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[mips] Use the delay slot filler to convert branches for microMIPSR6. 

The MIPS delay slot filler converts delay slot branches into compact
forms for the MIPS ISAs which support them. For branches that compare
(in)equality with with zero, it converts them into branches with implict
zero register operands. These branches have a slightly greater range
than normal two register operands branches.

Changing the branches at this point in the pipeline offers the long
branch pass the ability to mark better judgements if a long branch
sequence is required.

Reviewers: atanasyan

Differential Revision: https://reviews.llvm.org/D40314

llvm-svn: 318908
This commit is contained in:
Simon Dardis 2017-11-23 12:38:04 +00:00
parent 4c488975da
commit eb5bfd9889
4 changed files with 13 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
llvm/lib/Target/Mips/MipsDelaySlotFiller.cpp
View File

@ -597,21 +597,14 @@ bool Filler::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
bool InMicroMipsMode = STI.inMicroMipsMode();
const MipsInstrInfo *TII = STI.getInstrInfo();
if (InMicroMipsMode && STI.hasMips32r6()) {
// This is microMIPS32r6 or microMIPS64r6 processor. Delay slot for
// branching instructions is not needed.
return Changed;
}
for (Iter I = MBB.begin(); I != MBB.end(); ++I) {
if (!hasUnoccupiedSlot(&*I))
continue;
++FilledSlots;
Changed = true;
// Delay slot filling is disabled at -O0, or in microMIPS32R6.
if (!DisableDelaySlotFiller && (TM->getOptLevel() != CodeGenOpt::None) &&
!(InMicroMipsMode && STI.hasMips32r6())) {
// Delay slot filling is disabled at -O0.
if (!DisableDelaySlotFiller && (TM->getOptLevel() != CodeGenOpt::None)) {
bool Filled = false;
if (MipsCompactBranchPolicy.getValue() != CB_Always ||
@ -643,6 +636,8 @@ bool Filler::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
// if it is in range.
DSI->setDesc(TII->get(getEquivalentCallShort(DSI->getOpcode())));
}
++FilledSlots;
Changed = true;
continue;
}
}
@ -660,12 +655,15 @@ bool Filler::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
(STI.hasMips32r6() && MipsCompactBranchPolicy != CB_Never)) &&
TII->getEquivalentCompactForm(I)) {
I = replaceWithCompactBranch(MBB, I, I->getDebugLoc());
Changed = true;
continue;
}
// Bundle the NOP to the instruction with the delay slot.
BuildMI(MBB, std::next(I), I->getDebugLoc(), TII->get(Mips::NOP));
MIBundleBuilder(MBB, I, std::next(I, 2));
++FilledSlots;
Changed = true;
}
return Changed;

8
llvm/test/CodeGen/Mips/fcmp.ll
View File

@ -1100,7 +1100,7 @@ entry:
; MM32R6-DAG: cmp.le.s $[[T3:f[0-9]+]], $[[T0]], $[[T2]]
; MM32R6-DAG: mfc1 $[[T4:[0-9]+]], $[[T3:f[0-9]+]]
; MM32R6-DAG: andi16 $[[T5:[0-9]+]], $[[T4]], 1
; MM32R6-DAG: bnez $[[T5]],
; MM32R6-DAG: bnezc $[[T5]],
; MM64R6-DAG: add.s $[[T0:f[0-9]+]], $f13, $f12
; MM64R6-DAG: lui $[[T1:[0-9]+]], %highest(.LCPI32_0)
@ -1112,7 +1112,7 @@ entry:
; MM64R6-DAG: cmp.le.s $[[T7:f[0-9]+]], $[[T0]], $[[T6]]
; MM64R6-DAG: mfc1 $[[T8:[0-9]+]], $[[T7]]
; MM64R6-DAG: andi16 $[[T9:[0-9]+]], $[[T8]], 1
; MM64R6-DAG: bnez $[[T9]],
; MM64R6-DAG: bnezc $[[T9]],
%add = fadd fast float %at, %angle
%cmp = fcmp ogt float %add, 1.000000e+00
@ -1170,7 +1170,7 @@ entry:
; MM32R6-DAG: cmp.le.d $[[T3:f[0-9]+]], $[[T0]], $[[T2]]
; MM32R6-DAG: mfc1 $[[T4:[0-9]+]], $[[T3]]
; MM32R6-DAG: andi16 $[[T5:[0-9]+]], $[[T4]], 1
; MM32R6-DAG: bnez $[[T5]],
; MM32R6-DAG: bnezc $[[T5]],
; MM64R6-DAG: add.d $[[T0:f[0-9]+]], $f13, $f12
; MM64R6-DAG: lui $[[T1:[0-9]+]], %highest(.LCPI33_0)
@ -1182,7 +1182,7 @@ entry:
; MM64R6-DAG: cmp.le.d $[[T7:f[0-9]+]], $[[T0]], $[[T6]]
; MM64R6-DAG: mfc1 $[[T8:[0-9]+]], $[[T7]]
; MM64R6-DAG: andi16 $[[T9:[0-9]+]], $[[T8]], 1
; MM64R6-DAG: bnez $[[T9]],
; MM64R6-DAG: bnezc $[[T9]],
%add = fadd fast double %at, %angle
%cmp = fcmp ogt double %add, 1.000000e+00

1
llvm/test/CodeGen/Mips/llvm-ir/sub.ll
View File

@ -222,7 +222,6 @@ entry:
; MM64: dsrl $[[T3:[0-9]+]], $[[T2]], 32
; MM64: dsubu $2, $[[T0]], $[[T3]]
; MM64: dsubu $3, $5, $7
; MM64: jr $ra
%r = sub i128 %a, %b
ret i128 %r

2
llvm/test/CodeGen/Mips/tailcall/tailcall.ll
View File

@ -169,7 +169,7 @@ entry:
; STATIC32MMR6: bc
; PIC64: jr $25
; PIC64R6: jrc $25
; PIC64R6MM: jr $25
; PIC64R6MM: jrc $25
; STATIC64: j
; PIC16: jalrc