llvm/test/MC/AMDGPU/gfx8_err_pos.s         | 10 +++++++++
 llvm/test/MC/AMDGPU/gfx9_asm_vop3_e64.s    | 24 ++++++++++++++++++++++
 5 files changed, 93 insertions(+)

diff --git a/llvm/lib/Target/AMDGPU/VOP3Instructions.td b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
index aa7578a29faed..789088e493cac 100644
--- a/llvm/lib/Target/AMDGPU/VOP3Instructions.td
+++ b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
@@ -222,6 +222,11 @@ defm V_ALIGNBIT_B32 : VOP3Inst_t16_with_profiles <"v_alignbit_b32",
                                                    fshr, null_frag>;
 
 defm V_ALIGNBYTE_B32 : VOP3Inst <"v_alignbyte_b32", VOP3_Profile<VOP_I32_I32_I32_I32>, int_amdgcn_alignbyte>;
+
+// In gfx9 and 10, opsel is allowed for V_ALIGNBIT_B32 and V_ALIGNBYTE_B32
+defm V_ALIGNBIT_B32_opsel : VOP3Inst <"v_alignbit_b32_opsel", VOP3_Profile<VOP_I32_I32_I32_I32, VOP3_OPSEL>>;
+defm V_ALIGNBYTE_B32_opsel : VOP3Inst <"v_alignbyte_b32_opsel", VOP3_Profile<VOP_I32_I32_I32_I32, VOP3_OPSEL>>;
+
 let True16Predicate = UseRealTrue16Insts in
 defm V_ALIGNBYTE_B32_t16 : VOP3Inst <"v_alignbyte_b32_t16", VOP3_Profile_True16<VOP_I32_I32_I32_I16, VOP3_OPSEL>>;
 let True16Predicate = UseFakeTrue16Insts in
@@ -1947,6 +1952,9 @@ let AssemblerPredicate = isGFX10Only, DecoderNamespace = "GFX10" in {
   }
 } // End AssemblerPredicate = isGFX10Only, DecoderNamespace = "GFX10"
 
+defm V_ALIGNBIT_B32_opsel  : VOP3OpSel_Real_gfx10_with_name<0x14e, "V_ALIGNBIT_B32_opsel", "v_alignbit_b32">;
+defm V_ALIGNBYTE_B32_opsel  : VOP3OpSel_Real_gfx10_with_name<0x14f, "V_ALIGNBYTE_B32_opsel", "v_alignbyte_b32">;
+
 defm V_READLANE_B32  : VOP3_Real_No_Suffix_gfx10<0x360>;
 
 let InOperandList = (ins SSrcOrLds_b32:$src0, SCSrc_b32:$src1, VGPR_32:$vdst_in) in {
@@ -2241,6 +2249,17 @@ multiclass VOP3_Real_BITOP3_gfx9<bits<10> op, string AsmName, bit isSingle = 0>
   }
 }
 
+// Instructions such as v_alignbyte_b32 allows op_sel in gfx9, but not in vi.
+// The following is created to support that.
+multiclass VOP3OpSel_Real_gfx9_with_names<bits<10> op, string opName, string AsmName> {
+  defvar psName = opName#"_e64";
+  def _gfx9 : VOP3_Real<!cast<VOP3_Pseudo>(psName), SIEncodingFamily.VI>, // note: encoding family is VI
+            VOP3OpSel_gfx9 <op, !cast<VOP3_Pseudo>(psName).Pfl> {
+              VOP3_Pseudo ps = !cast<VOP3_Pseudo>(psName);
+              let AsmString = AsmName # ps.AsmOperands;
+            }
+}
+
 } // End AssemblerPredicate = isGFX9Only, DecoderNamespace = "GFX9"
 
 defm V_MAD_U64_U32      : VOP3be_Real_vi <0x1E8>;
@@ -2306,6 +2325,9 @@ defm V_INTERP_P2_LEGACY_F16 : VOP3Interp_F16_Real_gfx9 <0x276, "V_INTERP_P2_F16"
 defm V_MAD_LEGACY_U16       : VOP3_F16_Real_gfx9 <0x1eb, "V_MAD_U16",       "v_mad_legacy_u16">;
 defm V_MAD_LEGACY_I16       : VOP3_F16_Real_gfx9 <0x1ec, "V_MAD_I16",       "v_mad_legacy_i16">;
 
+defm V_ALIGNBIT_B32_opsel   : VOP3OpSel_Real_gfx9_with_names <0x1ce, "V_ALIGNBIT_B32_opsel", "v_alignbit_b32">;
+defm V_ALIGNBYTE_B32_opsel  : VOP3OpSel_Real_gfx9_with_names <0x1cf, "V_ALIGNBYTE_B32_opsel", "v_alignbyte_b32">;
+
 defm V_MAD_F16_gfx9         : VOP3OpSel_F16_Real_gfx9 <0x203, "v_mad_f16">;
 defm V_MAD_U16_gfx9         : VOP3OpSel_F16_Real_gfx9 <0x204, "v_mad_u16">;
 defm V_MAD_I16_gfx9         : VOP3OpSel_F16_Real_gfx9 <0x205, "v_mad_i16">;
diff --git a/llvm/test/MC/AMDGPU/gfx10_asm_vop3.s b/llvm/test/MC/AMDGPU/gfx10_asm_vop3.s
index 6bb0f4b1dff2d..3d6af6ba6dbf8 100644
--- a/llvm/test/MC/AMDGPU/gfx10_asm_vop3.s
+++ b/llvm/test/MC/AMDGPU/gfx10_asm_vop3.s
@@ -3628,6 +3628,18 @@ v_alignbit_b32 v5, v1, v2, exec_lo
 v_alignbit_b32 v5, v1, v2, exec_hi
 // GFX10: encoding: [0x05,0x00,0x4e,0xd5,0x01,0x05,0xfe,0x01]
 
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1]
+// GFX10: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,0,0,0] ; encoding: [0x05,0x08,0x4e,0xd5,0x01,0x05,0x0e,0x04]
+
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1]
+// GFX10: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,0,0] ; encoding: [0x05,0x18,0x4e,0xd5,0x01,0x05,0x0e,0x04]
+
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1]
+// GFX10: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,0] ; encoding: [0x05,0x38,0x4e,0xd5,0x01,0x05,0x0e,0x04]
+
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// GFX10: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,1] ; encoding: [0x05,0x78,0x4e,0xd5,0x01,0x05,0x0e,0x04]
+
 v_alignbyte_b32 v5, v1, v2, v3
 // GFX10: encoding: [0x05,0x00,0x4f,0xd5,0x01,0x05,0x0e,0x04]
 
