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Revert "[PowerPC] Extend folding RLWINM + RLWINM to post-RA."

This reverts commit 119ab2181e6ed823849c93d55af8e989c28c9f3c.
This commit is contained in:
Esme-Yi 2020-11-03 16:34:02 +00:00
parent 83e3834a8d
commit f754a1db1b
7 changed files with 26 additions and 174 deletions

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@ -3190,55 +3190,18 @@ bool PPCInstrInfo::convertToImmediateForm(MachineInstr &MI,
return false;
}
// This function tries to combine two RLWINMs. We not only perform such
// optimization in SSA, but also after RA, since some RLWINM is generated after
// RA.
bool PPCInstrInfo::simplifyRotateAndMaskInstr(MachineInstr &MI,
MachineInstr *&ToErase) const {
bool Is64Bit = false;
switch (MI.getOpcode()) {
case PPC::RLWINM:
case PPC::RLWINM_rec:
break;
case PPC::RLWINM8:
case PPC::RLWINM8_rec:
Is64Bit = true;
break;
default:
return false;
}
bool PPCInstrInfo::combineRLWINM(MachineInstr &MI,
MachineInstr **ToErase) const {
MachineRegisterInfo *MRI = &MI.getParent()->getParent()->getRegInfo();
Register FoldingReg = MI.getOperand(1).getReg();
MachineInstr *SrcMI = nullptr;
bool NoUse = false;
if (MRI->isSSA()) {
unsigned FoldingReg = MI.getOperand(1).getReg();
if (!Register::isVirtualRegister(FoldingReg))
return false;
SrcMI = MRI->getVRegDef(FoldingReg);
} else {
bool OtherIntermediateUse = false;
SrcMI = getDefMIPostRA(FoldingReg, MI, OtherIntermediateUse);
NoUse = !OtherIntermediateUse && MI.getOperand(1).isKill();
}
if (!SrcMI)
MachineInstr *SrcMI = MRI->getVRegDef(FoldingReg);
if (SrcMI->getOpcode() != PPC::RLWINM &&
SrcMI->getOpcode() != PPC::RLWINM_rec &&
SrcMI->getOpcode() != PPC::RLWINM8 &&
SrcMI->getOpcode() != PPC::RLWINM8_rec)
return false;
// TODO: The pairs of RLWINM8(RLWINM) or RLWINM(RLWINM8) never occur before
// RA, but after RA. And We can fold RLWINM8(RLWINM) -> RLWINM8, or
// RLWINM(RLWINM8) -> RLWINM.
switch (SrcMI->getOpcode()) {
case PPC::RLWINM:
case PPC::RLWINM_rec:
if (Is64Bit)
return false;
break;
case PPC::RLWINM8:
case PPC::RLWINM8_rec:
if (!Is64Bit)
return false;
break;
default:
return false;
}
assert((MI.getOperand(2).isImm() && MI.getOperand(3).isImm() &&
MI.getOperand(4).isImm() && SrcMI->getOperand(2).isImm() &&
SrcMI->getOperand(3).isImm() && SrcMI->getOperand(4).isImm()) &&
@ -3293,6 +3256,8 @@ bool PPCInstrInfo::simplifyRotateAndMaskInstr(MachineInstr &MI,
// If final mask is 0, MI result should be 0 too.
if (FinalMask.isNullValue()) {
bool Is64Bit =
(MI.getOpcode() == PPC::RLWINM8 || MI.getOpcode() == PPC::RLWINM8_rec);
Simplified = true;
LLVM_DEBUG(dbgs() << "Replace Instr: ");
LLVM_DEBUG(MI.dump());
@ -3350,16 +3315,15 @@ bool PPCInstrInfo::simplifyRotateAndMaskInstr(MachineInstr &MI,
LLVM_DEBUG(dbgs() << "To: ");
LLVM_DEBUG(MI.dump());
}
if (Simplified && !SrcMI->hasImplicitDef()) {
// If SrcMI has no implicit def, and FoldingReg has no non-debug use or
// its flag is "killed", it's safe to delete SrcMI. Otherwise keep it.
if ((!MRI->isSSA() && NoUse) ||
(MRI->isSSA() && MRI->use_nodbg_empty(FoldingReg))) {
ToErase = SrcMI;
if (Simplified & MRI->use_nodbg_empty(FoldingReg) &&
!SrcMI->hasImplicitDef()) {
// If FoldingReg has no non-debug use and it has no implicit def (it
// is not RLWINMO or RLWINM8o), it's safe to delete its def SrcMI.
// Otherwise keep it.
*ToErase = SrcMI;
LLVM_DEBUG(dbgs() << "Delete dead instruction: ");
LLVM_DEBUG(SrcMI->dump());
}
}
return Simplified;
}

