[OPENMP]Make the loop with unsigned counter countable.

According to the report, better to keep the original strict compare
operation as the loop condition with unsigned loop counters to make the
loop countable. This allows further loop transformations.

llvm-svn: 352526

diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index 0a46543c3a5bf20f565b2cc572c6b58c1a37738d..4a0da35549206d7c4bf47980870265a897dfb441 100644 (file)
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -4008,6 +4008,8 @@ public:
   SourceRange getIncrementSrcRange() const { return IncrementSrcRange; }
   /// True if the step should be subtracted.
   bool shouldSubtractStep() const { return SubtractStep; }
+  /// True, if the compare operator is strict (<, > or !=).
+  bool isStrictTestOp() const { return TestIsStrictOp; }
   /// Build the expression to calculate the number of iterations.
   Expr *buildNumIterations(
       Scope *S, const bool LimitedType,
@@ -4080,7 +4082,8 @@ bool OpenMPIterationSpaceChecker::setLCDeclAndLB(ValueDecl *NewLCDecl,
   return false;
 }
 
-bool OpenMPIterationSpaceChecker::setUB(Expr *NewUB, llvm::Optional<bool> LessOp,
+bool OpenMPIterationSpaceChecker::setUB(Expr *NewUB,
+                                        llvm::Optional<bool> LessOp,
                                         bool StrictOp, SourceRange SR,
                                         SourceLocation SL) {
   // State consistency checking to ensure correct usage.
@@ -4647,10 +4650,12 @@ Expr *OpenMPIterationSpaceChecker::buildOrderedLoopData(
   if (VarType->isIntegerType() || VarType->isPointerType() ||
       SemaRef.getLangOpts().CPlusPlus) {
     // Upper - Lower
-    Expr *Upper =
-        TestIsLessOp.getValue() ? Cnt : tryBuildCapture(SemaRef, UB, Captures).get();
-    Expr *Lower =
-        TestIsLessOp.getValue() ? tryBuildCapture(SemaRef, LB, Captures).get() : Cnt;
+    Expr *Upper = TestIsLessOp.getValue()
+                      ? Cnt
+                      : tryBuildCapture(SemaRef, UB, Captures).get();
+    Expr *Lower = TestIsLessOp.getValue()
+                      ? tryBuildCapture(SemaRef, LB, Captures).get()
+                      : Cnt;
     if (!Upper || !Lower)
       return nullptr;
 
@@ -4686,6 +4691,9 @@ Expr *OpenMPIterationSpaceChecker::buildOrderedLoopData(
 
 /// Iteration space of a single for loop.
 struct LoopIterationSpace final {
+  /// True if the condition operator is the strict compare operator (<, > or
+  /// !=).
+  bool IsStrictCompare = false;
   /// Condition of the loop.
   Expr *PreCond = nullptr;
   /// This expression calculates the number of iterations in the loop.
@@ -4892,6 +4900,7 @@ static bool checkOpenMPIterationSpace(
   ResultIterSpace.CondSrcRange = ISC.getConditionSrcRange();
   ResultIterSpace.IncSrcRange = ISC.getIncrementSrcRange();
   ResultIterSpace.Subtract = ISC.shouldSubtractStep();
+  ResultIterSpace.IsStrictCompare = ISC.isStrictTestOp();
 
   HasErrors |= (ResultIterSpace.PreCond == nullptr ||
                 ResultIterSpace.NumIterations == nullptr ||
@@ -5139,8 +5148,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   // This is helper routine for loop directives (e.g., 'for', 'simd',
   // 'for simd', etc.).
   llvm::MapVector<const Expr *, DeclRefExpr *> Captures;
-  SmallVector<LoopIterationSpace, 4> IterSpaces;
-  IterSpaces.resize(std::max(OrderedLoopCount, NestedLoopCount));
+  SmallVector<LoopIterationSpace, 4> IterSpaces(
+      std::max(OrderedLoopCount, NestedLoopCount));
   Stmt *CurStmt = AStmt->IgnoreContainers(/* IgnoreCaptured */ true);
   for (unsigned Cnt = 0; Cnt < NestedLoopCount; ++Cnt) {
     if (checkOpenMPIterationSpace(
@@ -5446,25 +5455,55 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
     }
   }
 
