AMDGPU: Inline constant when materalizing FI with add on gfx9

This was relying on the SGPR usable for the carry out clobber to also
be used for the input. There was no carry out on gfx9. With no carry
out clobber to worry about, so the literal can just be directly used
with a VOP2 add.

llvm-svn: 371791

4 files changed, 53 insertions, 7 deletions

diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index fe57435204a..3386f80beb8 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -6110,7 +6110,7 @@ MachineInstrBuilder SIInstrInfo::getAddNoCarry(MachineBasicBlock &MBB,
                                                Register DestReg,
                                                RegScavenger &RS) const {
   if (ST.hasAddNoCarry())
-    return BuildMI(MBB, I, DL, get(AMDGPU::V_ADD_U32_e64), DestReg);
+    return BuildMI(MBB, I, DL, get(AMDGPU::V_ADD_U32_e32), DestReg);
 
   Register UnusedCarry = RS.scavengeRegister(RI.getBoolRC(), I, 0, false);
   // TODO: Users need to deal with this.
diff --git a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
index 235de006a1d..7967d9c9fb9 100644
--- a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
@@ -1285,12 +1285,15 @@ void SIRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI,
               .addImm(ST.getWavefrontSizeLog2())
               .addReg(DiffReg, RegState::Kill);
 
+            const bool IsVOP2 = MIB->getOpcode() == AMDGPU::V_ADD_U32_e32;
+
             // TODO: Fold if use instruction is another add of a constant.
-            if (AMDGPU::isInlinableLiteral32(Offset, ST.hasInv2PiInlineImm())) {
+            if (IsVOP2 || AMDGPU::isInlinableLiteral32(Offset, ST.hasInv2PiInlineImm())) {
               // FIXME: This can fail
               MIB.addImm(Offset);
               MIB.addReg(ScaledReg, RegState::Kill);
-              MIB.addImm(0); // clamp bit
+              if (!IsVOP2)
+                MIB.addImm(0); // clamp bit
             } else {
               Register ConstOffsetReg =
                 RS->scavengeRegister(&AMDGPU::SReg_32_XM0RegClass, MIB, 0, false);
diff --git a/llvm/test/CodeGen/AMDGPU/frame-index-elimination.ll b/llvm/test/CodeGen/AMDGPU/frame-index-elimination.ll
index 0d8e7456876..b25a40f443c 100644
--- a/llvm/test/CodeGen/AMDGPU/frame-index-elimination.ll
+++ b/llvm/test/CodeGen/AMDGPU/frame-index-elimination.ll
@@ -176,13 +176,13 @@ ret:
 ; Added offset can't be used with VOP3 add
 ; GCN-LABEL: {{^}}func_other_fi_user_non_inline_imm_offset_i32:
 ; GCN: s_sub_u32 [[SUB:s[0-9]+|vcc_lo|vcc_hi]], s32, s33
-; GCN-DAG: s_movk_i32 [[K:s[0-9]+|vcc_lo|vcc_hi]], 0x200
+; CI-DAG: s_movk_i32 [[K:s[0-9]+|vcc_lo|vcc_hi]], 0x200
 
 ; CI-DAG: v_lshr_b32_e64 [[SCALED:v[0-9]+]], [[SUB]], 6
 ; CI: v_add_i32_e32 [[VZ:v[0-9]+]], vcc, [[K]], [[SCALED]]
 
 ; GFX9-DAG: v_lshrrev_b32_e64 [[SCALED:v[0-9]+]], 6, [[SUB]]
-; GFX9: v_add_u32_e32 [[VZ:v[0-9]+]], [[K]], [[SCALED]]
+; GFX9: v_add_u32_e32 [[VZ:v[0-9]+]], 0x200, [[SCALED]]
 
 ; GCN: v_mul_u32_u24_e32 [[VZ]], 9, [[VZ]]
 ; GCN: ds_write_b32 v0, [[VZ]]
@@ -200,13 +200,13 @@ define void @func_other_fi_user_non_inline_imm_offset_i32() #0 {
 
 ; GCN-LABEL: {{^}}func_other_fi_user_non_inline_imm_offset_i32_vcc_live:
 ; GCN: s_sub_u32 [[DIFF:s[0-9]+]], s32, s33
-; GCN-DAG: s_movk_i32 [[OFFSET:s[0-9]+]], 0x200
+; CI-DAG: s_movk_i32 [[OFFSET:s[0-9]+]], 0x200
 
 ; CI-DAG: v_lshr_b32_e64 [[SCALED:v[0-9]+]], [[DIFF]], 6
 ; CI: v_add_i32_e64 [[VZ:v[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, [[OFFSET]], [[SCALED]]
 
 ; GFX9-DAG: v_lshrrev_b32_e64 [[SCALED:v[0-9]+]], 6, [[DIFF]]
-; GFX9: v_add_u32_e32 [[VZ:v[0-9]+]], [[OFFSET]], [[SCALED]]
+; GFX9: v_add_u32_e32 [[VZ:v[0-9]+]], 0x200, [[SCALED]]
 
