[llvm] r288185 - AMDGPU: Materialize frame index before add

[Matt Arsenault via llvm-commits]

Author: arsenm
Date: Tue Nov 29 13:20:48 2016
New Revision: 288185

URL: http://llvm.org/viewvc/llvm-project?rev=288185&view=rev
Log:
AMDGPU: Materialize frame index before add

It isn't generally safe to fold the frame index
directly into the operand since it will possibly
not be an inline immediate after it is expanded.

This surprisingly seems to produce better code, since
the FI doesn't prevent folding other immediate operands.

Modified:
    llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.cpp
    llvm/trunk/test/CodeGen/AMDGPU/local-stack-slot-bug.ll

Modified: llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.cpp?rev=288185&r1=288184&r2=288185&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.cpp Tue Nov 29 13:20:48 2016
@@ -245,12 +245,17 @@ void SIRegisterInfo::materializeFrameBas
   unsigned UnusedCarry = MRI.createVirtualRegister(&AMDGPU::SReg_64RegClass);
   unsigned OffsetReg = MRI.createVirtualRegister(&AMDGPU::SReg_32_XM0RegClass);
 
+  unsigned FIReg = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
+
   BuildMI(*MBB, Ins, DL, TII->get(AMDGPU::S_MOV_B32), OffsetReg)
     .addImm(Offset);
+  BuildMI(*MBB, Ins, DL, TII->get(AMDGPU::V_MOV_B32_e32), FIReg)
+    .addFrameIndex(FrameIdx);
+
   BuildMI(*MBB, Ins, DL, TII->get(AMDGPU::V_ADD_I32_e64), BaseReg)
     .addReg(UnusedCarry, RegState::Define | RegState::Dead)
     .addReg(OffsetReg, RegState::Kill)
-    .addFrameIndex(FrameIdx);
+    .addReg(FIReg);
 }
 
 void SIRegisterInfo::resolveFrameIndex(MachineInstr &MI, unsigned BaseReg,

Modified: llvm/trunk/test/CodeGen/AMDGPU/local-stack-slot-bug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/local-stack-slot-bug.ll?rev=288185&r1=288184&r2=288185&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AMDGPU/local-stack-slot-bug.ll (original)
+++ llvm/trunk/test/CodeGen/AMDGPU/local-stack-slot-bug.ll Tue Nov 29 13:20:48 2016
@@ -7,15 +7,16 @@
 ;
 ; CHECK-LABEL: {{^}}main:
 
+; CHECK: v_mov_b32_e32 [[BASE_FI:v[0-9]+]], 0{{$}}
+
 ; FIXME: add 0?
-; CHECK-DAG: s_movk_i32 [[K0:s[0-9]+]], 0x140
-; CHECK-DAG: v_add_i32_e64 [[ADD_K0:v[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, [[K0]], 0
+; CHECK-DAG: v_add_i32_e32 [[ADD_K0:v[0-9]+]], vcc, 0x140, [[BASE_FI]]
 
 ; CHECK-DAG: v_lshlrev_b32_e32 [[BYTES:v[0-9]+]], 2, v0
 ; CHECK-DAG: buffer_store_dword {{v[0-9]+}}, [[ADD_K0]], {{s\[[0-9]+:[0-9]+\]}}, {{s[0-9]+}} offen{{$}}
 
 ; CHECK-DAG: v_add_i32_e32 [[HI_OFF:v[0-9]+]], vcc, 0x200, [[BYTES]]
-; CHECK-DAG: v_add_i32_e32 [[LO_OFF:v[0-9]+]], vcc, 0, [[BYTES]]
+; CHECK-DAG: v_add_i32_e32 [[LO_OFF:v[0-9]+]], vcc, [[BASE_FI]], [[BYTES]]
 
 ; CHECK: buffer_load_dword {{v[0-9]+}}, [[LO_OFF]], {{s\[[0-9]+:[0-9]+\]}}, {{s[0-9]+}} offen
 ; CHECK: buffer_load_dword {{v[0-9]+}}, [[HI_OFF]], {{s\[[0-9]+:[0-9]+\]}}, {{s[0-9]+}} offen