[llvm] r213772 - In unroll pragma syntax and loop hint metadata, change "enable" forms to a new form using the string "full".

Mark Heffernan meheff at google.com
Wed Jul 23 10:31:37 PDT 2014


Author: meheff
Date: Wed Jul 23 12:31:37 2014
New Revision: 213772

URL: http://llvm.org/viewvc/llvm-project?rev=213772&view=rev
Log:
In unroll pragma syntax and loop hint metadata, change "enable" forms to a new form using the string "full".

Modified:
    llvm/trunk/docs/LangRef.rst
    llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp
    llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
    llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll

Modified: llvm/trunk/docs/LangRef.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.rst?rev=213772&r1=213771&r2=213772&view=diff
==============================================================================
--- llvm/trunk/docs/LangRef.rst (original)
+++ llvm/trunk/docs/LangRef.rst Wed Jul 23 12:31:37 2014
@@ -2987,20 +2987,6 @@ identification metadata. The ``llvm.loop
 optimization hints and the unrolling will only be performed if the
 optimizer believes it is safe to do so.
 
-'``llvm.loop.unroll.enable``' Metadata
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-This metadata either disables loop unrolling or suggests that the loop
-be unrolled fully. The first operand is the string
-``llvm.loop.unroll.enable`` and the second operand is a bit.  If the
-bit operand value is 0 loop unrolling is disabled. A value of 1
-indicates that the loop should be fully unrolled. For example:
-
-.. code-block:: llvm
-
-   !0 = metadata !{ metadata !"llvm.loop.unroll.enable", i1 0 }
-   !1 = metadata !{ metadata !"llvm.loop.unroll.enable", i1 1 }
-
 '``llvm.loop.unroll.count``' Metadata
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
@@ -3016,12 +3002,26 @@ example:
 If the trip count of the loop is less than the unroll count the loop
 will be partially unrolled.
 
-If a loop has both a ``llvm.loop.unroll.enable`` metadata and
-``llvm.loop.unroll.count`` metadata the behavior depends upon the
-value of the ``llvm.loop.unroll.enable`` operand.  If the value is 0,
-the loop will not be unrolled.  If the value is 1, the loop will be
-unrolled with a factor determined by the ``llvm.loop.unroll.count``
-operand effectively ignoring the ``llvm.loop.unroll.enable`` metadata.
+'``llvm.loop.unroll.disable``' Metadata
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This metadata either disables loop unrolling. The metadata has a single operand
+which is the string ``llvm.loop.unroll.disable``.  For example:
+
+.. code-block:: llvm
+
+   !0 = metadata !{ metadata !"llvm.loop.unroll.disable" }
+
+'``llvm.loop.unroll.full``' Metadata
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This metadata either suggests that the loop should be unrolled fully. The
+metadata has a single operand which is the string ``llvm.loop.unroll.disable``.
+For example:
+
+.. code-block:: llvm
+
+   !0 = metadata !{ metadata !"llvm.loop.unroll.full" }
 
 '``llvm.mem``'
 ^^^^^^^^^^^^^^^

Modified: llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp?rev=213772&r1=213771&r2=213772&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopUnrollPass.cpp Wed Jul 23 12:31:37 2014
@@ -52,7 +52,7 @@ UnrollRuntime("unroll-runtime", cl::Zero
 
 static cl::opt<unsigned>
 PragmaUnrollThreshold("pragma-unroll-threshold", cl::init(16 * 1024), cl::Hidden,
-  cl::desc("Unrolled size limit for loops with an unroll(enable) or "
+  cl::desc("Unrolled size limit for loops with an unroll(full) or "
            "unroll_count pragma."));
 
 namespace {
@@ -138,12 +138,11 @@ namespace {
     // SetExplicitly is set to true if the unroll count is is set by
     // the user or a pragma rather than selected heuristically.
     unsigned
-    selectUnrollCount(const Loop *L, unsigned TripCount, bool HasEnablePragma,
+    selectUnrollCount(const Loop *L, unsigned TripCount, bool PragmaFullUnroll,
                       unsigned PragmaCount,
                       const TargetTransformInfo::UnrollingPreferences &UP,
                       bool &SetExplicitly);
 
-
     // Select threshold values used to limit unrolling based on a
     // total unrolled size.  Parameters Threshold and PartialThreshold
     // are set to the maximum unrolled size for fully and partially
@@ -219,13 +218,13 @@ static unsigned ApproximateLoopSize(cons
   return LoopSize;
 }
 