 ; GCN: v_mul_u32_u24_e32 [[VZ]], 9, [[VZ]]
 ; GCN: ds_write_b32 v0, [[VZ]]
diff --git a/llvm/test/CodeGen/AMDGPU/pei-scavenge-sgpr-gfx9.mir b/llvm/test/CodeGen/AMDGPU/pei-scavenge-sgpr-gfx9.mir
new file mode 100644
index 00000000000..90afb185ccb
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/pei-scavenge-sgpr-gfx9.mir
@@ -0,0 +1,43 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -verify-machineinstrs -run-pass=prologepilog %s -o - | FileCheck %s
+
+# Test what happens when an SGPR is unavailable for the unused add. The non-inline constant needs to be folded into the add instruction and not materialized in a register.
+
+---
+name: scavenge_sgpr_pei_no_sgprs
+tracksRegLiveness: true
+
+stack:
+  - { id: 0, type: default, offset: 0, size: 4, alignment: 8192 }
+  - { id: 1, type: default, offset: 0, size: 4, alignment: 8192 }
+
+machineFunctionInfo:
+  isEntryFunction: false
+  scratchRSrcReg:  $sgpr0_sgpr1_sgpr2_sgpr3
+  scratchWaveOffsetReg: $sgpr34
+  frameOffsetReg:  $sgpr33
+  stackPtrOffsetReg:  $sgpr32
+
+body:             |
+  bb.0:
+    liveins: $vgpr1
+
+    ; CHECK-LABEL: name: scavenge_sgpr_pei_no_sgprs
+    ; CHECK: liveins: $vgpr1
+    ; CHECK: $sgpr27 = frame-setup COPY $sgpr33
+    ; CHECK: $sgpr4 = frame-setup S_ADD_U32 $sgpr32, 524224, implicit-def $scc
+    ; CHECK: $sgpr33 = frame-setup S_AND_B32 killed $sgpr4, 4294443008, implicit-def $scc
+    ; CHECK: $sgpr32 = frame-setup S_ADD_U32 $sgpr32, 1572864, implicit-def $scc
+    ; CHECK: S_NOP 0, implicit-def $sgpr4, implicit-def $sgpr5, implicit-def $sgpr6, implicit-def $sgpr7, implicit-def $sgpr8, implicit-def $sgpr9, implicit-def $sgpr10, implicit-def $sgpr11, implicit-def $sgpr12, implicit-def $sgpr13, implicit-def $sgpr14, implicit-def $sgpr15, implicit-def $sgpr16, implicit-def $sgpr17, implicit-def $sgpr18, implicit-def $sgpr19, implicit-def $sgpr20, implicit-def $sgpr21, implicit-def $sgpr22, implicit-def $sgpr23, implicit-def $sgpr24, implicit-def $sgpr25, implicit-def $sgpr26, implicit-def $sgpr17, implicit-def $sgpr28, implicit-def $sgpr29, implicit-def $sgpr30, implicit-def $sgpr31, implicit-def $vcc
+    ; CHECK: $sgpr33 = S_SUB_U32 $sgpr33, $sgpr34, implicit-def $scc
+    ; CHECK: $vgpr3 = V_LSHRREV_B32_e64 6, killed $sgpr33, implicit $exec
+    ; CHECK: $vgpr2 = V_ADD_U32_e32 8192, killed $vgpr3, implicit $exec
+    ; CHECK: $sgpr33 = S_ADD_U32 $sgpr33, $sgpr34, implicit-def $scc
+    ; CHECK: $vgpr0 = V_OR_B32_e32 killed $vgpr2, $vgpr1, implicit $exec, implicit $sgpr4, implicit $sgpr5, implicit $sgpr6, implicit $sgpr7, implicit $sgpr8, implicit $sgpr9, implicit $sgpr10, implicit $sgpr11, implicit $sgpr12, implicit $sgpr13, implicit $sgpr14, implicit $sgpr15, implicit $sgpr16, implicit $sgpr17, implicit $sgpr18, implicit $sgpr19, implicit $sgpr20, implicit $sgpr21, implicit $sgpr22, implicit $sgpr23, implicit $sgpr24, implicit $sgpr25, implicit $sgpr26, implicit $sgpr17, implicit $sgpr28, implicit $sgpr29, implicit $sgpr30, implicit $sgpr31
+    ; CHECK: $sgpr32 = frame-destroy S_SUB_U32 $sgpr32, 1572864, implicit-def $scc
+    ; CHECK: $sgpr33 = frame-setup COPY $sgpr27
+    ; CHECK: S_ENDPGM 0, implicit $vcc
+    S_NOP 0, implicit-def $sgpr4, implicit-def $sgpr5, implicit-def $sgpr6, implicit-def $sgpr7, implicit-def $sgpr8, implicit-def $sgpr9, implicit-def $sgpr10, implicit-def $sgpr11, implicit-def $sgpr12, implicit-def $sgpr13, implicit-def $sgpr14, implicit-def $sgpr15, implicit-def $sgpr16, implicit-def $sgpr17, implicit-def $sgpr18, implicit-def $sgpr19, implicit-def $sgpr20, implicit-def $sgpr21, implicit-def $sgpr22, implicit-def $sgpr23, implicit-def $sgpr24, implicit-def $sgpr25, implicit-def $sgpr26, implicit-def $sgpr17, implicit-def $sgpr28, implicit-def $sgpr29, implicit-def $sgpr30, implicit-def $sgpr31, implicit-def $vcc
+    $vgpr0 = V_OR_B32_e32 %stack.1, $vgpr1, implicit $exec, implicit $sgpr4, implicit $sgpr5, implicit $sgpr6, implicit $sgpr7, implicit $sgpr8, implicit $sgpr9, implicit $sgpr10, implicit $sgpr11, implicit $sgpr12, implicit $sgpr13, implicit $sgpr14, implicit $sgpr15, implicit $sgpr16, implicit $sgpr17, implicit $sgpr18, implicit $sgpr19, implicit $sgpr20, implicit $sgpr21, implicit $sgpr22, implicit $sgpr23, implicit $sgpr24, implicit $sgpr25, implicit $sgpr26, implicit $sgpr17, implicit $sgpr28, implicit $sgpr29, implicit $sgpr30, implicit $sgpr31
+    S_ENDPGM 0, implicit $vcc
+...