forked from OSchip/llvm-project
[AMDGPU] Fix VGPR spills where offset doesn't fit in 12 bits
Scale the offset of VGPR spills by the wave size when it cannot fit in the 12-bit offset immediate field and so is added to the soffset SGPR. This accounts for hardware swizzling of scratch memory. Differential Revision: https://reviews.llvm.org/D49448 llvm-svn: 338060
This commit is contained in:
Scott Linder
parent
6d6eab66e0
commit
eb1f75d561
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@ -532,22 +532,29 @@ void SIRegisterInfo::buildSpillLoadStore(MachineBasicBlock::iterator MI,
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const DebugLoc &DL = MI->getDebugLoc();
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bool IsStore = Desc.mayStore();
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bool RanOutOfSGPRs = false;
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bool Scavenged = false;
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unsigned SOffset = ScratchOffsetReg;
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const unsigned EltSize = 4;
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const TargetRegisterClass *RC = getRegClassForReg(MF->getRegInfo(), ValueReg);
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unsigned NumSubRegs = AMDGPU::getRegBitWidth(RC->getID()) / 32;
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unsigned Size = NumSubRegs * 4;
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unsigned NumSubRegs = AMDGPU::getRegBitWidth(RC->getID()) / (EltSize * CHAR_BIT);
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unsigned Size = NumSubRegs * EltSize;
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int64_t Offset = InstOffset + MFI.getObjectOffset(Index);
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const int64_t OriginalImmOffset = Offset;
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int64_t ScratchOffsetRegDelta = 0;
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unsigned Align = MFI.getObjectAlignment(Index);
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const MachinePointerInfo &BasePtrInfo = MMO->getPointerInfo();
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if (!isUInt<12>(Offset + Size)) {
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assert((Offset % EltSize) == 0 && "unexpected VGPR spill offset");
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if (!isUInt<12>(Offset + Size - EltSize)) {
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SOffset = AMDGPU::NoRegister;
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// We currently only support spilling VGPRs to EltSize boundaries, meaning
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// we can simplify the adjustment of Offset here to just scale with
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// WavefrontSize.
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Offset *= ST.getWavefrontSize();
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// We don't have access to the register scavenger if this function is called
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// during PEI::scavengeFrameVirtualRegs().
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if (RS)
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@ -561,8 +568,8 @@ void SIRegisterInfo::buildSpillLoadStore(MachineBasicBlock::iterator MI,
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// add the offset directly to the ScratchOffset register, and then
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// subtract the offset after the spill to return ScratchOffset to it's
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// original value.
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RanOutOfSGPRs = true;
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SOffset = ScratchOffsetReg;
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ScratchOffsetRegDelta = Offset;
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} else {
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Scavenged = true;
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}
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@ -574,8 +581,6 @@ void SIRegisterInfo::buildSpillLoadStore(MachineBasicBlock::iterator MI,
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Offset = 0;
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}
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const unsigned EltSize = 4;
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for (unsigned i = 0, e = NumSubRegs; i != e; ++i, Offset += EltSize) {
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unsigned SubReg = NumSubRegs == 1 ?
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ValueReg : getSubReg(ValueReg, getSubRegFromChannel(i));
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@ -607,11 +612,11 @@ void SIRegisterInfo::buildSpillLoadStore(MachineBasicBlock::iterator MI,
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MIB.addReg(ValueReg, RegState::Implicit | SrcDstRegState);
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}
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if (RanOutOfSGPRs) {
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if (ScratchOffsetRegDelta != 0) {
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// Subtract the offset we added to the ScratchOffset register.
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BuildMI(*MBB, MI, DL, TII->get(AMDGPU::S_SUB_U32), ScratchOffsetReg)
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.addReg(ScratchOffsetReg)
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.addImm(OriginalImmOffset);
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.addReg(ScratchOffsetReg)
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.addImm(ScratchOffsetRegDelta);
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}
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}
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@ -0,0 +1,213 @@
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; RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -enable-misched=0 -post-RA-scheduler=0 -stress-regalloc=8 < %s | FileCheck %s
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; Test that the VGPR spiller correctly switches to SGPR offsets when the
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; instruction offset field would overflow, and that it accounts for memory
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; swizzling.
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; CHECK-LABEL: test_inst_offset_kernel
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define amdgpu_kernel void @test_inst_offset_kernel() {
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entry:
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; Occupy 4092 bytes of scratch, so the offset of the spill of %a just fits in
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; the instruction offset field.
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%alloca = alloca i8, i32 4088, align 4, addrspace(5)
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%buf = bitcast i8 addrspace(5)* %alloca to i32 addrspace(5)*
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%aptr = getelementptr i32, i32 addrspace(5)* %buf, i32 1
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s{{[0-9]+}} offset:4092 ; 4-byte Folded Spill
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%a = load volatile i32, i32 addrspace(5)* %aptr
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; Force %a to spill.
