[Acc] Fix for PR33208

During codegen, Polly attempts to clear all loops from ScalarEvolution
and LoopInfo, and it does so one block at a time. This causes undefined
behaviour, since this way a loop header might be removed from a loop
before the entire loop is erased, causing ScalarEvolution to run into an
error.

Instead, just delete the entire loop atomically. This fixes currently
failing testcases.

llvm-svn: 326643

1 files changed, 5 insertions, 9 deletions

diff --git a/polly/lib/CodeGen/PPCGCodeGeneration.cpp b/polly/lib/CodeGen/PPCGCodeGeneration.cpp
index 5bf31e60e92..2366b5ec2f8 100644
--- a/polly/lib/CodeGen/PPCGCodeGeneration.cpp
+++ b/polly/lib/CodeGen/PPCGCodeGeneration.cpp
@@ -1555,20 +1555,16 @@ void GPUNodeBuilder::clearDominators(Function *F) {
 }
 
 void GPUNodeBuilder::clearScalarEvolution(Function *F) {
-  for (BasicBlock &BB : *F) {
-    Loop *L = LI.getLoopFor(&BB);
+  for (auto *L : LI)
     if (L)
       SE.forgetLoop(L);
-  }
 }
 
 void GPUNodeBuilder::clearLoops(Function *F) {
-  for (BasicBlock &BB : *F) {
-    Loop *L = LI.getLoopFor(&BB);
-    if (L)
-      SE.forgetLoop(L);
-    LI.removeBlock(&BB);
-  }
+  clearScalarEvolution(F);
+  SmallVector<Loop *, 1> Loops(LI.begin(), LI.end());
+  for (auto *L : Loops)
+    LI.erase(L);
 }
 
 std::tuple<Value *, Value *> GPUNodeBuilder::getGridSizes(ppcg_kernel *Kernel) {