-  // Loop condition (IV < NumIterations) or (IV <= UB) for worksharing loops.
+  bool UseStrictCompare =
+      RealVType->hasUnsignedIntegerRepresentation() &&
+      llvm::all_of(IterSpaces, [](const LoopIterationSpace &LIS) {
+        return LIS.IsStrictCompare;
+      });
+  // Loop condition (IV < NumIterations) or (IV <= UB or IV < UB + 1 (for
+  // unsigned IV)) for worksharing loops.
   SourceLocation CondLoc = AStmt->getBeginLoc();
+  Expr *BoundUB = UB.get();
+  if (UseStrictCompare) {
+    BoundUB =
+        SemaRef
+            .BuildBinOp(CurScope, CondLoc, BO_Add, BoundUB,
+                        SemaRef.ActOnIntegerConstant(SourceLocation(), 1).get())
+            .get();
+    BoundUB =
+        SemaRef.ActOnFinishFullExpr(BoundUB, /*DiscardedValue*/ false).get();
+  }
   ExprResult Cond =
       (isOpenMPWorksharingDirective(DKind) ||
        isOpenMPTaskLoopDirective(DKind) || isOpenMPDistributeDirective(DKind))
-          ? SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), UB.get())
+          ? SemaRef.BuildBinOp(CurScope, CondLoc,
+                               UseStrictCompare ? BO_LT : BO_LE, IV.get(),
+                               BoundUB)
           : SemaRef.BuildBinOp(CurScope, CondLoc, BO_LT, IV.get(),
                                NumIterations.get());
   ExprResult CombDistCond;
   if (isOpenMPLoopBoundSharingDirective(DKind)) {
-    CombDistCond =
-        SemaRef.BuildBinOp(
-            CurScope, CondLoc, BO_LT, IV.get(), NumIterations.get());
+    CombDistCond = SemaRef.BuildBinOp(CurScope, CondLoc, BO_LT, IV.get(),
+                                      NumIterations.get());
   }
 
   ExprResult CombCond;
   if (isOpenMPLoopBoundSharingDirective(DKind)) {
+    Expr *BoundCombUB = CombUB.get();
+    if (UseStrictCompare) {
+      BoundCombUB =
+          SemaRef
+              .BuildBinOp(
+                  CurScope, CondLoc, BO_Add, BoundCombUB,
+                  SemaRef.ActOnIntegerConstant(SourceLocation(), 1).get())
+              .get();
+      BoundCombUB =
+          SemaRef.ActOnFinishFullExpr(BoundCombUB, /*DiscardedValue*/ false)
+              .get();
+    }
     CombCond =
-        SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), CombUB.get());
+        SemaRef.BuildBinOp(CurScope, CondLoc, UseStrictCompare ? BO_LT : BO_LE,
+                           IV.get(), BoundCombUB);
   }
   // Loop increment (IV = IV + 1)
   SourceLocation IncLoc = AStmt->getBeginLoc();
@@ -5541,7 +5580,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   SourceLocation DistIncLoc = AStmt->getBeginLoc();
   ExprResult DistCond, DistInc, PrevEUB, ParForInDistCond;
   if (isOpenMPLoopBoundSharingDirective(DKind)) {
-    DistCond = SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), UB.get());
+    DistCond = SemaRef.BuildBinOp(
+        CurScope, CondLoc, UseStrictCompare ? BO_LT : BO_LE, IV.get(), BoundUB);
     assert(DistCond.isUsable() && "distribute cond expr was not built");
 
     DistInc =
@@ -5565,10 +5605,24 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
     PrevEUB =
         SemaRef.ActOnFinishFullExpr(PrevEUB.get(), /*DiscardedValue*/ false);
 
-    // Build IV <= PrevUB to be used in parallel for is in combination with
-    // a distribute directive with schedule(static, 1)
+    // Build IV <= PrevUB or IV < PrevUB + 1 for unsigned IV to be used in
+    // parallel for is in combination with a distribute directive with
+    // schedule(static, 1)
+    Expr *BoundPrevUB = PrevUB.get();
+    if (UseStrictCompare) {
+      BoundPrevUB =
+          SemaRef
+              .BuildBinOp(
+                  CurScope, CondLoc, BO_Add, BoundPrevUB,
+                  SemaRef.ActOnIntegerConstant(SourceLocation(), 1).get())
+              .get();
+      BoundPrevUB =
+          SemaRef.ActOnFinishFullExpr(BoundPrevUB, /*DiscardedValue*/ false)
+              .get();
+    }
     ParForInDistCond =
-        SemaRef.BuildBinOp(CurScope, CondLoc, BO_LE, IV.get(), PrevUB.get());
+        SemaRef.BuildBinOp(CurScope, CondLoc, UseStrictCompare ? BO_LT : BO_LE,
+                           IV.get(), BoundPrevUB);
   }
 
   // Build updates and final values of the loop counters.

diff --git a/clang/test/OpenMP/for_codegen.cpp b/clang/test/OpenMP/for_codegen.cpp
index 2e44478b632f788f8a500779ec4079ceb8bc3084..47c5be9becfc416309e9be9372ca364117bd8134 100644 (file)
--- a/clang/test/OpenMP/for_codegen.cpp
+++ b/clang/test/OpenMP/for_codegen.cpp
@@ -203,7 +203,8 @@ void dynamic1(float *a, float *b, float *c, float *d) {
 // CHECK: [[IV:%.+]] = load i64, i64* [[OMP_IV]]
 