@@ -3715,6 +3727,18 @@ v_alignbyte_b32 v5, v1, v2, exec_lo
 v_alignbyte_b32 v5, v1, v2, exec_hi
 // GFX10: encoding: [0x05,0x00,0x4f,0xd5,0x01,0x05,0xfe,0x01]
 
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1]
+// GFX10: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,0,0,0] ; encoding: [0x05,0x08,0x4f,0xd5,0x01,0x05,0x0e,0x04]
+
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1]
+// GFX10: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,0,0] ; encoding: [0x05,0x18,0x4f,0xd5,0x01,0x05,0x0e,0x04]
+
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1]
+// GFX10: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,0] ; encoding: [0x05,0x38,0x4f,0xd5,0x01,0x05,0x0e,0x04]
+
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// GFX10: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1] ; encoding: [0x05,0x78,0x4f,0xd5,0x01,0x05,0x0e,0x04]
+
 v_mullit_f32 v5, v1, v2, v3
 // GFX10: encoding: [0x05,0x00,0x50,0xd5,0x01,0x05,0x0e,0x04]
 
diff --git a/llvm/test/MC/AMDGPU/gfx7_err_pos.s b/llvm/test/MC/AMDGPU/gfx7_err_pos.s
index 9dcbd4a4074af..7b6b241e04707 100644
--- a/llvm/test/MC/AMDGPU/gfx7_err_pos.s
+++ b/llvm/test/MC/AMDGPU/gfx7_err_pos.s
@@ -44,3 +44,16 @@ s_load_dword s5, s[2:3], glc
 // CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: cache policy is not supported for SMRD instructions
 // CHECK-NEXT:{{^}}s_load_dword s5, s[2:3], glc
 // CHECK-NEXT:{{^}}                         ^
+
+//==============================================================================
+// not a valid operand
+
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: not a valid operand.
+// CHECK-NEXT:{{^}}v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// CHECK-NEXT:{{^}}                              ^
+
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: not a valid operand.
+// CHECK-NEXT:{{^}}v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// CHECK-NEXT:{{^}}                               ^
diff --git a/llvm/test/MC/AMDGPU/gfx8_err_pos.s b/llvm/test/MC/AMDGPU/gfx8_err_pos.s
index 1e8457d54049a..a475c739e690d 100644
--- a/llvm/test/MC/AMDGPU/gfx8_err_pos.s
+++ b/llvm/test/MC/AMDGPU/gfx8_err_pos.s
@@ -49,3 +49,13 @@ v_cndmask_b32_sdwa v5, v1, sext(v2), vcc dst_sel:DWORD dst_unused:UNUSED_PRESERV
 // CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: not a valid operand.
 // CHECK-NEXT:{{^}}v_cndmask_b32_sdwa v5, v1, sext(v2), vcc dst_sel:DWORD dst_unused:UNUSED_PRESERVE src0_sel:BYTE_0 src1_sel:WORD_0
 // CHECK-NEXT:{{^}}                           ^
+
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: not a valid operand.
+// CHECK-NEXT:{{^}}v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// CHECK-NEXT:{{^}}                              ^
+
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// CHECK: :[[@LINE-1]]:{{[0-9]+}}: error: not a valid operand.
+// CHECK-NEXT:{{^}}v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// CHECK-NEXT:{{^}}                               ^
diff --git a/llvm/test/MC/AMDGPU/gfx9_asm_vop3_e64.s b/llvm/test/MC/AMDGPU/gfx9_asm_vop3_e64.s
index f3f4cae22538a..a1cd9ce8ef18e 100644
--- a/llvm/test/MC/AMDGPU/gfx9_asm_vop3_e64.s
+++ b/llvm/test/MC/AMDGPU/gfx9_asm_vop3_e64.s
@@ -2829,6 +2829,18 @@ v_alignbit_b32 v5, v1, v2, src_execz
 v_alignbit_b32 v5, v1, v2, src_scc
 // CHECK: [0x05,0x00,0xce,0xd1,0x01,0x05,0xf6,0x03]
 
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,0,0,0] ; encoding: [0x05,0x08,0xce,0xd1,0x01,0x05,0x0e,0x04]
+// CHECK: [0x05,0x08,0xce,0xd1,0x01,0x05,0x0e,0x04]
+
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,0,0] ; encoding: [0x05,0x18,0xce,0xd1,0x01,0x05,0x0e,0x04]
+// CHECK: [0x05,0x18,0xce,0xd1,0x01,0x05,0x0e,0x04]
+
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,0] ; encoding: [0x05,0x38,0xce,0xd1,0x01,0x05,0x0e,0x04]
+// CHECK: [0x05,0x38,0xce,0xd1,0x01,0x05,0x0e,0x04]
+
+v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,1] ; encoding: [0x05,0x78,0xce,0xd1,0x01,0x05,0x0e,0x04]
+// CHECK: [0x05,0x78,0xce,0xd1,0x01,0x05,0x0e,0x04]
+
 v_alignbyte_b32 v5, v1, v2, v3
 // CHECK: [0x05,0x00,0xcf,0xd1,0x01,0x05,0x0e,0x04]
 
@@ -3000,6 +3012,18 @@ v_alignbyte_b32 v5, v1, v2, src_execz
 v_alignbyte_b32 v5, v1, v2, src_scc
 // CHECK: [0x05,0x00,0xcf,0xd1,0x01,0x05,0xf6,0x03]
 
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1]
+// CHECK: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,0,0,0] ; encoding: [0x05,0x08,0xcf,0xd1,0x01,0x05,0x0e,0x04]
+
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1]
+// CHECK: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,0,0] ; encoding: [0x05,0x18,0xcf,0xd1,0x01,0x05,0x0e,0x04]
+
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1]
+// CHECK: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,0] ; encoding: [0x05,0x38,0xcf,0xd1,0x01,0x05,0x0e,0x04]
+
+v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1]
+// CHECK: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1] ; encoding: [0x05,0x78,0xcf,0xd1,0x01,0x05,0x0e,0x04]
+
 v_min3_f32 v5, v1, v2, v3
 // CHECK: [0x05,0x00,0xd0,0xd1,0x01,0x05,0x0e,0x04]
 

>From 9b6f8a263a0115c665d32c58db991697de4b7653 Mon Sep 17 00:00:00 2001
From: Jun Wang <jwang86 at yahoo.com>
Date: Wed, 2 Jul 2025 16:21:37 -0700
Subject: [PATCH 2/5] Futher changes to tableGen to ensure disassembler works.