-// Returns the value associated with the given metadata node name (for
-// example, "llvm.loop.unroll.count").  If no such named metadata node
-// exists, then nullptr is returned.
-static const ConstantInt *GetUnrollMetadataValue(const Loop *L,
-                                                 StringRef Name) {
+// Returns the loop hint metadata node with the given name (for example,
+// "llvm.loop.unroll.count").  If no such metadata node exists, then nullptr is
+// returned.
+const MDNode *GetUnrollMetadata(const Loop *L, StringRef Name) {
   MDNode *LoopID = L->getLoopID();
-  if (!LoopID) return nullptr;
+  if (!LoopID)
+    return nullptr;
 
   // First operand should refer to the loop id itself.
   assert(LoopID->getNumOperands() > 0 && "requires at least one operand");
@@ -233,41 +232,37 @@ static const ConstantInt *GetUnrollMetad
 
   for (unsigned i = 1, e = LoopID->getNumOperands(); i < e; ++i) {
     const MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
-    if (!MD) continue;
+    if (!MD)
+      continue;
 
     const MDString *S = dyn_cast<MDString>(MD->getOperand(0));
-    if (!S) continue;
+    if (!S)
+      continue;
 
-    if (Name.equals(S->getString())) {
-      assert(MD->getNumOperands() == 2 &&
-             "Unroll hint metadata should have two operands.");
-      return cast<ConstantInt>(MD->getOperand(1));
-    }
+    if (Name.equals(S->getString()))
+      return MD;
   }
   return nullptr;
 }
 
-// Returns true if the loop has an unroll(enable) pragma.
-static bool HasUnrollEnablePragma(const Loop *L) {
-  const ConstantInt *EnableValue =
-      GetUnrollMetadataValue(L, "llvm.loop.unroll.enable");
-  return (EnableValue && EnableValue->getZExtValue());
+// Returns true if the loop has an unroll(full) pragma.
+static bool HasUnrollFullPragma(const Loop *L) {
+  return GetUnrollMetadata(L, "llvm.loop.unroll.full");
 }
 
 // Returns true if the loop has an unroll(disable) pragma.
 static bool HasUnrollDisablePragma(const Loop *L) {
-  const ConstantInt *EnableValue =
-      GetUnrollMetadataValue(L, "llvm.loop.unroll.enable");
-  return (EnableValue && !EnableValue->getZExtValue());
+  return GetUnrollMetadata(L, "llvm.loop.unroll.disable");
 }
 
 // If loop has an unroll_count pragma return the (necessarily
 // positive) value from the pragma.  Otherwise return 0.
 static unsigned UnrollCountPragmaValue(const Loop *L) {
-  const ConstantInt *CountValue =
-      GetUnrollMetadataValue(L, "llvm.loop.unroll.count");
-  if (CountValue) {
-    unsigned Count = CountValue->getZExtValue();
+  const MDNode *MD = GetUnrollMetadata(L, "llvm.loop.unroll.count");
+  if (MD) {
+    assert(MD->getNumOperands() == 2 &&
+           "Unroll count hint metadata should have two operands.");
+    unsigned Count = cast<ConstantInt>(MD->getOperand(1))->getZExtValue();
     assert(Count >= 1 && "Unroll count must be positive.");
     return Count;
   }
@@ -298,9 +293,8 @@ static void SetLoopAlreadyUnrolled(Loop
 
   // Add unroll(disable) metadata to disable future unrolling.
   LLVMContext &Context = L->getHeader()->getContext();
-  SmallVector<Value *, 2> DisableOperands;
-  DisableOperands.push_back(MDString::get(Context, "llvm.loop.unroll.enable"));
-  DisableOperands.push_back(ConstantInt::get(Type::getInt1Ty(Context), 0));
+  SmallVector<Value *, 1> DisableOperands;
+  DisableOperands.push_back(MDString::get(Context, "llvm.loop.unroll.disable"));
   MDNode *DisableNode = MDNode::get(Context, DisableOperands);
   Vals.push_back(DisableNode);
 
