Support SCoPs with multiple entry edges.
Regions that have multiple entry edges are very common. A simple if condition
yields e.g. such a region:
if
/ \
then else
\ /
for_region
This for_region contains two entry edges 'then' -> 'for_region' and 'else' -> 'for_region'.
Previously we scheduled the RegionSimplify pass to translate such regions into
simple regions. With this patch, we now support them natively when the region is
in -loop-simplify form, which means the entry block should not be a loop header.
Contributed by: Star Tan <tanmx_star@yeah.net>
llvm-svn: 179586
diff --git a/polly/lib/Support/ScopHelper.cpp b/polly/lib/Support/ScopHelper.cpp
index 904492a..118bd64 100644
--- a/polly/lib/Support/ScopHelper.cpp
+++ b/polly/lib/Support/ScopHelper.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "polly/Support/ScopHelper.h"
+#include "polly/ScopInfo.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/RegionInfo.h"
@@ -86,6 +87,32 @@
return SplitBlockPredecessors(BB, Preds, ".region", P);
}
+void polly::simplifyRegion(Scop *S, Pass *P){
+ Region *R = &S->getRegion();
+
+ // Create single entry edge if the region has multiple entry edges.
+ if (!R->getEnteringBlock()){
+ BasicBlock *OldEntry = R->getEntry();
+ BasicBlock *NewEntry = SplitBlock (OldEntry, OldEntry->begin(), P);
+
+ for (Scop::iterator SI = S->begin(), SE = S->end(); SI != SE; ++SI)
+ if ((*SI)->getBasicBlock() == OldEntry) {
+ (*SI)->setBasicBlock(NewEntry);
+ break;
+ }
+
+ R->replaceEntryRecursive(NewEntry);
+ }
+
+ // Create single exit edge if the region has multiple exit edges.
+ if (!R->getExitingBlock()) {
+ BasicBlock *NewExit = createSingleExitEdge(R, P);
+
+ for (Region::const_iterator RI = R->begin(), RE = R->end(); RI != RE; ++RI)
+ (*RI)->replaceExitRecursive(NewExit);
+ }
+}
+
void polly::splitEntryBlockForAlloca(BasicBlock *EntryBlock, Pass *P) {
// Find first non-alloca instruction. Every basic block has a non-alloc
// instruction, as every well formed basic block has a terminator.