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call void asm sideeffect "", "~{v0},~{v1},~{v2},~{v3},~{v4},~{v5},~{v6},~{v7}" ()
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%outptr = getelementptr i32, i32 addrspace(5)* %buf, i32 1
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store volatile i32 %a, i32 addrspace(5)* %outptr
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ret void
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}
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; CHECK-LABEL: test_sgpr_offset_kernel
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define amdgpu_kernel void @test_sgpr_offset_kernel() {
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entry:
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; Occupy 4096 bytes of scratch, so the offset of the spill of %a does not
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; fit in the instruction, and has to live in the SGPR offset.
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%alloca = alloca i8, i32 4092, align 4, addrspace(5)
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%buf = bitcast i8 addrspace(5)* %alloca to i32 addrspace(5)*
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%aptr = getelementptr i32, i32 addrspace(5)* %buf, i32 1
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; 0x40000 / 64 = 4096 (for wave64)
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; CHECK: s_add_u32 s7, s7, 0x40000
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s7 ; 4-byte Folded Spill
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; CHECK: s_sub_u32 s7, s7, 0x40000
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%a = load volatile i32, i32 addrspace(5)* %aptr
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; Force %a to spill
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call void asm sideeffect "", "~{v0},~{v1},~{v2},~{v3},~{v4},~{v5},~{v6},~{v7}" ()
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%outptr = getelementptr i32, i32 addrspace(5)* %buf, i32 1
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store volatile i32 %a, i32 addrspace(5)* %outptr
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ret void
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}
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; CHECK-LABEL: test_sgpr_offset_subregs_kernel
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define amdgpu_kernel void @test_sgpr_offset_subregs_kernel() {
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entry:
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; Occupy 4088 bytes of scratch, so that the spill of the last subreg of %a
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; still fits below offset 4096 (4088 + 8 - 4 = 4092), and can be placed in
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; the instruction offset field.
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%alloca = alloca i8, i32 4084, align 4, addrspace(5)
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%bufv1 = bitcast i8 addrspace(5)* %alloca to i32 addrspace(5)*
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%bufv2 = bitcast i8 addrspace(5)* %alloca to <2 x i32> addrspace(5)*
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s{{[0-9]+}} offset:4088 ; 4-byte Folded Spill
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s{{[0-9]+}} offset:4092 ; 4-byte Folded Spill
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%aptr = getelementptr <2 x i32>, <2 x i32> addrspace(5)* %bufv2, i32 1
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%a = load volatile <2 x i32>, <2 x i32> addrspace(5)* %aptr
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; Force %a to spill.
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call void asm sideeffect "", "~{v0},~{v1},~{v2},~{v3},~{v4},~{v5},~{v6},~{v7}" ()
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; Ensure the alloca sticks around.
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%bptr = getelementptr i32, i32 addrspace(5)* %bufv1, i32 1
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%b = load volatile i32, i32 addrspace(5)* %bptr
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; Ensure the spill is of the full super-reg.
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call void asm sideeffect "; $0", "r"(<2 x i32> %a)
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ret void
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}
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; CHECK-LABEL: test_inst_offset_subregs_kernel
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define amdgpu_kernel void @test_inst_offset_subregs_kernel() {
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entry:
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; Occupy 4092 bytes of scratch, so that the spill of the last subreg of %a
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; does not fit below offset 4096 (4092 + 8 - 4 = 4096), and has to live
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; in the SGPR offset.
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%alloca = alloca i8, i32 4088, align 4, addrspace(5)
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%bufv1 = bitcast i8 addrspace(5)* %alloca to i32 addrspace(5)*
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%bufv2 = bitcast i8 addrspace(5)* %alloca to <2 x i32> addrspace(5)*
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; 0x3ff00 / 64 = 4092 (for wave64)
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; CHECK: s_add_u32 s7, s7, 0x3ff00
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s7 ; 4-byte Folded Spill
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s7 offset:4 ; 4-byte Folded Spill
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; CHECK: s_sub_u32 s7, s7, 0x3ff00
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%aptr = getelementptr <2 x i32>, <2 x i32> addrspace(5)* %bufv2, i32 1
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%a = load volatile <2 x i32>, <2 x i32> addrspace(5)* %aptr
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; Force %a to spill.
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call void asm sideeffect "", "~{v0},~{v1},~{v2},~{v3},~{v4},~{v5},~{v6},~{v7}" ()
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; Ensure the alloca sticks around.
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%bptr = getelementptr i32, i32 addrspace(5)* %bufv1, i32 1
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%b = load volatile i32, i32 addrspace(5)* %bptr
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; Ensure the spill is of the full super-reg.
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call void asm sideeffect "; $0", "r"(<2 x i32> %a)
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ret void
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}
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; CHECK-LABEL: test_inst_offset_function
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define void @test_inst_offset_function() {
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entry:
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; Occupy 4092 bytes of scratch, so the offset of the spill of %a just fits in
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; the instruction offset field.
