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ScopDetection: Do not allow blocks to reference operands in error blocks 

r252713 introduced a couple of regressions due to later basic blocks refering
to instructions defined in error blocks which have not yet been modeled.

This commit is currently just encoding limitations of our modeling and code
generation backends to ensure correctness. In theory, we should be able to
generate and optimize such regions, as everything that is dominated by an error
region is assumed to not be executed anyhow. We currently just lack the code
to make this happen in practice.

llvm-svn: 252725
This commit is contained in:
Tobias Grosser 2015-11-11 12:44:18 +00:00
parent e76a7c41e9
commit b12b006c4b
3 changed files with 67 additions and 0 deletions
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10
polly/lib/Analysis/ScopDetection.cpp
View File

@ -729,6 +729,16 @@ bool ScopDetection::isValidMemoryAccess(Instruction &Inst,
bool ScopDetection::isValidInstruction(Instruction &Inst,
DetectionContext &Context) const {
for (auto &Op : Inst.operands()) {
auto *OpInst = dyn_cast<Instruction>(&Op);
if (!OpInst)
continue;
if (isErrorBlock(*OpInst->getParent(), Context.CurRegion, *LI, *DT))
return false;
}
// We only check the call instruction but not invoke instruction.
if (CallInst *CI = dyn_cast<CallInst>(&Inst)) {
if (isValidCallInst(*CI))

3
polly/lib/Support/ScopHelper.cpp
View File

@ -368,6 +368,9 @@ bool polly::isErrorBlock(BasicBlock &BB, const Region &R, LoopInfo &LI,
for (Instruction &Inst : BB)
if (CallInst *CI = dyn_cast<CallInst>(&Inst)) {
if (isIgnoredIntrinsic(CI))
return false;
if (!CI->doesNotAccessMemory())
return true;
if (CI->doesNotReturn())

54
polly/test/ScopDetect/error-block-referenced-from-scop.ll Normal file
View File

@ -0,0 +1,54 @@
; RUN: opt %loadPolly -polly-code-generator=isl -polly-detect -analyze < %s \
; RUN: | FileCheck %s
;
; CHECK-NOT: Valid Region for Scop:
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: nounwind uwtable
define void @hoge() #0 {
bb:
br label %bb1
bb1: ; preds = %bb
br i1 undef, label %bb2, label %bb7
bb2: ; preds = %bb1
%tmp = load i32, i32* undef, align 8, !tbaa !1
%tmp3 = tail call i32 @widget() #2
br i1 false, label %bb4, label %bb5
bb4: ; preds = %bb2
br label %bb8
bb5: ; preds = %bb2
%tmp6 = sub i32 %tmp, %tmp3
br label %bb8
bb7: ; preds = %bb1
br label %bb8
bb8: ; preds = %bb7, %bb5, %bb4
ret void
}
; Function Attrs: inlinehint nounwind readonly uwtable
declare i32 @widget() #1
attributes #0 = { nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { inlinehint nounwind readonly uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #2 = { nounwind readonly }
!llvm.ident = !{!0}
!0 = !{!"clang version 3.8.0 (trunk 252700) (llvm/trunk 252705)"}
!1 = !{!2, !7, i64 8}
!2 = !{!"cli_target_info", !3, i64 0, !6, i64 8, !4, i64 32}
!3 = !{!"long", !4, i64 0}
!4 = !{!"omnipotent char", !5, i64 0}
!5 = !{!"Simple C/C++ TBAA"}
!6 = !{!"cli_exe_info", !7, i64 0, !8, i64 4, !3, i64 8, !9, i64 16}
!7 = !{!"int", !4, i64 0}
!8 = !{!"short", !4, i64 0}
!9 = !{!"any pointer", !4, i64 0}