[PATCH] D99266: [SLP]Improve and simplify extendSchedulingRegion.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev created this revision.
ABataev added reviewers: RKSimon, spatel, dtemirbulatov, anton-afanasyev, lebedev.ri.
Herald added a subscriber: hiraditya.
ABataev requested review of this revision.
Herald added a project: LLVM.

We do not need to scan further if the upper end or lower end of the
basic block is reached already and the instruction is not found. It
means that the instruction is definitely in the lower part of basic
block or in the upper block relatively.
This should improve compile time for the very big basic blocks.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D99266

Files:
  llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  llvm/test/Transforms/SLPVectorizer/X86/crash_exceed_scheduling.ll


Index: llvm/test/Transforms/SLPVectorizer/X86/crash_exceed_scheduling.ll
===================================================================
--- llvm/test/Transforms/SLPVectorizer/X86/crash_exceed_scheduling.ll
+++ llvm/test/Transforms/SLPVectorizer/X86/crash_exceed_scheduling.ll
@@ -44,13 +44,9 @@
 ; CHECK:       bb1:
 ; CHECK-NEXT:    br label [[LABEL:%.*]]
 ; CHECK:       bb2:
-; CHECK-NEXT:    [[TMP17:%.*]] = extractelement <2 x double> [[TMP16]], i32 0
-; CHECK-NEXT:    [[TMP18:%.*]] = insertelement <2 x double> poison, double [[TMP17]], i32 0
-; CHECK-NEXT:    [[TMP19:%.*]] = extractelement <2 x double> [[TMP16]], i32 1
-; CHECK-NEXT:    [[TMP20:%.*]] = insertelement <2 x double> [[TMP18]], double [[TMP19]], i32 1
 ; CHECK-NEXT:    br label [[LABEL]]
 ; CHECK:       label:
-; CHECK-NEXT:    [[TMP21:%.*]] = phi <2 x double> [ [[TMP12]], [[BB1]] ], [ [[TMP20]], [[BB2]] ]
+; CHECK-NEXT:    [[TMP17:%.*]] = phi <2 x double> [ [[TMP12]], [[BB1]] ], [ [[TMP16]], [[BB2]] ]
 ; CHECK-NEXT:    ret void
 ;
 entry:
Index: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -5336,41 +5336,39 @@
   BasicBlock::reverse_iterator UpperEnd = BB->rend();
   BasicBlock::iterator DownIter = ScheduleEnd->getIterator();
   BasicBlock::iterator LowerEnd = BB->end();
-  while (true) {
+  while (UpIter != UpperEnd && DownIter != LowerEnd && &*UpIter != I &&
+         &*DownIter != I) {
     if (++ScheduleRegionSize > ScheduleRegionSizeLimit) {
       LLVM_DEBUG(dbgs() << "SLP:  exceeded schedule region size limit\n");
       return false;
     }
 
-    if (UpIter != UpperEnd) {
-      if (&*UpIter == I) {
-        initScheduleData(I, ScheduleStart, nullptr, FirstLoadStoreInRegion);
-        ScheduleStart = I;
-        if (isOneOf(S, I) != I)
-          CheckSheduleForI(I);
-        LLVM_DEBUG(dbgs() << "SLP:  extend schedule region start to " << *I
-                          << "\n");
-        return true;
-      }
-      ++UpIter;
-    }
-    if (DownIter != LowerEnd) {
-      if (&*DownIter == I) {
-        initScheduleData(ScheduleEnd, I->getNextNode(), LastLoadStoreInRegion,
-                         nullptr);
-        ScheduleEnd = I->getNextNode();
-        if (isOneOf(S, I) != I)
-          CheckSheduleForI(I);
-        assert(ScheduleEnd && "tried to vectorize a terminator?");
-        LLVM_DEBUG(dbgs() << "SLP:  extend schedule region end to " << *I
-                          << "\n");
-        return true;
-      }
-      ++DownIter;
-    }
-    assert((UpIter != UpperEnd || DownIter != LowerEnd) &&
-           "instruction not found in block");
+    ++UpIter;
+    ++DownIter;
+  }
+  if (DownIter == LowerEnd || (UpIter != UpperEnd && &*UpIter == I)) {
+    assert(I->getParent() == ScheduleStart->getParent() &&
+           "Instruction is in wrong basic block.");
+    initScheduleData(I, ScheduleStart, nullptr, FirstLoadStoreInRegion);
+    ScheduleStart = I;
+    if (isOneOf(S, I) != I)
+      CheckSheduleForI(I);
+    LLVM_DEBUG(dbgs() << "SLP:  extend schedule region start to " << *I
+                      << "\n");
+    return true;
   }
+  assert((UpIter == UpperEnd || (DownIter != LowerEnd && &*DownIter == I)) &&
+         "Expected to reach top of the basic block or instruction down the "
+         "lower end.");
+  assert(I->getParent() == ScheduleEnd->getParent() &&
+         "Instruction is in wrong basic block.");
+  initScheduleData(ScheduleEnd, I->getNextNode(), LastLoadStoreInRegion,
+                   nullptr);
+  ScheduleEnd = I->getNextNode();
+  if (isOneOf(S, I) != I)
+    CheckSheduleForI(I);
+  assert(ScheduleEnd && "tried to vectorize a terminator?");
+  LLVM_DEBUG(dbgs() << "SLP:  extend schedule region end to " << *I << "\n");
   return true;
 }
 


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