---
 llvm/lib/Target/AMDGPU/SIInstructions.td      | 93 ++++++++++++++++++-
 llvm/lib/Target/AMDGPU/VOP3Instructions.td    |  9 +-
 .../AMDGPU/GlobalISel/inst-select-fshr.mir    | 22 ++++-
 .../branch-folding-implicit-def-subreg.ll     |  6 +-
 .../MC/Disassembler/AMDGPU/gfx10_vop3.txt     | 24 +++++
 .../test/MC/Disassembler/AMDGPU/gfx9_vop3.txt | 24 +++++
 6 files changed, 165 insertions(+), 13 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/SIInstructions.td b/llvm/lib/Target/AMDGPU/SIInstructions.td
index 5694d72751f84..760c78f57610b 100644
--- a/llvm/lib/Target/AMDGPU/SIInstructions.td
+++ b/llvm/lib/Target/AMDGPU/SIInstructions.td
@@ -2465,6 +2465,7 @@ def : AMDGPUPat <
 >;
 
 let True16Predicate = NotHasTrue16BitInsts in {
+let SubtargetPredicate = isNotGFX9Plus in {
 def : ROTRPattern <V_ALIGNBIT_B32_e64>;
 
 def : GCNPat<(i32 (trunc (srl i64:$src0, (and i32:$src1, (i32 31))))),
@@ -2474,6 +2475,62 @@ def : GCNPat<(i32 (trunc (srl i64:$src0, (and i32:$src1, (i32 31))))),
 def : GCNPat<(i32 (trunc (srl i64:$src0, (i32 ShiftAmt32Imm:$src1)))),
           (V_ALIGNBIT_B32_e64 (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),
                           (i32 (EXTRACT_SUBREG (i64 $src0), sub0)), $src1)>;
+} // isNotGFX9Plus
+
+let SubtargetPredicate = isGFX9GFX10 in {
+def : GCNPat <
+        (rotr i32:$src0, i32:$src1),
+        (V_ALIGNBIT_B32_opsel_e64 /* src0_modifiers */ 0, $src0,
+                                  /* src1_modifiers */ 0, $src0,
+                                  /* src2_modifiers */ 0,
+                                  $src1, /* clamp */ 0, /* op_sel */ 0)
+>;
+
+foreach pat = [(i32 (trunc (srl i64:$src0, (and i32:$src1, (i32 31))))),
+               (i32 (trunc (srl i64:$src0, (i32 ShiftAmt32Imm:$src1))))] in
+def : GCNPat<pat,
+        (V_ALIGNBIT_B32_opsel_e64 0, /* src0_modifiers */
+                                  (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),
+                                  0, /* src1_modifiers */
+                                  (i32 (EXTRACT_SUBREG (i64 $src0), sub0)),
+                                  0, /* src2_modifiers */
+                                  $src1, /* clamp */ 0, /* op_sel */ 0)
+>;
+
+//def : GCNPat<(i32 (trunc (srl i64:$src0, (and i32:$src1, (i32 31))))),
+//     (V_ALIGNBIT_B32_opsel_e64 0, /* src0_modifiers */
+//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),
+//                                0, /* src1_modifiers */
+//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub0)),
+//                                0, /* src2_modifiers */
+//                                $src1, /* clamp */ 0, /* op_sel */ 0)
+//>;
+
+//def : GCNPat<(i32 (trunc (srl i64:$src0, (and i32:$src1, (i32 31))))),
+//     (V_ALIGNBIT_B32_opsel_e64 0, /* src0_modifiers */
+//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),
+//                                0, /* src1_modifiers */
+//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub0)),
+//                                0, /* src2_modifiers */
+//                                $src1, /* clamp */ 0, /* op_sel */ 0)
+//>;
+
+//def : GCNPat<(i32 (trunc (srl i64:$src0, (i32 ShiftAmt32Imm:$src1)))),
+//     (V_ALIGNBIT_B32_opsel_e64 0, /* src0_modifiers */
+//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),
+//                                0, /* src1_modifiers */
+//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub0)),
+//                                0, /* src2_modifiers */
+//                                $src1, /* clamp */ 0, /* op_sel */ 0)
+//>;
+
+def : GCNPat<(fshr i32:$src0, i32:$src1, i32:$src2),
+        (V_ALIGNBIT_B32_opsel_e64 /* src0_modifiers */ 0, $src0,
+                                  /* src1_modifiers */ 0, $src1,
+                                  /* src2_modifiers */ 0,
+                                  $src2, /* clamp */ 0, /* op_sel */ 0)
+>;
+} // isGFX9GFX10
 } // end True16Predicate = NotHasTrue16BitInsts
 
 let True16Predicate = UseRealTrue16Insts in {
@@ -3549,15 +3606,41 @@ def : GCNPat <
 
