[OPENMP]Support for non-rectangular loops.

Added basic support for non-rectangular loops. It requires an additional
analysis of min/max boundaries for non-rectangular loops. Since only
linear dependency is allowed, we can do this analysis.

llvm-svn: 368903

1 files changed, 30 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index e8fbca5108a..2ca7ebc6b0d 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -1324,6 +1324,16 @@ void CodeGenFunction::EmitOMPLoopBody(const OMPLoopDirective &D,
   // On a continue in the body, jump to the end.
   JumpDest Continue = getJumpDestInCurrentScope("omp.body.continue");
   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
+  for (const Expr *E : D.finals_conditions()) {
+    if (!E)
+      continue;
+    // Check that loop counter in non-rectangular nest fits into the iteration
+    // space.
+    llvm::BasicBlock *NextBB = createBasicBlock("omp.body.next");
+    EmitBranchOnBoolExpr(E, NextBB, Continue.getBlock(),
+                         getProfileCount(D.getBody()));
+    EmitBlock(NextBB);
+  }
   // Emit loop body.
   EmitStmt(D.getBody());
   // The end (updates/cleanups).
@@ -1553,8 +1563,28 @@ static void emitPreCond(CodeGenFunction &CGF, const OMPLoopDirective &S,
       CGF.EmitIgnoredExpr(I);
     }
   }
+  // Create temp loop control variables with their init values to support
+  // non-rectangular loops.
+  CodeGenFunction::OMPMapVars PreCondVars;
+  for (const Expr * E: S.dependent_counters()) {
+    if (!E)
+      continue;
+    assert(!E->getType().getNonReferenceType()->isRecordType() &&
+           "dependent counter must not be an iterator.");
+    const auto *VD = cast<VarDecl>(cast<DeclRefExpr>(E)->getDecl());
+    Address CounterAddr =
+        CGF.CreateMemTemp(VD->getType().getNonReferenceType());
+    (void)PreCondVars.setVarAddr(CGF, VD, CounterAddr);
+  }
+  (void)PreCondVars.apply(CGF);
+  for (const Expr *E : S.dependent_inits()) {
+    if (!E)
+      continue;
+    CGF.EmitIgnoredExpr(E);
+  }
   // Check that loop is executed at least one time.
   CGF.EmitBranchOnBoolExpr(Cond, TrueBlock, FalseBlock, TrueCount);
+  PreCondVars.restore(CGF);
 }
 
 void CodeGenFunction::EmitOMPLinearClause(