 // CHECK-NEXT: [[UB:%.+]] = load i64, i64* [[OMP_UB]]
-// CHECK-NEXT: [[CMP:%.+]] = icmp ule i64 [[IV]], [[UB]]
+// CHECK-NEXT: [[BOUND:%.+]] = add i64 [[UB]], 1
+// CHECK-NEXT: [[CMP:%.+]] = icmp ult i64 [[IV]], [[BOUND]]
 // CHECK-NEXT: br i1 [[CMP]], label %[[LOOP1_BODY:[^,]+]], label %[[LOOP1_END:[^,]+]]
   for (unsigned long long i = 131071; i < 2147483647; i += 127) {
 // CHECK: [[LOOP1_BODY]]
@@ -244,7 +245,8 @@ void guided7(float *a, float *b, float *c, float *d) {
 // CHECK: [[IV:%.+]] = load i64, i64* [[OMP_IV]]
 
 // CHECK-NEXT: [[UB:%.+]] = load i64, i64* [[OMP_UB]]
-// CHECK-NEXT: [[CMP:%.+]] = icmp ule i64 [[IV]], [[UB]]
+// CHECK-NEXT: [[BOUND:%.+]] = add i64 [[UB]], 1
+// CHECK-NEXT: [[CMP:%.+]] = icmp ult i64 [[IV]], [[BOUND]]
 // CHECK-NEXT: br i1 [[CMP]], label %[[LOOP1_BODY:[^,]+]], label %[[LOOP1_END:[^,]+]]
   for (unsigned long long i = 131071; i < 2147483647; i += 127) {
 // CHECK: [[LOOP1_BODY]]

diff --git a/clang/test/OpenMP/ordered_codegen.cpp b/clang/test/OpenMP/ordered_codegen.cpp
index ef7d39dfd0aa9222ea8d326a450a0e555f2f8339..70da820c1f7b637ffe26da7ba649cec805ccd01b 100644 (file)
--- a/clang/test/OpenMP/ordered_codegen.cpp
+++ b/clang/test/OpenMP/ordered_codegen.cpp
@@ -78,7 +78,8 @@ void dynamic1(float *a, float *b, float *c, float *d) {
 // CHECK: [[IV:%.+]] = load i64, i64* [[OMP_IV]]
 
 // CHECK-NEXT: [[UB:%.+]] = load i64, i64* [[OMP_UB]]
-// CHECK-NEXT: [[CMP:%.+]] = icmp ule i64 [[IV]], [[UB]]
+// CHECK-NEXT: [[BOUND:%.+]] = add i64 [[UB]], 1
+// CHECK-NEXT: [[CMP:%.+]] = icmp ult i64 [[IV]], [[BOUND]]
 // CHECK-NEXT: br i1 [[CMP]], label %[[LOOP1_BODY:[^,]+]], label %[[LOOP1_END:[^,]+]]
   for (unsigned long long i = 131071; i < 2147483647; i += 127) {
 // CHECK: [[LOOP1_BODY]]

diff --git a/clang/test/OpenMP/parallel_for_codegen.cpp b/clang/test/OpenMP/parallel_for_codegen.cpp
index a3d307afac974b51e57697448aaa9a829b73d37a..fe1eb1ef114de0dccfa8b278648d37ef405444d1 100644 (file)
--- a/clang/test/OpenMP/parallel_for_codegen.cpp
+++ b/clang/test/OpenMP/parallel_for_codegen.cpp
@@ -197,7 +197,8 @@ void dynamic1(float *a, float *b, float *c, float *d) {
 // CHECK: [[IV:%.+]] = load i64, i64* [[OMP_IV]]
 
 // CHECK-NEXT: [[UB:%.+]] = load i64, i64* [[OMP_UB]]
-// CHECK-NEXT: [[CMP:%.+]] = icmp ule i64 [[IV]], [[UB]]
+// CHECK-NEXT: [[BOUND:%.+]] = add i64 [[UB]], 1
+// CHECK-NEXT: [[CMP:%.+]] = icmp ult i64 [[IV]], [[BOUND]]
 // CHECK-NEXT: br i1 [[CMP]], label %[[LOOP1_BODY:[^,]+]], label %[[LOOP1_END:[^,]+]]
   for (unsigned long long i = 131071; i < 2147483647; i += 127) {
 // CHECK: [[LOOP1_BODY]]
@@ -239,7 +240,8 @@ void guided7(float *a, float *b, float *c, float *d) {
 // CHECK: [[IV:%.+]] = load i64, i64* [[OMP_IV]]
 
 // CHECK-NEXT: [[UB:%.+]] = load i64, i64* [[OMP_UB]]
-// CHECK-NEXT: [[CMP:%.+]] = icmp ule i64 [[IV]], [[UB]]
+// CHECK-NEXT: [[BOUND:%.+]] = add i64 [[UB]], 1
+// CHECK-NEXT: [[CMP:%.+]] = icmp ult i64 [[IV]], [[BOUND]]
 // CHECK-NEXT: br i1 [[CMP]], label %[[LOOP1_BODY:[^,]+]], label %[[LOOP1_END:[^,]+]]
   for (unsigned long long i = 131071; i < 2147483647; i += 127) {
 // CHECK: [[LOOP1_BODY]]