 // Take the upper 16 bits from V[0] and the lower 16 bits from V[1]
 // Special case, can use V_ALIGNBIT (always uses encoded literal)
-let True16Predicate = NotHasTrue16BitInsts in
-def : GCNPat <
+let True16Predicate = NotHasTrue16BitInsts in {
+
+defvar BuildVectorToAlignBitPat =
   (vecTy (DivergentBinFrag<build_vector>
     (Ty !if(!eq(Ty, i16),
       (Ty (trunc (srl VGPR_32:$a, (i32 16)))),
       (Ty (bitconvert (i16 (trunc (srl VGPR_32:$a, (i32 16)))))))),
-    (Ty VGPR_32:$b))),
-    (V_ALIGNBIT_B32_e64 VGPR_32:$b, VGPR_32:$a, (i32 16))
->;
+    (Ty VGPR_32:$b)));
+
+let SubtargetPredicate = isNotGFX9Plus in
+def : GCNPat<BuildVectorToAlignBitPat, (V_ALIGNBIT_B32_e64 VGPR_32:$b, VGPR_32:$a, (i32 16))>;
+
+let SubtargetPredicate = isGFX9GFX10 in
+def : GCNPat<BuildVectorToAlignBitPat, (V_ALIGNBIT_B32_opsel_e64 0, VGPR_32:$b, 0, VGPR_32:$a, 0, (i32 16), 0, 0)>;
+
+//let SubtargetPredicate = isNotGFX9Plus in
+//def : GCNPat <
+//  (vecTy (DivergentBinFrag<build_vector>
+//    (Ty !if(!eq(Ty, i16),
+//      (Ty (trunc (srl VGPR_32:$a, (i32 16)))),
+//      (Ty (bitconvert (i16 (trunc (srl VGPR_32:$a, (i32 16)))))))),
+//    (Ty VGPR_32:$b))),
+//    (V_ALIGNBIT_B32_e64 VGPR_32:$b, VGPR_32:$a, (i32 16))
+//>;
+
+//let SubtargetPredicate = isGFX9GFX10 in
+//def : GCNPat <
+//  (vecTy (DivergentBinFrag<build_vector>
+//    (Ty !if(!eq(Ty, i16),
+//      (Ty (trunc (srl VGPR_32:$a, (i32 16)))),
+//      (Ty (bitconvert (i16 (trunc (srl VGPR_32:$a, (i32 16)))))))),
+//    (Ty VGPR_32:$b))),
+//    (V_ALIGNBIT_B32_opsel_e64 0, VGPR_32:$b, 0, VGPR_32:$a, 0, (i32 16), 0, 0)
+//>;
+} //True16Predicate = NotHasTrue16BitInsts
 
 let True16Predicate = UseFakeTrue16Insts in
 def : GCNPat <
diff --git a/llvm/lib/Target/AMDGPU/VOP3Instructions.td b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
index 789088e493cac..2609c9758d8bc 100644
--- a/llvm/lib/Target/AMDGPU/VOP3Instructions.td
+++ b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
@@ -223,7 +223,8 @@ defm V_ALIGNBIT_B32 : VOP3Inst_t16_with_profiles <"v_alignbit_b32",
 
 defm V_ALIGNBYTE_B32 : VOP3Inst <"v_alignbyte_b32", VOP3_Profile<VOP_I32_I32_I32_I32>, int_amdgcn_alignbyte>;
 
-// In gfx9 and 10, opsel is allowed for V_ALIGNBIT_B32 and V_ALIGNBYTE_B32
+// In gfx9 and 10, opsel is allowed for V_ALIGNBIT_B32 and V_ALIGNBYTE_B32.
+// Hardware uses opsel[1:0] to byte-select src2. Other opsel bits are ignored.
 defm V_ALIGNBIT_B32_opsel : VOP3Inst <"v_alignbit_b32_opsel", VOP3_Profile<VOP_I32_I32_I32_I32, VOP3_OPSEL>>;
 defm V_ALIGNBYTE_B32_opsel : VOP3Inst <"v_alignbyte_b32_opsel", VOP3_Profile<VOP_I32_I32_I32_I32, VOP3_OPSEL>>;
 
@@ -2105,8 +2106,8 @@ defm V_BFI_B32         : VOP3_Real_gfx6_gfx7_gfx10<0x14a>;
 defm V_FMA_F32         : VOP3_Real_gfx6_gfx7_gfx10<0x14b>;
 defm V_FMA_F64         : VOP3_Real_gfx6_gfx7_gfx10<0x14c>;
 defm V_LERP_U8         : VOP3_Real_gfx6_gfx7_gfx10<0x14d>;
-defm V_ALIGNBIT_B32    : VOP3_Real_gfx6_gfx7_gfx10<0x14e>;
-defm V_ALIGNBYTE_B32   : VOP3_Real_gfx6_gfx7_gfx10<0x14f>;
+defm V_ALIGNBIT_B32    : VOP3_Real_gfx6_gfx7<0x14e>;
+defm V_ALIGNBYTE_B32   : VOP3_Real_gfx6_gfx7<0x14f>;
 defm V_MULLIT_F32      : VOP3_Real_gfx6_gfx7_gfx10<0x150>;
 defm V_MIN3_F32        : VOP3_Real_gfx6_gfx7_gfx10<0x151>;
 defm V_MIN3_I32        : VOP3_Real_gfx6_gfx7_gfx10<0x152>;
@@ -2279,8 +2280,10 @@ defm V_BFI_B32          : VOP3_Real_vi <0x1ca>;
 defm V_FMA_F32          : VOP3_Real_vi <0x1cb>;
 defm V_FMA_F64          : VOP3_Real_vi <0x1cc>;
 defm V_LERP_U8          : VOP3_Real_vi <0x1cd>;
+let SubtargetPredicate = isGFX8Only in {
 defm V_ALIGNBIT_B32     : VOP3_Real_vi <0x1ce>;
 defm V_ALIGNBYTE_B32    : VOP3_Real_vi <0x1cf>;
+}
 defm V_MIN3_F32         : VOP3_Real_vi <0x1d0>;
 defm V_MIN3_I32         : VOP3_Real_vi <0x1d1>;
 defm V_MIN3_U32         : VOP3_Real_vi <0x1d2>;
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-fshr.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-fshr.mir
index 0a4cb3ccf2957..fa95f33909b76 100644
--- a/llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-fshr.mir
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-fshr.mir
@@ -1,8 +1,8 @@
 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
 # RUN: llc -mtriple=amdgcn -mcpu=tahiti -run-pass=instruction-select -verify-machineinstrs -o - %s | FileCheck -check-prefix=GCN %s
 # RUN: llc -mtriple=amdgcn -mcpu=fiji -run-pass=instruction-select -verify-machineinstrs -o - %s | FileCheck -check-prefix=GCN %s
-# RUN: llc -mtriple=amdgcn -mcpu=gfx900 -run-pass=instruction-select -verify-machineinstrs -o - %s | FileCheck -check-prefix=GCN %s
-# RUN: llc -mtriple=amdgcn -mcpu=gfx1010 -run-pass=instruction-select -verify-machineinstrs -o - %s | FileCheck -check-prefix=GCN %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx900 -run-pass=instruction-select -verify-machineinstrs -o - %s | FileCheck -check-prefix=GFX9 %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx1010 -run-pass=instruction-select -verify-machineinstrs -o - %s | FileCheck -check-prefix=GFX10 %s
 # RUN: llc -mtriple=amdgcn -mcpu=gfx1100 -mattr=-real-true16 -run-pass=instruction-select -verify-machineinstrs -o - %s | FileCheck -check-prefixes=GFX11 %s
 
