[AMDGPU] Fix immediate sign during V_MOV_B64_PSEUDO expansion

[rampitec]

Summary

Creating a V_MOV_B32 with zero extended immediate source
prevented conversion to V_BFREV_B32.

llvm/lib/Target/AMDGPU/SIInstrInfo.cpp

if (SrcOp.isImm()) {
           .addImm(Lo.getSExtValue())
           .addImm(0)  // op_sel_lo
           .addImm(0)  // op_sel_hi
           .addImm(0)  // neg_lo
           .addImm(0)  // neg_hi
           .addImm(0); // clamp
       } else {
         BuildMI(MBB, MI, DL, get(AMDGPU::V_MOV_B32_e32), DstLo)
-          .addImm(Lo.getZExtValue())
+          .addImm(Lo.getSExtValue())
           .addReg(Dst, RegState::Implicit | RegState::Define);
         BuildMI(MBB, MI, DL, get(AMDGPU::V_MOV_B32_e32), DstHi)
-          .addImm(Hi.getZExtValue())
+          .addImm(Hi.getSExtValue())
           .addReg(Dst, RegState::Implicit | RegState::Define);
       }
     } else {
       assert(SrcOp.isReg());
       if (ST.hasPackedFP32Ops() &&
           !RI.isAGPR(MBB.getParent()->getRegInfo(), SrcOp.getReg())) {
         BuildMI(MBB, MI, DL, get(AMDGPU::V_PK_MOV_B32), Dst)
           .addImm(SISrcMods::OP_SEL_1) // src0_mod

llvm/test/CodeGen/AMDGPU/v_mov_b64_expand_and_shrink.mir

+# RUN: llc -march=amdgcn -mcpu=gfx900 -run-pass postrapseudos,si-shrink-instructions -verify-machineinstrs %s -o - | FileCheck -check-prefix=GCN %s
+
+---
+# GCN-LABEL: name: expand_imm64_sext_shrink_to_bfrev
+# GCN: $vgpr0 = V_MOV_B32_e32 0, implicit $exec, implicit-def $vgpr0_vgpr1
+# GCN: $vgpr1 = V_BFREV_B32_e32 1, implicit $exec, implicit-def $vgpr0_vgpr1
+name:            expand_imm64_sext_shrink_to_bfrev
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    $vgpr0_vgpr1 = V_MOV_B64_PSEUDO -9223372036854775808, implicit $exec
+...

llvm/test/CodeGen/AMDGPU/v_mov_b64_expansion.mir

 # GFX90A: $vgpr0_vgpr1 = V_PK_MOV_B32 8, $sgpr2_sgpr3, 12, $sgpr2_sgpr3, 0, 0, 0, 0, 0, implicit $exec
 name: v_mov_b64_from_sgpr
 body: |
   bb.0:
     $vgpr0_vgpr1 = V_MOV_B64_PSEUDO $sgpr2_sgpr3, implicit $exec
 ...
 
 # GCN-LABEL: name: v_mov_b64_from_sext_inline_imm
-# GFX900: $vgpr0 = V_MOV_B32_e32 4294967294, implicit $exec, implicit-def $vgpr0_vgpr1
-# GFX900: $vgpr1 = V_MOV_B32_e32 4294967295, implicit $exec, implicit-def $vgpr0_vgpr1
-# GFX90A: $vgpr0 = V_MOV_B32_e32 4294967294, implicit $exec, implicit-def $vgpr0_vgpr1
-# GFX90A: $vgpr1 = V_MOV_B32_e32 4294967295, implicit $exec, implicit-def $vgpr0_vgpr1
+# GFX900: $vgpr0 = V_MOV_B32_e32 -2, implicit $exec, implicit-def $vgpr0_vgpr1
+# GFX900: $vgpr1 = V_MOV_B32_e32 -1, implicit $exec, implicit-def $vgpr0_vgpr1
+# GFX90A: $vgpr0 = V_MOV_B32_e32 -2, implicit $exec, implicit-def $vgpr0_vgpr1
+# GFX90A: $vgpr1 = V_MOV_B32_e32 -1, implicit $exec, implicit-def $vgpr0_vgpr1
 name: v_mov_b64_from_sext_inline_imm
 body: |
   bb.0:
     $vgpr0_vgpr1 = V_MOV_B64_PSEUDO 18446744073709551614, implicit $exec
 ...
 
