[llvm] c96c85a - Revert "[LoopSink] Allow sinking to PHI-use"

Alexander Kornienko via llvm-commits llvm-commits at lists.llvm.org
Wed Jun 21 08:37:23 PDT 2023


Author: Alexander Kornienko
Date: 2023-06-21T17:37:11+02:00
New Revision: c96c85aba28089ec840a867e289782831e9637ee

URL: https://github.com/llvm/llvm-project/commit/c96c85aba28089ec840a867e289782831e9637ee
DIFF: https://github.com/llvm/llvm-project/commit/c96c85aba28089ec840a867e289782831e9637ee.diff

LOG: Revert "[LoopSink] Allow sinking to PHI-use"

This reverts commit 54711a6a5872d5f97da4c0a1bd7e58d0546ca701.

The commit is causing a clang crash: https://reviews.llvm.org/D152772#4437254

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/LoopSink.cpp

Removed: 
    llvm/test/Transforms/LICM/loopsink-phi.ll


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/LoopSink.cpp b/llvm/lib/Transforms/Scalar/LoopSink.cpp
index 1d827b06faafa..7eeb1e7efb7e8 100644
--- a/llvm/lib/Transforms/Scalar/LoopSink.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopSink.cpp
@@ -177,27 +177,13 @@ static bool sinkInstruction(
   SmallPtrSet<BasicBlock *, 2> BBs;
   for (auto &U : I.uses()) {
     Instruction *UI = cast<Instruction>(U.getUser());
-
+    // We cannot sink I to PHI-uses.
+    if (isa<PHINode>(UI))
+      return false;
     // We cannot sink I if it has uses outside of the loop.
     if (!L.contains(LI.getLoopFor(UI->getParent())))
       return false;
-
-    if (!isa<PHINode>(UI)) {
-      BBs.insert(UI->getParent());
-      continue;
-    }
-
-    // We cannot sink I to PHI-uses, try to look through PHI to find the incoming
-    // block of the value being used.
-    PHINode *PN = dyn_cast<PHINode>(UI);
-    BasicBlock *PhiBB = PN->getIncomingBlock(U);
-
-    // If value's incoming block is from loop preheader directly, there's no
-    // place to sink to, bailout.
-    if (L.getLoopPreheader() == PhiBB)
-      return false;
-
-    BBs.insert(PhiBB);
+    BBs.insert(UI->getParent());
   }
 