 ---
@@ -24,6 +24,24 @@ body: |
     ; GCN-NEXT: [[V_ALIGNBIT_B32_e64_:%[0-9]+]]:vgpr_32 = V_ALIGNBIT_B32_e64 [[COPY]], [[COPY1]], [[COPY2]], implicit $exec
     ; GCN-NEXT: S_ENDPGM 0, implicit [[V_ALIGNBIT_B32_e64_]]
     ;
+    ; GFX9-LABEL: name: fshr_s32
+    ; GFX9: liveins: $vgpr0, $vgpr1, $vgpr2
+    ; GFX9-NEXT: {{  $}}
+    ; GFX9-NEXT: [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr0
+    ; GFX9-NEXT: [[COPY1:%[0-9]+]]:vgpr_32 = COPY $vgpr1
+    ; GFX9-NEXT: [[COPY2:%[0-9]+]]:vgpr_32 = COPY $vgpr2
+    ; GFX9-NEXT: [[V_ALIGNBIT_B32_opsel_e64_:%[0-9]+]]:vgpr_32 = V_ALIGNBIT_B32_opsel_e64 0, [[COPY]], 0, [[COPY1]], 0, [[COPY2]], 0, 0, implicit $exec
+    ; GFX9-NEXT: S_ENDPGM 0, implicit [[V_ALIGNBIT_B32_opsel_e64_]]
+    ;
+    ; GFX10-LABEL: name: fshr_s32
+    ; GFX10: liveins: $vgpr0, $vgpr1, $vgpr2
+    ; GFX10-NEXT: {{  $}}
+    ; GFX10-NEXT: [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr0
+    ; GFX10-NEXT: [[COPY1:%[0-9]+]]:vgpr_32 = COPY $vgpr1
+    ; GFX10-NEXT: [[COPY2:%[0-9]+]]:vgpr_32 = COPY $vgpr2
+    ; GFX10-NEXT: [[V_ALIGNBIT_B32_opsel_e64_:%[0-9]+]]:vgpr_32 = V_ALIGNBIT_B32_opsel_e64 0, [[COPY]], 0, [[COPY1]], 0, [[COPY2]], 0, 0, implicit $exec
+    ; GFX10-NEXT: S_ENDPGM 0, implicit [[V_ALIGNBIT_B32_opsel_e64_]]
+    ;
     ; GFX11-LABEL: name: fshr_s32
     ; GFX11: liveins: $vgpr0, $vgpr1, $vgpr2
     ; GFX11-NEXT: {{  $}}
diff --git a/llvm/test/CodeGen/AMDGPU/branch-folding-implicit-def-subreg.ll b/llvm/test/CodeGen/AMDGPU/branch-folding-implicit-def-subreg.ll
index ae90cfb631e8d..92c63fead15ac 100644
--- a/llvm/test/CodeGen/AMDGPU/branch-folding-implicit-def-subreg.ll
+++ b/llvm/test/CodeGen/AMDGPU/branch-folding-implicit-def-subreg.ll
@@ -766,10 +766,10 @@ define amdgpu_kernel void @f1(ptr addrspace(1) %arg, ptr addrspace(1) %arg1, i64
   ; GFX90A-NEXT:   renamable $vgpr10 = COPY renamable $sgpr22, implicit $exec
   ; GFX90A-NEXT:   renamable $vgpr12_vgpr13 = DS_READ_B64_gfx9 killed renamable $vgpr10, 0, 0, implicit $exec :: (load (s64) from %ir.8, addrspace 3)
   ; GFX90A-NEXT:   renamable $vgpr10 = COPY renamable $sgpr46, implicit $exec
-  ; GFX90A-NEXT:   renamable $vgpr11 = V_ALIGNBIT_B32_e64 killed $sgpr47, killed $vgpr10, 1, implicit $exec
-  ; GFX90A-NEXT:   renamable $vgpr52 = V_ALIGNBIT_B32_e64 $vgpr17, $vgpr16, 1, implicit $exec
+  ; GFX90A-NEXT:   renamable $vgpr11 = V_ALIGNBIT_B32_opsel_e64 0, killed $sgpr47, 0, killed $vgpr10, 0, 1, 0, 0, implicit $exec
+  ; GFX90A-NEXT:   renamable $vgpr52 = V_ALIGNBIT_B32_opsel_e64 0, $vgpr17, 0, $vgpr16, 0, 1, 0, 0, implicit $exec
   ; GFX90A-NEXT:   renamable $vgpr17 = V_CNDMASK_B32_e64 0, 0, 0, 1, $sgpr12_sgpr13, implicit $exec
-  ; GFX90A-NEXT:   renamable $vgpr15 = V_ALIGNBIT_B32_e64 $vgpr15, $vgpr14, 1, implicit $exec
+  ; GFX90A-NEXT:   renamable $vgpr15 = V_ALIGNBIT_B32_opsel_e64 0, $vgpr15, 0, $vgpr14, 0, 1, 0, 0, implicit $exec
   ; GFX90A-NEXT:   renamable $sgpr52_sgpr53 = S_XOR_B64 $exec, -1, implicit-def dead $scc
   ; GFX90A-NEXT:   renamable $sgpr62_sgpr63 = S_OR_B64 renamable $sgpr36_sgpr37, $exec, implicit-def dead $scc
   ; GFX90A-NEXT:   renamable $vgpr10 = COPY renamable $vgpr14, implicit $exec
diff --git a/llvm/test/MC/Disassembler/AMDGPU/gfx10_vop3.txt b/llvm/test/MC/Disassembler/AMDGPU/gfx10_vop3.txt
index 721babdd64245..08ed50d92ba83 100644
--- a/llvm/test/MC/Disassembler/AMDGPU/gfx10_vop3.txt
+++ b/llvm/test/MC/Disassembler/AMDGPU/gfx10_vop3.txt
@@ -1146,6 +1146,18 @@
 # GFX10: v_alignbit_b32 v5, vcc_lo, v2, v3       ; encoding: [0x05,0x00,0x4e,0xd5,0x6a,0x04,0x0e,0x04]
 0x05,0x00,0x4e,0xd5,0x6a,0x04,0x0e,0x04
 
