Commit 339b39b7 authored by Anton Afanasyev's avatar Anton Afanasyev
Browse files

[MIR] Skip hoisting to basic block which may throw exception or return 

Summary:
Fix hoisting to basic block which are not legal for hoisting cause
it can be terminated by exception or it is return block.

Reviewers: john.brawn, RKSimon, MatzeB

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63148

llvm-svn: 363164
parent 082a4199

llvm/lib/CodeGen/MachineCSE.cpp

+2 −0
Original line number Diff line number Diff line
@@ -799,6 +799,8 @@ bool MachineCSE::ProcessBlockPRE(MachineDominatorTree *DT, 
        !DT->properlyDominates(MBB, MBB1) &&

        "MBB cannot properly dominate MBB1 while DFS through dominators tree!");

    auto CMBB = DT->findNearestCommonDominator(MBB, MBB1);

    if (!CMBB->isLegalToHoistInto())

      continue;



    // Two instrs are partial redundant if their basic blocks are reachable

    // from one to another but one doesn't dominate another.

llvm/test/CodeGen/AArch64/machine_cse_illegal_hoist.ll

0 → 100644
+52 −0
Original line number Diff line number Diff line 
; RUN: llc -O3 < %s | FileCheck %s

;

;  Check ADRP instr is not hoisted to entry basic block

;  which may throw exception.

;

; CHECK: adrp

; CHECK: adrp

; CHECK: adrp



target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"

target triple = "aarch64-arm-none-eabi"



@var = hidden local_unnamed_addr global i32 0, align 4

@_ZTIi = external dso_local constant i8*

declare dso_local void @_Z2fnv() local_unnamed_addr #1

declare dso_local i32 @__gxx_personality_v0(...)

declare i32 @llvm.eh.typeid.for(i8*) #2

declare dso_local i8* @__cxa_begin_catch(i8*) local_unnamed_addr

declare dso_local void @__cxa_end_catch() local_unnamed_addr



define hidden i32 @_Z7examplev() personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {

entry:

  invoke void @_Z2fnv() to label %try.cont unwind label %lpad



lpad:                                             ; preds = %entry

  %0 = landingpad { i8*, i32 }

          catch i8* bitcast (i8** @_ZTIi to i8*)

          catch i8* null

  %1 = extractvalue { i8*, i32 } %0, 0

  %2 = extractvalue { i8*, i32 } %0, 1

  %3 = tail call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))

  %matches = icmp eq i32 %2, %3

  %4 = tail call i8* @__cxa_begin_catch(i8* %1)

  %5 = load i32, i32* @var, align 4

  br i1 %matches, label %catch1, label %catch



catch1:                                           ; preds = %lpad

  %or3 = or i32 %5, 4

  store i32 %or3, i32* @var, align 4

  tail call void @__cxa_end_catch()

  br label %try.cont



try.cont:                                         ; preds = %entry, %catch1, %catch

  %6 = load i32, i32* @var, align 4

  ret i32 %6



catch:                                            ; preds = %lpad

  %or = or i32 %5, 8

  store i32 %or, i32* @var, align 4

  tail call void @__cxa_end_catch()

  br label %try.cont

}