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Also add <imp-def> operands for defined and dead super-registers when rewriting. 

We cannot rely on the <imp-def> operands added by LiveIntervals in all cases as
demonstrated by the test case.

llvm-svn: 130313
This commit is contained in:
Jakob Stoklund Olesen 2011-04-27 17:42:31 +00:00
parent f2752a3938
commit 71d3b895ba
2 changed files with 39 additions and 7 deletions
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21
llvm/lib/CodeGen/VirtRegMap.cpp
View File

@ -260,6 +260,8 @@ void VirtRegMap::rewrite(SlotIndexes *Indexes) {
<< "********** Function: "
<< MF->getFunction()->getName() << '\n');
DEBUG(dump());
SmallVector<unsigned, 8> SuperDeads;
SmallVector<unsigned, 8> SuperDefs;
SmallVector<unsigned, 8> SuperKills;
for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end();
@ -283,12 +285,13 @@ void VirtRegMap::rewrite(SlotIndexes *Indexes) {
if (MO.getSubReg()) {
// A virtual register kill refers to the whole register, so we may
// have to add <imp-use,kill> operands for the super-register.
if (MO.isUse() && MO.isKill() && !MO.isUndef())
SuperKills.push_back(PhysReg);
// We don't have to deal with sub-register defs because
// LiveIntervalAnalysis already added the necessary <imp-def>
// operands.
if (MO.isUse()) {
if (MO.isKill() && !MO.isUndef())
SuperKills.push_back(PhysReg);
} else if (MO.isDead())
SuperDeads.push_back(PhysReg);
else
SuperDefs.push_back(PhysReg);
// PhysReg operands cannot have subregister indexes.
PhysReg = TRI->getSubReg(PhysReg, MO.getSubReg());
@ -305,6 +308,12 @@ void VirtRegMap::rewrite(SlotIndexes *Indexes) {
while (!SuperKills.empty())
MI->addRegisterKilled(SuperKills.pop_back_val(), TRI, true);
while (!SuperDeads.empty())
MI->addRegisterDead(SuperDeads.pop_back_val(), TRI, true);
while (!SuperDefs.empty())
MI->addRegisterDefined(SuperDefs.pop_back_val(), TRI);
DEBUG(dbgs() << "> " << *MI);
// Finally, remove any identity copies.

25
llvm/test/CodeGen/ARM/crash-greedy.ll
View File

@ -1,4 +1,4 @@
; RUN: llc < %s -regalloc=greedy -mcpu=cortex-a8 -relocation-model=pic -disable-fp-elim | FileCheck %s
; RUN: llc < %s -regalloc=greedy -mcpu=cortex-a8 -relocation-model=pic -disable-fp-elim -verify-machineinstrs | FileCheck %s
;
; ARM tests that crash or fail with the greedy register allocator.
@ -59,3 +59,26 @@ for.end: ; preds = %cond.end
ret void
}
; CHECK: insert_elem
; This test has a sub-register copy with a kill flag:
; %vreg6:ssub_3<def> = COPY %vreg6:ssub_2<kill>; QPR_VFP2:%vreg6
; The rewriter must do something sensible with that, or the scavenger crashes.
define void @insert_elem() nounwind {
entry:
br i1 undef, label %if.end251, label %if.then84
if.then84: ; preds = %entry
br i1 undef, label %if.end251, label %if.then195
if.then195: ; preds = %if.then84
%div = fdiv float 1.000000e+00, undef
%vecinit207 = insertelement <4 x float> undef, float %div, i32 1
%vecinit208 = insertelement <4 x float> %vecinit207, float 1.000000e+00, i32 2
%vecinit209 = insertelement <4 x float> %vecinit208, float 1.000000e+00, i32 3
%mul216 = fmul <4 x float> zeroinitializer, %vecinit209
store <4 x float> %mul216, <4 x float>* undef, align 16
br label %if.end251
if.end251: ; preds = %if.then195, %if.then84, %entry
ret void
}