+# GFX10: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,0,0,0] ; encoding: [0x05,0x08,0x4e,0xd5,0x01,0x05,0x0e,0x04]
+0x05,0x08,0x4e,0xd5,0x01,0x05,0x0e,0x04
+
+# GFX10: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,0,0] ; encoding: [0x05,0x18,0x4e,0xd5,0x01,0x05,0x0e,0x04]
+0x05,0x18,0x4e,0xd5,0x01,0x05,0x0e,0x04
+
+# GFX10: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,0] ; encoding: [0x05,0x38,0x4e,0xd5,0x01,0x05,0x0e,0x04]
+0x05,0x38,0x4e,0xd5,0x01,0x05,0x0e,0x04
+
+# GFX10: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,1] ; encoding: [0x05,0x78,0x4e,0xd5,0x01,0x05,0x0e,0x04]
+0x05,0x78,0x4e,0xd5,0x01,0x05,0x0e,0x04
+
 # GFX10: v_alignbyte_b32 v255, v1, v2, v3        ; encoding: [0xff,0x00,0x4f,0xd5,0x01,0x05,0x0e,0x04]
 0xff,0x00,0x4f,0xd5,0x01,0x05,0x0e,0x04
 
@@ -1233,6 +1245,18 @@
 # GFX10: v_alignbyte_b32 v5, vcc_lo, v2, v3      ; encoding: [0x05,0x00,0x4f,0xd5,0x6a,0x04,0x0e,0x04]
 0x05,0x00,0x4f,0xd5,0x6a,0x04,0x0e,0x04
 
+# GFX10: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,0,0,0] ; encoding: [0x05,0x08,0x4f,0xd5,0x01,0x05,0x0e,0x04]
+0x05,0x08,0x4f,0xd5,0x01,0x05,0x0e,0x04
+
+# GFX10: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,0,0] ; encoding: [0x05,0x18,0x4f,0xd5,0x01,0x05,0x0e,0x04]
+0x05,0x18,0x4f,0xd5,0x01,0x05,0x0e,0x04
+
+# GFX10: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,0] ; encoding: [0x05,0x38,0x4f,0xd5,0x01,0x05,0x0e,0x04]
+0x05,0x38,0x4f,0xd5,0x01,0x05,0x0e,0x04
+
+# GFX10: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1] ; encoding: [0x05,0x78,0x4f,0xd5,0x01,0x05,0x0e,0x04]
+0x05,0x78,0x4f,0xd5,0x01,0x05,0x0e,0x04
+
 # GFX10: v_and_b32_e64 v255, v1, v2              ; encoding: [0xff,0x00,0x1b,0xd5,0x01,0x05,0x02,0x00]
 0xff,0x00,0x1b,0xd5,0x01,0x05,0x02,0x00
 
diff --git a/llvm/test/MC/Disassembler/AMDGPU/gfx9_vop3.txt b/llvm/test/MC/Disassembler/AMDGPU/gfx9_vop3.txt
index 618e081525414..802d6368507e2 100644
--- a/llvm/test/MC/Disassembler/AMDGPU/gfx9_vop3.txt
+++ b/llvm/test/MC/Disassembler/AMDGPU/gfx9_vop3.txt
@@ -11310,6 +11310,18 @@
 # CHECK: v_alignbit_b32 v5, v1, v2, exec_hi      ; encoding: [0x05,0x00,0xce,0xd1,0x01,0x05,0xfe,0x01]
 0x05,0x00,0xce,0xd1,0x01,0x05,0xfe,0x01
 
+# CHECK: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,0,0,0] ; encoding: [0x05,0x08,0xce,0xd1,0x01,0x05,0x0e,0x04]
+0x05,0x08,0xce,0xd1,0x01,0x05,0x0e,0x04
+
+# CHECK: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,0,0] ; encoding: [0x05,0x18,0xce,0xd1,0x01,0x05,0x0e,0x04]
+0x05,0x18,0xce,0xd1,0x01,0x05,0x0e,0x04
+
+# CHECK: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,0] ; encoding: [0x05,0x38,0xce,0xd1,0x01,0x05,0x0e,0x04]
+0x05,0x38,0xce,0xd1,0x01,0x05,0x0e,0x04
+
+# CHECK: v_alignbit_b32 v5, v1, v2, v3 op_sel:[1,1,1,1] ; encoding: [0x05,0x78,0xce,0xd1,0x01,0x05,0x0e,0x04]
+0x05,0x78,0xce,0xd1,0x01,0x05,0x0e,0x04
+
 # CHECK: v_alignbyte_b32 v5, v1, v2, v3          ; encoding: [0x05,0x00,0xcf,0xd1,0x01,0x05,0x0e,0x04]
 0x05,0x00,0xcf,0xd1,0x01,0x05,0x0e,0x04
 
@@ -11406,6 +11418,18 @@
 # CHECK: v_alignbyte_b32 v5, v1, v2, exec_hi     ; encoding: [0x05,0x00,0xcf,0xd1,0x01,0x05,0xfe,0x01]
 0x05,0x00,0xcf,0xd1,0x01,0x05,0xfe,0x01
 
+# CHECK: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,0,0,0] ; encoding: [0x05,0x08,0xcf,0xd1,0x01,0x05,0x0e,0x04]
+0x05,0x08,0xcf,0xd1,0x01,0x05,0x0e,0x04
+
+# CHECK: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,0,0] ; encoding: [0x05,0x18,0xcf,0xd1,0x01,0x05,0x0e,0x04]
+0x05,0x18,0xcf,0xd1,0x01,0x05,0x0e,0x04
+
+# CHECK: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,0] ; encoding: [0x05,0x38,0xcf,0xd1,0x01,0x05,0x0e,0x04]
+0x05,0x38,0xcf,0xd1,0x01,0x05,0x0e,0x04
+
+# CHECK: v_alignbyte_b32 v5, v1, v2, v3 op_sel:[1,1,1,1] ; encoding: [0x05,0x78,0xcf,0xd1,0x01,0x05,0x0e,0x04]
+0x05,0x78,0xcf,0xd1,0x01,0x05,0x0e,0x04
+
 # CHECK: v_min3_f32 v5, v1, v2, v3               ; encoding: [0x05,0x00,0xd0,0xd1,0x01,0x05,0x0e,0x04]
 0x05,0x00,0xd0,0xd1,0x01,0x05,0x0e,0x04
 

