[polly] r287271 - [NFC] Add flag to disable error block assumptions

[Johannes Doerfert via llvm-commits]

Author: jdoerfert
Date: Thu Nov 17 16:16:35 2016
New Revision: 287271

URL: http://llvm.org/viewvc/llvm-project?rev=287271&view=rev
Log:
[NFC] Add flag to disable error block assumptions

The declaration as an "error block" is currently aggressive and not very
smart. This patch allows to disable error blocks completely. This might
be useful to prevent SCoP expansion to a point where the assumed context
becomes infeasible, thus the SCoP has to be discarded.

Modified:
    polly/trunk/lib/Support/ScopHelper.cpp

Modified: polly/trunk/lib/Support/ScopHelper.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Support/ScopHelper.cpp?rev=287271&r1=287270&r2=287271&view=diff
==============================================================================
--- polly/trunk/lib/Support/ScopHelper.cpp (original)
+++ polly/trunk/lib/Support/ScopHelper.cpp Thu Nov 17 16:16:35 2016
@@ -30,6 +30,11 @@ using namespace polly;
 
 #define DEBUG_TYPE "polly-scop-helper"
 
+static cl::opt<bool> PollyAllowErrorBlocks(
+    "polly-allow-error-blocks",
+    cl::desc("Allow to speculate on the execution of 'error blocks'."),
+    cl::Hidden, cl::init(true), cl::ZeroOrMore, cl::cat(PollyCategory));
+
 bool polly::hasInvokeEdge(const PHINode *PN) {
   for (unsigned i = 0, e = PN->getNumIncomingValues(); i < e; ++i)
     if (InvokeInst *II = dyn_cast<InvokeInst>(PN->getIncomingValue(i)))
@@ -372,6 +377,8 @@ Value *polly::expandCodeFor(Scop &S, Sca
 
 bool polly::isErrorBlock(BasicBlock &BB, const Region &R, LoopInfo &LI,
                          const DominatorTree &DT) {
+  if (!PollyAllowErrorBlocks)
+    return false;
 
   if (isa<UnreachableInst>(BB.getTerminator()))
     return true;