   // findBBsToSinkInto is O(BBs.size() * ColdLoopBBs.size()). We cap the max

diff  --git a/llvm/test/Transforms/LICM/loopsink-phi.ll b/llvm/test/Transforms/LICM/loopsink-phi.ll
deleted file mode 100644
index 3a3fd31229400..0000000000000
--- a/llvm/test/Transforms/LICM/loopsink-phi.ll
+++ /dev/null
@@ -1,115 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
-; RUN: opt -S -verify-memoryssa -passes=loop-sink < %s | FileCheck %s
-; Make sure that unprofitable loop ICM can be undone by loop sink, and loop sink can handle
-; sinking through PHI use.
-
-
-define dso_local i32 @_Z3fooii(i32 %arg, i32 %arg1, i32 %arg2) local_unnamed_addr #0 !prof !29 {
-; CHECK-LABEL: define dso_local i32 @_Z3fooii
-; CHECK-SAME: (i32 [[ARG:%.*]], i32 [[ARG1:%.*]], i32 [[ARG2:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] !prof [[PROF29:![0-9]+]] {
-; CHECK-NEXT:  .l.check.preheader:
-; CHECK-NEXT:    br label [[DOTL_CHECK:%.*]]
-; CHECK:       .l.ret.loopexit:
-; CHECK-NEXT:    [[DOTLCSSA:%.*]] = phi i32 [ [[I10:%.*]], [[DOTL_ITERATE:%.*]] ]
-; CHECK-NEXT:    ret i32 [[DOTLCSSA]]
-; CHECK:       .l.check:
-; CHECK-NEXT:    [[I4:%.*]] = phi i32 [ 0, [[DOTL_CHECK_PREHEADER:%.*]] ], [ [[I11:%.*]], [[DOTL_ITERATE]] ]
-; CHECK-NEXT:    [[I5:%.*]] = phi i32 [ [[ARG]], [[DOTL_CHECK_PREHEADER]] ], [ [[I10]], [[DOTL_ITERATE]] ]
-; CHECK-NEXT:    [[I6:%.*]] = icmp eq i32 [[I4]], [[ARG1]]
-; CHECK-NEXT:    br i1 [[I6]], label [[DOTL_COLD:%.*]], label [[DOTL_ITERATE]], !prof [[PROF30:![0-9]+]]
-; CHECK:       .l.cold:
-; CHECK-NEXT:    [[FLAG:%.*]] = icmp eq i32 [[ARG1]], 5
-; CHECK-NEXT:    br i1 [[FLAG]], label [[DOTL_COLD1:%.*]], label [[DOTL_COLD2:%.*]]
-; CHECK:       .l.cold1:
-; CHECK-NEXT:    [[TMP1:%.*]] = mul nsw i32 [[ARG2]], [[ARG2]]
-; CHECK-NEXT:    br label [[DOTL_COLD3:%.*]]
-; CHECK:       .l.cold2:
-; CHECK-NEXT:    [[TMP2:%.*]] = add nsw i32 [[ARG2]], [[ARG2]]
-; CHECK-NEXT:    br label [[DOTL_COLD3]]
-; CHECK:       .l.cold3:
-; CHECK-NEXT:    [[I7:%.*]] = phi i32 [ [[TMP1]], [[DOTL_COLD1]] ], [ [[TMP2]], [[DOTL_COLD2]] ]
-; CHECK-NEXT:    [[I8:%.*]] = tail call i32 @_Z3bari(i32 [[I5]])
-; CHECK-NEXT:    [[I9:%.*]] = add nsw i32 [[I8]], [[I7]]
-; CHECK-NEXT:    br label [[DOTL_ITERATE]]
-; CHECK:       .l.iterate:
-; CHECK-NEXT:    [[I10]] = phi i32 [ [[I9]], [[DOTL_COLD3]] ], [ [[I5]], [[DOTL_CHECK]] ]
-; CHECK-NEXT:    [[I11]] = add nuw nsw i32 [[I4]], 1
-; CHECK-NEXT:    [[I12:%.*]] = icmp eq i32 [[I11]], [[I10]]
-; CHECK-NEXT:    br i1 [[I12]], label [[DOTL_RET_LOOPEXIT:%.*]], label [[DOTL_CHECK]]
-;
-
-.l.check.preheader:
-  %flag = icmp eq i32 %arg1, 5
-  %tmp2 = add nsw i32 %arg2, %arg2
-  %tmp1 = mul nsw i32 %arg2, %arg2
-  br label %.l.check
-
-.l.ret.loopexit:                                  ; preds = %.l.iterate
-  %.lcssa = phi i32 [ %i10, %.l.iterate ]
-  ret i32 %.lcssa
-
-.l.check:                                         ; preds = %.l.iterate, %.l.check.preheader
-  %i4 = phi i32 [ 0, %.l.check.preheader ], [ %i11, %.l.iterate ]
-  %i5 = phi i32 [ %arg, %.l.check.preheader ], [ %i10, %.l.iterate ]
-  %i6 = icmp eq i32 %i4, %arg1
-  br i1 %i6, label %.l.cold, label %.l.iterate, !prof !30
-
-.l.cold:                                          ; preds = %.l.check
-  br i1 %flag, label %.l.cold1, label %.l.cold2
-
-.l.cold1:                                         ; preds = %.l.cold
-  br label %.l.cold3
-
-.l.cold2:                                         ; preds = %.l.cold
-  br label %.l.cold3
-
-.l.cold3:                                         ; preds = %.l.cold2, %.l.cold1
-  %i7 = phi i32 [ %tmp1, %.l.cold1 ], [ %tmp2, %.l.cold2 ]
-  %i8 = tail call i32 @_Z3bari(i32 %i5)
-  %i9 = add nsw i32 %i8, %i7
-  br label %.l.iterate
-
-.l.iterate:                                       ; preds = %.l.cold3, %.l.check
-  %i10 = phi i32 [ %i9, %.l.cold3 ], [ %i5, %.l.check ]
-  %i11 = add nuw nsw i32 %i4, 1
-  %i12 = icmp eq i32 %i11, %i10
-  br i1 %i12, label %.l.ret.loopexit, label %.l.check
-}
-
-declare dso_local i32 @_Z3bari(i32) local_unnamed_addr
-
-attributes #0 = { "use-sample-profile" }
-
-!llvm.module.flags = !{!0}
-
-!0 = !{i32 1, !"ProfileSummary", !1}
-!1 = !{!2, !3, !4, !5, !6, !7, !8, !9, !10, !11}
-!2 = !{!"ProfileFormat", !"SampleProfile"}
-!3 = !{!"TotalCount", i64 403}
-!4 = !{!"MaxCount", i64 200}
-!5 = !{!"MaxInternalCount", i64 0}
-!6 = !{!"MaxFunctionCount", i64 1}
-!7 = !{!"NumCounts", i64 6}
-!8 = !{!"NumFunctions", i64 1}
-!9 = !{!"IsPartialProfile", i64 0}
-!10 = !{!"PartialProfileRatio", double 0.000000e+00}
-!11 = !{!"DetailedSummary", !12}
-!12 = !{!13, !14, !15, !16, !17, !18, !19, !20, !21, !22, !23, !24, !25, !26, !27, !28}
-!13 = !{i32 10000, i64 200, i32 2}
-!14 = !{i32 100000, i64 200, i32 2}
-!15 = !{i32 200000, i64 200, i32 2}
-!16 = !{i32 300000, i64 200, i32 2}
-!17 = !{i32 400000, i64 200, i32 2}
-!18 = !{i32 500000, i64 200, i32 2}
-!19 = !{i32 600000, i64 200, i32 2}
-!20 = !{i32 700000, i64 200, i32 2}
-!21 = !{i32 800000, i64 200, i32 2}
-!22 = !{i32 900000, i64 200, i32 2}
-!23 = !{i32 950000, i64 200, i32 2}
-!24 = !{i32 990000, i64 200, i32 2}
-!25 = !{i32 999000, i64 1, i32 5}
-!26 = !{i32 999900, i64 1, i32 5}
-!27 = !{i32 999990, i64 1, i32 5}
-!28 = !{i32 999999, i64 1, i32 5}
-!29 = !{!"function_entry_count", i64 2}
-!30 = !{!"branch_weights", i32 1, i32 201}


        


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