@@ -312,7 +306,7 @@ static void SetLoopAlreadyUnrolled(Loop
 }
 
 unsigned LoopUnroll::selectUnrollCount(
-    const Loop *L, unsigned TripCount, bool HasEnablePragma,
+    const Loop *L, unsigned TripCount, bool PragmaFullUnroll,
     unsigned PragmaCount, const TargetTransformInfo::UnrollingPreferences &UP,
     bool &SetExplicitly) {
   SetExplicitly = true;
@@ -326,9 +320,7 @@ unsigned LoopUnroll::selectUnrollCount(
   if (Count == 0) {
     if (PragmaCount) {
       Count = PragmaCount;
-    } else if (HasEnablePragma) {
-      // unroll(enable) pragma without an unroll_count pragma
-      // indicates to unroll loop fully.
+    } else if (PragmaFullUnroll) {
       Count = TripCount;
     }
   }
@@ -368,9 +360,9 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPa
   if (HasUnrollDisablePragma(L)) {
     return false;
   }
-  bool HasEnablePragma = HasUnrollEnablePragma(L);
+  bool PragmaFullUnroll = HasUnrollFullPragma(L);
   unsigned PragmaCount = UnrollCountPragmaValue(L);
-  bool HasPragma = HasEnablePragma || PragmaCount > 0;
+  bool HasPragma = PragmaFullUnroll || PragmaCount > 0;
 
   TargetTransformInfo::UnrollingPreferences UP;
   getUnrollingPreferences(L, TTI, UP);
@@ -390,8 +382,8 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPa
   // Select an initial unroll count.  This may be reduced later based
   // on size thresholds.
   bool CountSetExplicitly;
-  unsigned Count = selectUnrollCount(L, TripCount, HasEnablePragma, PragmaCount,
-                                     UP, CountSetExplicitly);
+  unsigned Count = selectUnrollCount(L, TripCount, PragmaFullUnroll,
+                                     PragmaCount, UP, CountSetExplicitly);
 
   unsigned NumInlineCandidates;
   bool notDuplicatable;
@@ -474,16 +466,16 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPa
     DebugLoc LoopLoc = L->getStartLoc();
     Function *F = Header->getParent();
     LLVMContext &Ctx = F->getContext();
-    if (HasEnablePragma && PragmaCount == 0) {
+    if (PragmaFullUnroll && PragmaCount == 0) {
       if (TripCount && Count != TripCount) {
         emitOptimizationRemarkMissed(
             Ctx, DEBUG_TYPE, *F, LoopLoc,
-            "Unable to fully unroll loop as directed by unroll(enable) pragma "
+            "Unable to fully unroll loop as directed by unroll(full) pragma "
             "because unrolled size is too large.");
       } else if (!TripCount) {
         emitOptimizationRemarkMissed(
             Ctx, DEBUG_TYPE, *F, LoopLoc,
-            "Unable to fully unroll loop as directed by unroll(enable) pragma "
+            "Unable to fully unroll loop as directed by unroll(full) pragma "
             "because loop has a runtime trip count.");
       }
     } else if (PragmaCount > 0 && Count != OriginalCount) {

Modified: llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll?rev=213772&r1=213771&r2=213772&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll (original)
+++ llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll Wed Jul 23 12:31:37 2014
@@ -6,9 +6,9 @@
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
-; #pragma clang loop  vectorize(enable) unroll(enable) unroll_count(4) vectorize_width(8)
+; #pragma clang loop  vectorize(enable) unroll(full) unroll_count(4) vectorize_width(8)
 ;
-; Unroll metadata should be replaces with unroll(disable).  Vectorize
+; Unroll metadata should be replaced with unroll(disable).  Vectorize
 ; metadata should be untouched.
 ;
 ; CHECK-LABEL: @loop1(
@@ -32,7 +32,7 @@ for.end:
 }
 !1 = metadata !{metadata !1, metadata !2, metadata !3, metadata !4, metadata !5}
 !2 = metadata !{metadata !"llvm.loop.vectorize.enable", i1 true}
-!3 = metadata !{metadata !"llvm.loop.unroll.enable", i1 true}
+!3 = metadata !{metadata !"llvm.loop.unroll.full"}
 !4 = metadata !{metadata !"llvm.loop.unroll.count", i32 4}
 !5 = metadata !{metadata !"llvm.loop.vectorize.width", i32 8}
 
@@ -60,10 +60,10 @@ for.end:
   ret void
 }
 !6 = metadata !{metadata !6, metadata !7}
-!7 = metadata !{metadata !"llvm.loop.unroll.enable", i1 false}
+!7 = metadata !{metadata !"llvm.loop.unroll.disable"}
 
