[polly] r252725 - ScopDetection: Do not allow blocks to reference operands in error blocks

[Tobias Grosser via llvm-commits]

Author: grosser
Date: Wed Nov 11 06:44:18 2015
New Revision: 252725

URL: http://llvm.org/viewvc/llvm-project?rev=252725&view=rev
Log:
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.

Added:
    polly/trunk/test/ScopDetect/error-block-referenced-from-scop.ll
Modified:
    polly/trunk/lib/Analysis/ScopDetection.cpp
    polly/trunk/lib/Support/ScopHelper.cpp

Modified: polly/trunk/lib/Analysis/ScopDetection.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopDetection.cpp?rev=252725&r1=252724&r2=252725&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopDetection.cpp (original)
+++ polly/trunk/lib/Analysis/ScopDetection.cpp Wed Nov 11 06:44:18 2015
@@ -729,6 +729,16 @@ bool ScopDetection::isValidMemoryAccess(
 
 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))

Modified: polly/trunk/lib/Support/ScopHelper.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Support/ScopHelper.cpp?rev=252725&r1=252724&r2=252725&view=diff
==============================================================================
--- polly/trunk/lib/Support/ScopHelper.cpp (original)
+++ polly/trunk/lib/Support/ScopHelper.cpp Wed Nov 11 06:44:18 2015
@@ -368,6 +368,9 @@ bool polly::isErrorBlock(BasicBlock &BB,
 
   for (Instruction &Inst : BB)
     if (CallInst *CI = dyn_cast<CallInst>(&Inst)) {
+      if (isIgnoredIntrinsic(CI))
+        return false;
+
       if (!CI->doesNotAccessMemory())
         return true;
       if (CI->doesNotReturn())

Added: polly/trunk/test/ScopDetect/error-block-referenced-from-scop.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/ScopDetect/error-block-referenced-from-scop.ll?rev=252725&view=auto
==============================================================================
--- polly/trunk/test/ScopDetect/error-block-referenced-from-scop.ll (added)
+++ polly/trunk/test/ScopDetect/error-block-referenced-from-scop.ll Wed Nov 11 06:44:18 2015
@@ -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}