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@ -564,8 +564,7 @@ public:
bool convertToImmediateForm(MachineInstr &MI,
MachineInstr **KilledDef = nullptr) const;
bool foldFrameOffset(MachineInstr &MI) const;
bool simplifyRotateAndMaskInstr(MachineInstr &MI,
MachineInstr *&ToErase) const;
bool combineRLWINM(MachineInstr &MI, MachineInstr **ToErase = nullptr) const;
bool isADDIInstrEligibleForFolding(MachineInstr &ADDIMI, int64_t &Imm) const;
bool isADDInstrEligibleForFolding(MachineInstr &ADDMI) const;
bool isImmInstrEligibleForFolding(MachineInstr &MI, unsigned &BaseReg,

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@ -848,7 +848,7 @@ bool PPCMIPeephole::simplifyCode(void) {
case PPC::RLWINM_rec:
case PPC::RLWINM8:
case PPC::RLWINM8_rec: {
Simplified = TII->simplifyRotateAndMaskInstr(MI, ToErase);
Simplified = TII->combineRLWINM(MI, &ToErase);
if (Simplified)
++NumRotatesCollapsed;
break;

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@ -37,8 +37,6 @@ STATISTIC(NumberOfSelfCopies,
"Number of self copy instructions eliminated");
STATISTIC(NumFrameOffFoldInPreEmit,
"Number of folding frame offset by using r+r in pre-emit peephole");
STATISTIC(NumRotateInstrFoldInPreEmit,
"Number of folding Rotate instructions in pre-emit peephole");
static cl::opt<bool>
EnablePCRelLinkerOpt("ppc-pcrel-linker-opt", cl::Hidden, cl::init(true),
@ -415,13 +413,6 @@ static bool hasPCRelativeForm(MachineInstr &Use) {
LLVM_DEBUG(dbgs() << "Frame offset folding by using index form: ");
LLVM_DEBUG(MI.dump());
}
MachineInstr *ToErase = nullptr;
if (TII->simplifyRotateAndMaskInstr(MI, ToErase)) {
Changed = true;
NumRotateInstrFoldInPreEmit++;
if (ToErase)
InstrsToErase.push_back(ToErase);
}
}
// Eliminate conditional branch based on a constant CR bit by