>From 34dd1664a49af53af03d2ce91bab540f047fc678 Mon Sep 17 00:00:00 2001
From: Jun Wang <jwang86 at yahoo.com>
Date: Mon, 7 Jul 2025 10:14:08 -0700
Subject: [PATCH 3/5] Remove commented lines

---
 llvm/lib/Target/AMDGPU/SIInstructions.td | 48 ------------------------
 1 file changed, 48 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/SIInstructions.td b/llvm/lib/Target/AMDGPU/SIInstructions.td
index 760c78f57610b..114382f6c18aa 100644
--- a/llvm/lib/Target/AMDGPU/SIInstructions.td
+++ b/llvm/lib/Target/AMDGPU/SIInstructions.td
@@ -2497,33 +2497,6 @@ def : GCNPat<pat,
                                   $src1, /* clamp */ 0, /* op_sel */ 0)
 >;
 
-//def : GCNPat<(i32 (trunc (srl i64:$src0, (and i32:$src1, (i32 31))))),
-//     (V_ALIGNBIT_B32_opsel_e64 0, /* src0_modifiers */
-//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),
-//                                0, /* src1_modifiers */
-//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub0)),
-//                                0, /* src2_modifiers */
-//                                $src1, /* clamp */ 0, /* op_sel */ 0)
-//>;
-
-//def : GCNPat<(i32 (trunc (srl i64:$src0, (and i32:$src1, (i32 31))))),
-//     (V_ALIGNBIT_B32_opsel_e64 0, /* src0_modifiers */
-//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),
-//                                0, /* src1_modifiers */
-//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub0)),
-//                                0, /* src2_modifiers */
-//                                $src1, /* clamp */ 0, /* op_sel */ 0)
-//>;
-
-//def : GCNPat<(i32 (trunc (srl i64:$src0, (i32 ShiftAmt32Imm:$src1)))),
-//     (V_ALIGNBIT_B32_opsel_e64 0, /* src0_modifiers */
-//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),
-//                                0, /* src1_modifiers */
-//                               (i32 (EXTRACT_SUBREG (i64 $src0), sub0)),
-//                                0, /* src2_modifiers */
-//                                $src1, /* clamp */ 0, /* op_sel */ 0)
-//>;
-
 def : GCNPat<(fshr i32:$src0, i32:$src1, i32:$src2),
         (V_ALIGNBIT_B32_opsel_e64 /* src0_modifiers */ 0, $src0,
                                   /* src1_modifiers */ 0, $src1,
@@ -3607,7 +3580,6 @@ def : GCNPat <
 // Take the upper 16 bits from V[0] and the lower 16 bits from V[1]
 // Special case, can use V_ALIGNBIT (always uses encoded literal)
 let True16Predicate = NotHasTrue16BitInsts in {
-
 defvar BuildVectorToAlignBitPat =
   (vecTy (DivergentBinFrag<build_vector>
     (Ty !if(!eq(Ty, i16),
@@ -3620,26 +3592,6 @@ def : GCNPat<BuildVectorToAlignBitPat, (V_ALIGNBIT_B32_e64 VGPR_32:$b, VGPR_32:$
 
 let SubtargetPredicate = isGFX9GFX10 in
 def : GCNPat<BuildVectorToAlignBitPat, (V_ALIGNBIT_B32_opsel_e64 0, VGPR_32:$b, 0, VGPR_32:$a, 0, (i32 16), 0, 0)>;
-
-//let SubtargetPredicate = isNotGFX9Plus in
-//def : GCNPat <
-//  (vecTy (DivergentBinFrag<build_vector>
-//    (Ty !if(!eq(Ty, i16),
-//      (Ty (trunc (srl VGPR_32:$a, (i32 16)))),
-//      (Ty (bitconvert (i16 (trunc (srl VGPR_32:$a, (i32 16)))))))),
-//    (Ty VGPR_32:$b))),
-//    (V_ALIGNBIT_B32_e64 VGPR_32:$b, VGPR_32:$a, (i32 16))
-//>;
-
-//let SubtargetPredicate = isGFX9GFX10 in
-//def : GCNPat <
-//  (vecTy (DivergentBinFrag<build_vector>
-//    (Ty !if(!eq(Ty, i16),
-//      (Ty (trunc (srl VGPR_32:$a, (i32 16)))),
-//      (Ty (bitconvert (i16 (trunc (srl VGPR_32:$a, (i32 16)))))))),
-//    (Ty VGPR_32:$b))),
-//    (V_ALIGNBIT_B32_opsel_e64 0, VGPR_32:$b, 0, VGPR_32:$a, 0, (i32 16), 0, 0)
-//>;
 } //True16Predicate = NotHasTrue16BitInsts
 
 let True16Predicate = UseFakeTrue16Insts in

>From 94cab66d4d2e8ffa140505f53d1b1f49a27e9f9c Mon Sep 17 00:00:00 2001
From: Jun Wang <jwang86 at yahoo.com>
Date: Mon, 7 Jul 2025 16:54:02 -0700
Subject: [PATCH 4/5] Add run lines to confirm bswap is matched to v_perm_b32

---
 llvm/lib/Target/AMDGPU/VOP3Instructions.td    |  6 +++---
 .../AMDGPU/GlobalISel/inst-select-bswap.mir   | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/VOP3Instructions.td b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
index 2609c9758d8bc..e7ebc109b5dd5 100644
--- a/llvm/lib/Target/AMDGPU/VOP3Instructions.td
+++ b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
@@ -2252,7 +2252,7 @@ multiclass VOP3_Real_BITOP3_gfx9<bits<10> op, string AsmName, bit isSingle = 0>
 