 ; CHECK: ![[LOOP_1]] = metadata !{metadata ![[LOOP_1]], metadata ![[VEC_ENABLE:.*]], metadata ![[WIDTH_8:.*]], metadata ![[UNROLL_DISABLE:.*]]}
 ; CHECK: ![[VEC_ENABLE]] = metadata !{metadata !"llvm.loop.vectorize.enable", i1 true}
 ; CHECK: ![[WIDTH_8]] = metadata !{metadata !"llvm.loop.vectorize.width", i32 8}
-; CHECK: ![[UNROLL_DISABLE]] = metadata !{metadata !"llvm.loop.unroll.enable", i1 false}
+; CHECK: ![[UNROLL_DISABLE]] = metadata !{metadata !"llvm.loop.unroll.disable"}
 ; CHECK: ![[LOOP_2]] = metadata !{metadata ![[LOOP_2]], metadata ![[UNROLL_DISABLE:.*]]}

Modified: llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll?rev=213772&r1=213771&r2=213772&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll (original)
+++ llvm/trunk/test/Transforms/LoopUnroll/unroll-pragmas.ll Wed Jul 23 12:31:37 2014
@@ -55,11 +55,11 @@ for.end:
   ret void
 }
 !1 = metadata !{metadata !1, metadata !2}
-!2 = metadata !{metadata !"llvm.loop.unroll.enable", i1 false}
+!2 = metadata !{metadata !"llvm.loop.unroll.disable"}
 
 ; loop64 has a high enough count that it should *not* be unrolled by
 ; the default unrolling heuristic.  It serves as the control for the
-; unroll(enable) pragma test loop64_with_.* tests below.
+; unroll(full) pragma test loop64_with_.* tests below.
 ;
 ; CHECK-LABEL: @loop64(
 ; CHECK: store i32
@@ -83,7 +83,7 @@ for.end:
   ret void
 }
 
-; #pragma clang loop unroll(enable)
+; #pragma clang loop unroll(full)
 ; Loop should be fully unrolled.
 ;
 ; CHECK-LABEL: @loop64_with_enable(
@@ -106,7 +106,7 @@ for.end:
   ret void
 }
 !3 = metadata !{metadata !3, metadata !4}
-!4 = metadata !{metadata !"llvm.loop.unroll.enable", i1 true}
+!4 = metadata !{metadata !"llvm.loop.unroll.full"}
 
 ; #pragma clang loop unroll_count(4)
 ; Loop should be unrolled 4 times.
@@ -138,37 +138,7 @@ for.end:
 !5 = metadata !{metadata !5, metadata !6}
 !6 = metadata !{metadata !"llvm.loop.unroll.count", i32 4}
 
-
-; #pragma clang loop unroll_count(enable) unroll_count(4)
-; Loop should be unrolled 4 times.
-;
-; CHECK-LABEL: @loop64_with_enable_and_count4(
-; CHECK: store i32
-; CHECK: store i32
-; CHECK: store i32
-; CHECK: store i32
-; CHECK-NOT: store i32
-; CHECK: br i1
-define void @loop64_with_enable_and_count4(i32* nocapture %a) {
-entry:
-  br label %for.body
-
-for.body:                                         ; preds = %for.body, %entry
-  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
-  %arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv
-  %0 = load i32* %arrayidx, align 4
-  %inc = add nsw i32 %0, 1
-  store i32 %inc, i32* %arrayidx, align 4
-  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
-  %exitcond = icmp eq i64 %indvars.iv.next, 64
-  br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !7
-
-for.end:                                          ; preds = %for.body
-  ret void
-}
-!7 = metadata !{metadata !7, metadata !6, metadata !4}
-
-; #pragma clang loop unroll_count(enable)
+; #pragma clang loop unroll(full)
 ; Full unrolling is requested, but loop has a dynamic trip count so
 ; no unrolling should occur.
 ;
@@ -261,7 +231,7 @@ for.end:
 !10 = metadata !{metadata !10, metadata !11}
 !11 = metadata !{metadata !"llvm.loop.unroll.count", i32 1}
 
-; #pragma clang loop unroll(enable)
+; #pragma clang loop unroll(full)
 ; Loop has very high loop count (1 million) and full unrolling was requested.
 ; Loop should unrolled up to the pragma threshold, but not completely.
 ;





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