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@ -1,104 +0,0 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -mcpu=pwr9 -mtriple=powerpc64le-unknown-unknown -stop-after \
# RUN: ppc-pre-emit-peephole %s -o - | FileCheck %s
---
name: testFoldRLWINM
tracksRegLiveness: true
body: |
bb.0.entry:
liveins: $r3
; CHECK-LABEL: name: testFoldRLWINM
; CHECK: liveins: $r3
; CHECK: renamable $r3 = RLWINM killed renamable $r3, 14, 0, 12, implicit-def $x3
; CHECK: BLR8 implicit $lr8, implicit $rm, implicit killed $x3
$r3 = RLWINM killed $r3, 27, 5, 31
dead renamable $r3 = RLWINM killed renamable $r3, 19, 0, 12, implicit-def $x3
BLR8 implicit $lr8, implicit $rm, implicit killed $x3
...
---
name: testFoldRLWINMSrcFullMask
tracksRegLiveness: true
body: |
bb.0.entry:
liveins: $r3
; CHECK-LABEL: name: testFoldRLWINMSrcFullMask
; CHECK: liveins: $r3
; CHECK: renamable $r3 = RLWINM killed renamable $r3, 14, 0, 12, implicit-def $x3
; CHECK: BLR8 implicit $lr8, implicit $rm, implicit killed $x3
$r3 = RLWINM killed $r3, 27, 0, 31
dead renamable $r3 = RLWINM killed renamable $r3, 19, 0, 12, implicit-def $x3
BLR8 implicit $lr8, implicit $rm, implicit killed $x3
...
---
name: testFoldRLWINMSrcWrapped
tracksRegLiveness: true
body: |
bb.0.entry:
liveins: $r3
; CHECK-LABEL: name: testFoldRLWINMSrcWrapped
; CHECK: liveins: $r3
; CHECK: renamable $r3 = RLWINM killed renamable $r3, 14, 11, 12, implicit-def $x3
; CHECK: BLR8 implicit $lr8, implicit $rm, implicit killed $x3
$r3 = RLWINM killed $r3, 27, 30, 10
dead renamable $r3 = RLWINM killed renamable $r3, 19, 0, 12, implicit-def $x3
BLR8 implicit $lr8, implicit $rm, implicit killed $x3
...
---
name: testFoldRLWINMToZero
tracksRegLiveness: true
body: |
bb.0.entry:
liveins: $r3
; CHECK-LABEL: name: testFoldRLWINMToZero
; CHECK: liveins: $r3
; CHECK: renamable $r3 = LI 0, implicit-def $x3
; CHECK: BLR8 implicit $lr8, implicit $rm, implicit killed $x3
$r3 = RLWINM killed $r3, 27, 5, 10
dead renamable $r3 = RLWINM killed renamable $r3, 8, 5, 10, implicit-def $x3
BLR8 implicit $lr8, implicit $rm, implicit killed $x3
...
---
name: testFoldRLWINM_recToZero
tracksRegLiveness: true
body: |
bb.0.entry:
liveins: $r3
; CHECK-LABEL: name: testFoldRLWINM_recToZero
; CHECK: liveins: $r3
; CHECK: dead renamable $r3 = ANDI_rec killed renamable $r3, 0, implicit-def $cr0
; CHECK: BLR8 implicit $lr8, implicit $rm, implicit killed $cr0
$r3 = RLWINM killed $r3, 27, 5, 10
dead renamable $r3 = RLWINM_rec killed renamable $r3, 8, 5, 10, implicit-def $cr0
BLR8 implicit $lr8, implicit $rm, implicit killed $cr0
...
---
name: testFoldRLWINMoToZeroSrcCanNotBeDeleted
tracksRegLiveness: true
body: |
bb.0.entry:
liveins: $r3
; CHECK-LABEL: name: testFoldRLWINMoToZeroSrcCanNotBeDeleted
; CHECK: liveins: $r3
; CHECK: $r3 = RLWINM_rec $r3, 27, 5, 10, implicit-def dead $cr0
; CHECK: dead renamable $r3 = ANDI_rec killed renamable $r3, 0, implicit-def $cr0
; CHECK: BLR8 implicit $lr8, implicit $rm, implicit killed $cr0
$r3 = RLWINM_rec $r3, 27, 5, 10, implicit-def $cr0
dead renamable $r3 = RLWINM_rec killed renamable $r3, 8, 5, 10, implicit-def $cr0
BLR8 implicit $lr8, implicit $rm, implicit killed $cr0
...
---
name: testFoldRLWINMInvalidMask
tracksRegLiveness: true
body: |
bb.0.entry:
liveins: $r3
; CHECK-LABEL: name: testFoldRLWINMInvalidMask
; CHECK: liveins: $r3
; CHECK: $r3 = RLWINM killed $r3, 20, 5, 31
; CHECK: renamable $r3 = RLWINM killed renamable $r3, 19, 10, 20, implicit-def $x3
; CHECK: BLR8 implicit $lr8, implicit $rm, implicit killed $x3
$r3 = RLWINM killed $r3, 20, 5, 31
dead renamable $r3 = RLWINM killed renamable $r3, 19, 10, 20, implicit-def $x3
BLR8 implicit $lr8, implicit $rm, implicit killed $x3
...

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@ -14,8 +14,9 @@ define void @phi5() unnamed_addr {
; CHECK-NEXT: # %bb.2:
; CHECK-NEXT: lhz 3, 0(3)
; CHECK-NEXT: slwi 3, 3, 15
; CHECK-NEXT: li 4, 0
; CHECK-NEXT: ori 3, 4, 0
; CHECK-NEXT: clrlwi 3, 3, 31
; CHECK-NEXT: rlwinm 4, 3, 31, 17, 31
; CHECK-NEXT: or 3, 3, 4
; CHECK-NEXT: rlwimi 3, 3, 15, 0, 16
; CHECK-NEXT: # %bb.3:
; CHECK-NEXT: blr

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@ -131,7 +131,8 @@ define i32 @xvtdivdp_shift(<2 x double> %a, <2 x double> %b) {
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: xvtdivdp cr0, v2, v3
; CHECK-NEXT: mfocrf r3, 128
; CHECK-NEXT: li r3, 0
; CHECK-NEXT: srwi r3, r3, 28
; CHECK-NEXT: rlwinm r3, r3, 28, 31, 31
; CHECK-NEXT: blr
entry:
%0 = tail call i32 @llvm.ppc.vsx.xvtdivdp(<2 x double> %a, <2 x double> %b)