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[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
This commit is contained in:
Anton Afanasyev 2019-06-12 13:51:44 +00:00
parent 082a41994a
commit 339b39b773
2 changed files with 54 additions and 0 deletions
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2
llvm/lib/CodeGen/MachineCSE.cpp
View File

@ -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.

52
llvm/test/CodeGen/AArch64/machine_cse_illegal_hoist.ll Normal file
View File

@ -0,0 +1,52 @@
; 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
}