maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[CodeGen] Skip over dbg-instr in twoaddr pass 

A DBG_VALUE between a two-address instruction and a following COPY
would prevent rescheduleMIBelowKill optimization inside
TwoAddressInstructionPass.

Differential Revision: https://reviews.llvm.org/D55987

llvm-svn: 350289
This commit is contained in:
Markus Lavin 2019-01-03 08:36:06 +00:00
parent 74e7d26090
commit 72b9deb21f
2 changed files with 33 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
View File

@ -929,9 +929,12 @@ rescheduleMIBelowKill(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator Begin = MI;
MachineBasicBlock::iterator AfterMI = std::next(Begin);
MachineBasicBlock::iterator End = AfterMI;
while (End->isCopy() &&
regOverlapsSet(Defs, End->getOperand(1).getReg(), TRI)) {
Defs.push_back(End->getOperand(0).getReg());
while (End != MBB->end()) {
End = skipDebugInstructionsForward(End, MBB->end());
if (End->isCopy() && regOverlapsSet(Defs, End->getOperand(1).getReg(), TRI))
Defs.push_back(End->getOperand(0).getReg());
else
break;
++End;
}

27
llvm/test/CodeGen/X86/twoaddr-dbg-value.mir Normal file
View File

@ -0,0 +1,27 @@
# RUN: llc -run-pass=livevars,twoaddressinstruction -mtriple=x86_64-- -o - %s | FileCheck %s
---
name: foo
tracksRegLiveness: true
body: |
bb.0:
liveins: $edi
%0:gr32 = COPY killed $edi
%1:gr32 = COPY killed %0
%4:gr32 = XOR32ri8 %1, 1, implicit-def dead $eflags
DBG_VALUE %4
%5:gr32 = COPY %4
PUSH32r killed %1, implicit-def $esp, implicit $esp
$eax = COPY killed %5
RETQ implicit killed $eax
...
# Verify that the DBG_VALUE instruction does not inhibit
# TwoAddressInstructionPass::rescheduleMIBelowKill optimization
# CHECK: PUSH32r %1, implicit-def $esp, implicit $esp
# CHECK-NEXT: %2:gr32 = COPY killed %1
# CHECK-NEXT: %2:gr32 = XOR32ri8 %2, 1, implicit-def dead $eflags
# CHECK-NEXT: DBG_VALUE %2
# CHECK-NEXT: %3:gr32 = COPY killed %2