[PATCH] D90055: [ARM] Don't aggressively unroll vector remainder loops

[Dave Green via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGc7e275388e3f: [ARM] Don't aggressively unroll vector remainder loops (authored by dmgreen).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D90055/new/

https://reviews.llvm.org/D90055

Files:
  llvm/include/llvm/Transforms/Utils/LoopUtils.h
  llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
  llvm/lib/Transforms/Utils/LoopUtils.cpp
  llvm/test/Transforms/LoopUnroll/ARM/mve-nounroll.ll


Index: llvm/test/Transforms/LoopUnroll/ARM/mve-nounroll.ll
===================================================================
--- llvm/test/Transforms/LoopUnroll/ARM/mve-nounroll.ll
+++ llvm/test/Transforms/LoopUnroll/ARM/mve-nounroll.ll
@@ -70,15 +70,11 @@
 
 ; CHECK-LABEL: @remainder
 ; CHECK: vector.body:
-; CHECK:   br i1 %13, label %middle.block, label %vector.body, !llvm.loop !0
+; CHECK:   br i1 %7, label %middle.block, label %vector.body, !llvm.loop !0
 ; CHECK: middle.block:
 ; CHECK:   br i1 %cmp.n, label %for.cond.cleanup, label %for.body.preheader13
 ; CHECK: for.body:
-; CHECK:   br i1 %exitcond.3, label %for.cond.cleanup.loopexit.unr-lcssa, label %for.body, !llvm.loop !0
-; CHECK: for.body.prol.1:
-; CHECK:   br i1 %prol.iter.cmp.1, label %for.body.prol.2, label %for.body.prol.loopexit.unr-lcssa
-; CHECK: for.body.prol.2:
-; CHECK:   br label %for.body.prol.loopexit.unr-lcssa
+; CHECK:   br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body, !llvm.loop !0
 
 define void @remainder(float* %s1, float* %s2, float* %d, i32 %n) {
 entry:
Index: llvm/lib/Transforms/Utils/LoopUtils.cpp
===================================================================
--- llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -297,7 +297,7 @@
   llvm_unreachable("unexpected number of options");
 }
 
-static bool getBooleanLoopAttribute(const Loop *TheLoop, StringRef Name) {
+bool llvm::getBooleanLoopAttribute(const Loop *TheLoop, StringRef Name) {
   return getOptionalBoolLoopAttribute(TheLoop, Name).getValueOr(false);
 }
 
Index: llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
===================================================================
--- llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
+++ llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
@@ -1946,6 +1946,10 @@
   if (ST->hasBranchPredictor() && L->getNumBlocks() > 4)
     return;
 
+  // Don't unroll vectorized loops, including the remainder loop
+  if (getBooleanLoopAttribute(L, "llvm.loop.isvectorized"))
+    return;
+
   // Scan the loop: don't unroll loops with calls as this could prevent
   // inlining.
   unsigned Cost = 0;
Index: llvm/include/llvm/Transforms/Utils/LoopUtils.h
===================================================================
--- llvm/include/llvm/Transforms/Utils/LoopUtils.h
+++ llvm/include/llvm/Transforms/Utils/LoopUtils.h
@@ -271,6 +271,9 @@
 void addStringMetadataToLoop(Loop *TheLoop, const char *MDString,
                              unsigned V = 0);
 
+/// Returns true if Name is applied to TheLoop and enabled.
+bool getBooleanLoopAttribute(const Loop *TheLoop, StringRef Name);
+
 /// Returns a loop's estimated trip count based on branch weight metadata.
 /// In addition if \p EstimatedLoopInvocationWeight is not null it is
 /// initialized with weight of loop's latch leading to the exit.


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