 // Instructions such as v_alignbyte_b32 allows op_sel in gfx9, but not in vi.
 // The following is created to support that.
-multiclass VOP3OpSel_Real_gfx9_with_names<bits<10> op, string opName, string AsmName> {
+multiclass VOP3OpSel_Real_gfx9_with_name<bits<10> op, string opName, string AsmName> {
   defvar psName = opName#"_e64";
   def _gfx9 : VOP3_Real<!cast<VOP3_Pseudo>(psName), SIEncodingFamily.VI>, // note: encoding family is VI
             VOP3OpSel_gfx9 <op, !cast<VOP3_Pseudo>(psName).Pfl> {
@@ -2328,8 +2328,8 @@ defm V_INTERP_P2_LEGACY_F16 : VOP3Interp_F16_Real_gfx9 <0x276, "V_INTERP_P2_F16"
 defm V_MAD_LEGACY_U16       : VOP3_F16_Real_gfx9 <0x1eb, "V_MAD_U16",       "v_mad_legacy_u16">;
 defm V_MAD_LEGACY_I16       : VOP3_F16_Real_gfx9 <0x1ec, "V_MAD_I16",       "v_mad_legacy_i16">;
 
-defm V_ALIGNBIT_B32_opsel   : VOP3OpSel_Real_gfx9_with_names <0x1ce, "V_ALIGNBIT_B32_opsel", "v_alignbit_b32">;
-defm V_ALIGNBYTE_B32_opsel  : VOP3OpSel_Real_gfx9_with_names <0x1cf, "V_ALIGNBYTE_B32_opsel", "v_alignbyte_b32">;
+defm V_ALIGNBIT_B32_opsel   : VOP3OpSel_Real_gfx9_with_name <0x1ce, "V_ALIGNBIT_B32_opsel", "v_alignbit_b32">;
+defm V_ALIGNBYTE_B32_opsel  : VOP3OpSel_Real_gfx9_with_name <0x1cf, "V_ALIGNBYTE_B32_opsel", "v_alignbyte_b32">;
 
 defm V_MAD_F16_gfx9         : VOP3OpSel_F16_Real_gfx9 <0x203, "v_mad_f16">;
 defm V_MAD_U16_gfx9         : VOP3OpSel_F16_Real_gfx9 <0x204, "v_mad_u16">;
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-bswap.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-bswap.mir
index 5b8c2840b0156..dde566d9643d8 100644
--- a/llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-bswap.mir
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/inst-select-bswap.mir
@@ -1,6 +1,8 @@
 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
 # RUN: llc -mtriple=amdgcn -mcpu=hawaii -run-pass=instruction-select -verify-machineinstrs -o - %s  | FileCheck -check-prefix=GFX7 %s
 # RUN: llc -mtriple=amdgcn -mcpu=fiji -run-pass=instruction-select -verify-machineinstrs -o - %s  | FileCheck -check-prefix=GFX8 %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx900 -run-pass=instruction-select -verify-machineinstrs -o - %s  | FileCheck -check-prefix=GFX9 %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx1010 -run-pass=instruction-select -verify-machineinstrs -o - %s  | FileCheck -check-prefix=GFX10 %s
 
 ---
 name: bswap_i32_vv
@@ -19,6 +21,7 @@ body: |
     ; GFX7-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 16711935
     ; GFX7-NEXT: [[V_BFI_B32_e64_:%[0-9]+]]:vgpr_32 = V_BFI_B32_e64 [[S_MOV_B32_]], [[V_ALIGNBIT_B32_e64_1]], [[V_ALIGNBIT_B32_e64_]], implicit $exec
     ; GFX7-NEXT: S_ENDPGM 0, implicit [[V_BFI_B32_e64_]]
+    ;
     ; GFX8-LABEL: name: bswap_i32_vv
     ; GFX8: liveins: $vgpr0
     ; GFX8-NEXT: {{  $}}
@@ -26,6 +29,22 @@ body: |
     ; GFX8-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 66051
     ; GFX8-NEXT: [[V_PERM_B32_e64_:%[0-9]+]]:vgpr_32 = V_PERM_B32_e64 0, [[COPY]], [[S_MOV_B32_]], implicit $exec
     ; GFX8-NEXT: S_ENDPGM 0, implicit [[V_PERM_B32_e64_]]
+    ;
+    ; GFX9-LABEL: name: bswap_i32_vv
+    ; GFX9: liveins: $vgpr0
+    ; GFX9-NEXT: {{  $}}
+    ; GFX9-NEXT: [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr0
+    ; GFX9-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 66051
+    ; GFX9-NEXT: [[V_PERM_B32_e64_:%[0-9]+]]:vgpr_32 = V_PERM_B32_e64 0, [[COPY]], [[S_MOV_B32_]], implicit $exec
+    ; GFX9-NEXT: S_ENDPGM 0, implicit [[V_PERM_B32_e64_]]
+    ;
+    ; GFX10-LABEL: name: bswap_i32_vv
+    ; GFX10: liveins: $vgpr0
+    ; GFX10-NEXT: {{  $}}
+    ; GFX10-NEXT: [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr0
+    ; GFX10-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 66051
+    ; GFX10-NEXT: [[V_PERM_B32_e64_:%[0-9]+]]:vgpr_32 = V_PERM_B32_e64 0, [[COPY]], [[S_MOV_B32_]], implicit $exec
+    ; GFX10-NEXT: S_ENDPGM 0, implicit [[V_PERM_B32_e64_]]
     %0:vgpr(s32) = COPY $vgpr0
     %1:vgpr(s32) = G_BSWAP %0
     S_ENDPGM 0, implicit %1

>From 609ac2fc5a075a323435e95eb7aa0500ed107933 Mon Sep 17 00:00:00 2001
From: Jun Wang <jwang86 at yahoo.com>
Date: Tue, 8 Jul 2025 15:00:46 -0700
Subject: [PATCH 5/5] Add comment

---
 llvm/lib/Target/AMDGPU/SIInstructions.td | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/llvm/lib/Target/AMDGPU/SIInstructions.td b/llvm/lib/Target/AMDGPU/SIInstructions.td
index 114382f6c18aa..4419ce00b473c 100644
--- a/llvm/lib/Target/AMDGPU/SIInstructions.td
+++ b/llvm/lib/Target/AMDGPU/SIInstructions.td
@@ -3104,6 +3104,8 @@ def : GCNPat <
                     (i32 (EXTRACT_SUBREG $a, sub0))), (i32 1))
 >;
 
+// This pattern for bswap is used for pre-GFX8. For GFX8+, bswap is mapped
+// to V_PERM_B32.
 let True16Predicate = NotHasTrue16BitInsts in
 def : GCNPat <
   (i32 (bswap i32:$a)),



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