 # GCN-LABEL: name: v_mov_b64_from_lit
 # GCN: $vgpr0 = V_MOV_B32_e32 1430494974, implicit $exec, implicit-def $vgpr0_vgpr1
-# GCN: $vgpr1 = V_MOV_B32_e32 4294734465, implicit $exec, implicit-def $vgpr0_vgpr1
+# GCN: $vgpr1 = V_MOV_B32_e32 -232831, implicit $exec, implicit-def $vgpr0_vgpr1
 name: v_mov_b64_from_lit
 body: |
   bb.0:
     $vgpr0_vgpr1 = V_MOV_B64_PSEUDO 18445744073609551614, implicit $exec
 ...
 
 # GCN-LABEL: name: v_mov_b64_from_first_inline_imm
-# GCN: $vgpr0 = V_MOV_B32_e32 4294967295, implicit $exec, implicit-def $vgpr0_vgpr1
+# GCN: $vgpr0 = V_MOV_B32_e32 -1, implicit $exec, implicit-def $vgpr0_vgpr1
 # GCN: $vgpr1 = V_MOV_B32_e32 268435455, implicit $exec, implicit-def $vgpr0_vgpr1
 name: v_mov_b64_from_first_inline_imm
 body: |
   bb.0:
     $vgpr0_vgpr1 = V_MOV_B64_PSEUDO 1152921504606846975, implicit $exec
 ...
 
 # GCN-LABEL: name: v_mov_b64_from_second_inline_imm
 # GCN: $vgpr0 = V_MOV_B32_e32 268435455, implicit $exec, implicit-def $vgpr0_vgpr1
-# GCN: $vgpr1 = V_MOV_B32_e32 4294967295, implicit $exec, implicit-def $vgpr0_vgpr1
+# GCN: $vgpr1 = V_MOV_B32_e32 -1, implicit $exec, implicit-def $vgpr0_vgpr1
 name: v_mov_b64_from_second_inline_imm
 body: |
   bb.0:
     $vgpr0_vgpr1 = V_MOV_B64_PSEUDO 18446744069683019775, implicit $exec
 ...
 
 # GCN-LABEL: name: v_mov_b64_from_same_sext_inline_imm
-# GFX900: $vgpr0 = V_MOV_B32_e32 4294967295, implicit $exec, implicit-def $vgpr0_vgpr1
-# GFX900: $vgpr1 = V_MOV_B32_e32 4294967295, implicit $exec, implicit-def $vgpr0_vgpr1
+# GFX900: $vgpr0 = V_MOV_B32_e32 -1, implicit $exec, implicit-def $vgpr0_vgpr1
+# GFX900: $vgpr1 = V_MOV_B32_e32 -1, implicit $exec, implicit-def $vgpr0_vgpr1
 # GFX90A: $vgpr0_vgpr1 = V_PK_MOV_B32 8, -1, 8, -1, 0, 0, 0, 0, 0, implicit $exec
 name: v_mov_b64_from_same_sext_inline_imm
 body: |
   bb.0:
     $vgpr0_vgpr1 = V_MOV_B64_PSEUDO 18446744073709551615, implicit $exec
 ...
 
 # GCN-LABEL: name: v_mov_b64_from_same_fp_inline_imm
 # GFX900: $vgpr0 = V_MOV_B32_e32 1065353216, implicit $exec, implicit-def $vgpr0_vgpr1
 # GFX900: $vgpr1 = V_MOV_B32_e32 1065353216, implicit $exec, implicit-def $vgpr0_vgpr1
 # GFX90A: $vgpr0_vgpr1 = V_PK_MOV_B32 8, 1065353216, 8, 1065353216, 0, 0, 0, 0, 0, implicit $exec
 name: v_mov_b64_from_same_fp_inline_imm
 body: |
   bb.0:
     $vgpr0_vgpr1 = V_MOV_B64_PSEUDO 4575657222473777152, implicit $exec
 ...