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Fix a bug when hoist spill to a BB with landingpad successor. 

This is to fix the bug in https://llvm.org/bugs/show_bug.cgi?id=27612.

When spill is hoisted to a BB with landingpad successor, and if the VNI
of the spill reg lives into the landingpad successor, the spill should be
inserted before the call which may throw exception. InsertPointAnalysis
is used to compute the safe insert point.

http://reviews.llvm.org/D20027 is a preparing patch for this patch.

Differential Revision: http://reviews.llvm.org/D19884.

llvm-svn: 269249
This commit is contained in:
Wei Mi 2016-05-11 22:37:43 +00:00
parent 35ee9339a8
commit 8c4136b0d8
2 changed files with 72 additions and 6 deletions
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16
llvm/lib/CodeGen/InlineSpiller.cpp
View File

@ -13,6 +13,7 @@
//===----------------------------------------------------------------------===//
#include "Spiller.h"
#include "SplitKit.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Statistic.h"
@ -69,6 +70,8 @@ class HoistSpillHelper : private LiveRangeEdit::Delegate {
const TargetRegisterInfo &TRI;
const MachineBlockFrequencyInfo &MBFI;
InsertPointAnalysis IPA;
// Map from StackSlot to its original register.
DenseMap<int, unsigned> StackSlotToReg;
// Map from pair of (StackSlot and Original VNI) to a set of spills which
@ -114,7 +117,8 @@ public:
MFI(*mf.getFrameInfo()), MRI(mf.getRegInfo()),
TII(*mf.getSubtarget().getInstrInfo()),
TRI(*mf.getSubtarget().getRegisterInfo()),
MBFI(pass.getAnalysis<MachineBlockFrequencyInfo>()) {}
MBFI(pass.getAnalysis<MachineBlockFrequencyInfo>()),
IPA(LIS, mf.getNumBlockIDs()) {}
void addToMergeableSpills(MachineInstr *Spill, int StackSlot,
unsigned Original);
@ -1075,7 +1079,7 @@ bool HoistSpillHelper::rmFromMergeableSpills(MachineInstr *Spill,
bool HoistSpillHelper::isSpillCandBB(unsigned OrigReg, VNInfo &OrigVNI,
MachineBasicBlock &BB, unsigned &LiveReg) {
SlotIndex Idx;
MachineBasicBlock::iterator MI = BB.getFirstTerminator();
MachineBasicBlock::iterator MI = IPA.getLastInsertPointIter(BB);
if (MI != BB.end())
Idx = LIS.getInstructionIndex(*MI);
else
@ -1376,6 +1380,8 @@ void HoistSpillHelper::hoistAllSpills() {
for (auto &Ent : MergeableSpills) {
int Slot = Ent.first.first;
unsigned OrigReg = SlotToOrigReg[Slot];
LiveInterval &OrigLI = LIS.getInterval(OrigReg);
IPA.setInterval(&OrigLI);
VNInfo *OrigVNI = Ent.first.second;
SmallPtrSet<MachineInstr *, 16> &EqValSpills = Ent.second;
if (Ent.second.empty())
@ -1408,17 +1414,15 @@ void HoistSpillHelper::hoistAllSpills() {
// Stack live range update.
LiveInterval &StackIntvl = LSS.getInterval(Slot);
if (!SpillsToIns.empty() || !SpillsToRm.empty()) {
LiveInterval &OrigLI = LIS.getInterval(OrigReg);
if (!SpillsToIns.empty() || !SpillsToRm.empty())
StackIntvl.MergeValueInAsValue(OrigLI, OrigVNI,
StackIntvl.getValNumInfo(0));
}
// Insert hoisted spills.
for (auto const Insert : SpillsToIns) {
MachineBasicBlock *BB = Insert.first;
unsigned LiveReg = Insert.second;
MachineBasicBlock::iterator MI = BB->getFirstTerminator();
MachineBasicBlock::iterator MI = IPA.getLastInsertPointIter(*BB);
TII.storeRegToStackSlot(*BB, MI, LiveReg, false, Slot,
MRI.getRegClass(LiveReg), &TRI);
LIS.InsertMachineInstrRangeInMaps(std::prev(MI), MI);

62
llvm/test/CodeGen/X86/hoist-spill-lpad.ll Normal file
View File

@ -0,0 +1,62 @@
; RUN: llc < %s | FileCheck %s
;
; PR27612. The following spill is hoisted from two locations: the fall
; through succ block and the landingpad block of a call which may throw
; exception. If it is not hoisted before the call, the spill will be
; missing on the landingpad path.
;
; CHECK-LABEL: _Z3foov:
; CHECK: movq %rbx, (%rsp) # 8-byte Spill
; CHECK-NEXT: callq _Z3goov
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@a = global [20 x i64] zeroinitializer, align 16
@_ZTIi = external constant i8*
; Function Attrs: uwtable
define void @_Z3foov() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
entry:
%tmp = load i64, i64* getelementptr inbounds ([20 x i64], [20 x i64]* @a, i64 0, i64 1), align 8
invoke void @_Z3goov()
to label %try.cont unwind label %lpad
lpad: ; preds = %entry
%tmp1 = landingpad { i8*, i32 }
cleanup
catch i8* bitcast (i8** @_ZTIi to i8*)
%tmp2 = extractvalue { i8*, i32 } %tmp1, 1
%tmp3 = tail call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
%matches = icmp eq i32 %tmp2, %tmp3
br i1 %matches, label %catch, label %ehcleanup
catch: ; preds = %lpad
%tmp4 = extractvalue { i8*, i32 } %tmp1, 0
%tmp5 = tail call i8* @__cxa_begin_catch(i8* %tmp4)
store i64 %tmp, i64* getelementptr inbounds ([20 x i64], [20 x i64]* @a, i64 0, i64 2), align 16
tail call void asm sideeffect "", "~{rax},~{rbx},~{rcx},~{rdx},~{rsi},~{rdi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{memory},~{dirflag},~{fpsr},~{flags}"()
store i64 %tmp, i64* getelementptr inbounds ([20 x i64], [20 x i64]* @a, i64 0, i64 3), align 8
tail call void @__cxa_end_catch()
br label %try.cont
try.cont: ; preds = %catch, %entry
store i64 %tmp, i64* getelementptr inbounds ([20 x i64], [20 x i64]* @a, i64 0, i64 4), align 16
tail call void asm sideeffect "", "~{rax},~{rbx},~{rcx},~{rdx},~{rsi},~{rdi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{memory},~{dirflag},~{fpsr},~{flags}"()
store i64 %tmp, i64* getelementptr inbounds ([20 x i64], [20 x i64]* @a, i64 0, i64 5), align 8
ret void
ehcleanup: ; preds = %lpad
resume { i8*, i32 } %tmp1
}
declare void @_Z3goov()
declare i32 @__gxx_personality_v0(...)
; Function Attrs: nounwind readnone
declare i32 @llvm.eh.typeid.for(i8*)
declare i8* @__cxa_begin_catch(i8*)
declare void @__cxa_end_catch()