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%alloca = alloca i8, i32 4088, align 4, addrspace(5)
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%buf = bitcast i8 addrspace(5)* %alloca to i32 addrspace(5)*
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%aptr = getelementptr i32, i32 addrspace(5)* %buf, i32 1
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s{{[0-9]+}} offset:4092 ; 4-byte Folded Spill
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%a = load volatile i32, i32 addrspace(5)* %aptr
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; Force %a to spill.
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call void asm sideeffect "", "~{v0},~{v1},~{v2},~{v3},~{v4},~{v5},~{v6},~{v7}" ()
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%outptr = getelementptr i32, i32 addrspace(5)* %buf, i32 1
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store volatile i32 %a, i32 addrspace(5)* %outptr
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ret void
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}
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; CHECK-LABEL: test_sgpr_offset_function
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define void @test_sgpr_offset_function() {
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entry:
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; Occupy 4096 bytes of scratch, so the offset of the spill of %a does not
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; fit in the instruction, and has to live in the SGPR offset.
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%alloca = alloca i8, i32 4092, align 4, addrspace(5)
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%buf = bitcast i8 addrspace(5)* %alloca to i32 addrspace(5)*
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%aptr = getelementptr i32, i32 addrspace(5)* %buf, i32 1
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; 0x40000 / 64 = 4096 (for wave64)
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; CHECK: s_add_u32 s5, s5, 0x40000
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s5 ; 4-byte Folded Spill
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; CHECK: s_sub_u32 s5, s5, 0x40000
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%a = load volatile i32, i32 addrspace(5)* %aptr
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; Force %a to spill
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call void asm sideeffect "", "~{v0},~{v1},~{v2},~{v3},~{v4},~{v5},~{v6},~{v7}" ()
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%outptr = getelementptr i32, i32 addrspace(5)* %buf, i32 1
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store volatile i32 %a, i32 addrspace(5)* %outptr
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ret void
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}
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; CHECK-LABEL: test_sgpr_offset_subregs_function
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define void @test_sgpr_offset_subregs_function() {
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entry:
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; Occupy 4088 bytes of scratch, so that the spill of the last subreg of %a
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; still fits below offset 4096 (4088 + 8 - 4 = 4092), and can be placed in
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; the instruction offset field.
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%alloca = alloca i8, i32 4084, align 4, addrspace(5)
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%bufv1 = bitcast i8 addrspace(5)* %alloca to i32 addrspace(5)*
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%bufv2 = bitcast i8 addrspace(5)* %alloca to <2 x i32> addrspace(5)*
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s{{[0-9]+}} offset:4088 ; 4-byte Folded Spill
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s{{[0-9]+}} offset:4092 ; 4-byte Folded Spill
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%aptr = getelementptr <2 x i32>, <2 x i32> addrspace(5)* %bufv2, i32 1
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%a = load volatile <2 x i32>, <2 x i32> addrspace(5)* %aptr
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; Force %a to spill.
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call void asm sideeffect "", "~{v0},~{v1},~{v2},~{v3},~{v4},~{v5},~{v6},~{v7}" ()
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; Ensure the alloca sticks around.
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%bptr = getelementptr i32, i32 addrspace(5)* %bufv1, i32 1
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%b = load volatile i32, i32 addrspace(5)* %bptr
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; Ensure the spill is of the full super-reg.
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call void asm sideeffect "; $0", "r"(<2 x i32> %a)
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ret void
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}
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; CHECK-LABEL: test_inst_offset_subregs_function
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define void @test_inst_offset_subregs_function() {
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entry:
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; Occupy 4092 bytes of scratch, so that the spill of the last subreg of %a
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; does not fit below offset 4096 (4092 + 8 - 4 = 4096), and has to live
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; in the SGPR offset.
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%alloca = alloca i8, i32 4088, align 4, addrspace(5)
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%bufv1 = bitcast i8 addrspace(5)* %alloca to i32 addrspace(5)*
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%bufv2 = bitcast i8 addrspace(5)* %alloca to <2 x i32> addrspace(5)*
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; 0x3ff00 / 64 = 4092 (for wave64)
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; CHECK: s_add_u32 s5, s5, 0x3ff00
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s5 ; 4-byte Folded Spill
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; CHECK: buffer_store_dword v{{[0-9]+}}, off, s[{{[0-9]+:[0-9]+}}], s5 offset:4 ; 4-byte Folded Spill
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; CHECK: s_sub_u32 s5, s5, 0x3ff00
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%aptr = getelementptr <2 x i32>, <2 x i32> addrspace(5)* %bufv2, i32 1
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%a = load volatile <2 x i32>, <2 x i32> addrspace(5)* %aptr
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; Force %a to spill.
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call void asm sideeffect "", "~{v0},~{v1},~{v2},~{v3},~{v4},~{v5},~{v6},~{v7}" ()
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; Ensure the alloca sticks around.
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%bptr = getelementptr i32, i32 addrspace(5)* %bufv1, i32 1
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%b = load volatile i32, i32 addrspace(5)* %bptr
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; Ensure the spill is of the full super-reg.
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call void asm sideeffect "; $0", "r"(<2 x i32> %a)
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ret void
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}
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