AMDGPU: Be explicit about whether the high-word in SI_PC_ADD_REL_OFFSET is 0

Summary:
Instead of encoding a high-word of 0 using a fake TargetGlobalAddress,
just use a literal target constant. This simplifies some subsequent changes.

The generated assembly is now more explicit about the kind of relocation
that is to be used.

Change-Id: I066835202d23b5941fa7a358eb4b89e9b71ab6f8

Reviewers: arsenm, rampitec

Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, t-tye, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61491

llvm-svn: 363516
This commit is contained in:
Nicolai Haehnle 2019-06-16 17:32:01 +00:00
parent 4d4ef2a167
commit 6d71be4e67
5 changed files with 21 additions and 12 deletions

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@ -4644,11 +4644,18 @@ buildPCRelGlobalAddress(SelectionDAG &DAG, const GlobalValue *GV,
// of the s_add_u32 instruction, we end up with an offset that is 4 bytes too
// small. This requires us to add 4 to the global variable offset in order to
// compute the correct address.
SDValue PtrLo = DAG.getTargetGlobalAddress(GV, DL, MVT::i32, Offset + 4,
GAFlags);
SDValue PtrHi = DAG.getTargetGlobalAddress(GV, DL, MVT::i32, Offset + 4,
GAFlags == SIInstrInfo::MO_NONE ?
GAFlags : GAFlags + 1);
unsigned LoFlags = GAFlags;
if (LoFlags == SIInstrInfo::MO_NONE)
LoFlags = SIInstrInfo::MO_REL32;
SDValue PtrLo =
DAG.getTargetGlobalAddress(GV, DL, MVT::i32, Offset + 4, LoFlags);
SDValue PtrHi;
if (GAFlags == SIInstrInfo::MO_NONE) {
PtrHi = DAG.getTargetConstant(0, DL, MVT::i32);
} else {
PtrHi =
DAG.getTargetGlobalAddress(GV, DL, MVT::i32, Offset + 4, GAFlags + 1);
}
return DAG.getNode(AMDGPUISD::PC_ADD_REL_OFFSET, DL, PtrVT, PtrLo, PtrHi);
}

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@ -1369,10 +1369,7 @@ bool SIInstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
MachineInstrBuilder MIB = BuildMI(MF, DL, get(AMDGPU::S_ADDC_U32), RegHi)
.addReg(RegHi);
if (MI.getOperand(2).getTargetFlags() == SIInstrInfo::MO_NONE)
MIB.addImm(0);
else
MIB.add(MI.getOperand(2));
MIB.add(MI.getOperand(2));
Bundler.append(MIB);
finalizeBundle(MBB, Bundler.begin());

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@ -551,10 +551,15 @@ def SI_PC_ADD_REL_OFFSET : SPseudoInstSI <
(outs SReg_64:$dst),
(ins si_ga:$ptr_lo, si_ga:$ptr_hi),
[(set SReg_64:$dst,
(i64 (SIpc_add_rel_offset (tglobaladdr:$ptr_lo), (tglobaladdr:$ptr_hi))))]> {
(i64 (SIpc_add_rel_offset tglobaladdr:$ptr_lo, tglobaladdr:$ptr_hi)))]> {
let Defs = [SCC];
}
def : GCNPat <
(SIpc_add_rel_offset tglobaladdr:$ptr_lo, 0),
(SI_PC_ADD_REL_OFFSET $ptr_lo, (i32 0))
>;
def : GCNPat <
(AMDGPUinit_exec i64:$src),
(SI_INIT_EXEC (as_i64imm $src))

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@ -333,7 +333,7 @@ define amdgpu_kernel void @test_small_memcpy_i64_global_to_global_align16(i64 ad
; FUNC-LABEL: {{^}}test_memcpy_const_string_align4:
; SI: s_getpc_b64
; SI: s_add_u32 s{{[0-9]+}}, s{{[0-9]+}}, hello.align4+20
; SI: s_add_u32 s{{[0-9]+}}, s{{[0-9]+}}, hello.align4@rel32@lo+20
; SI: s_addc_u32
; SI-DAG: s_load_dwordx4
; SI-DAG: s_load_dwordx4

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@ -2,7 +2,7 @@
; RUN: llc -march=amdgcn -mcpu=tonga -filetype=obj < %s | llvm-readobj -r --symbols | FileCheck %s -check-prefix=GCN
; RUN: llc -march=r600 -mcpu=cypress -filetype=obj < %s | llvm-readobj -r --symbols | FileCheck %s -check-prefix=EG
; GCN: R_AMDGPU_REL32 extern_const_addrspace
; GCN: R_AMDGPU_REL32_LO extern_const_addrspace
; EG: R_AMDGPU_ABS32 extern_const_addrspace
; CHECK-DAG: Name: extern_const_addrspace