[llvm] 7adb5c2 - Revert "[InstCombine] Fix infinite loop due to bitcast <-> phi transforms"

Nikita Popov via llvm-commits llvm-commits at lists.llvm.org
Tue Dec 31 08:43:18 PST 2019


Author: Nikita Popov
Date: 2019-12-31T17:42:57+01:00
New Revision: 7adb5c2aca8047ae184a96869e3cfcb034fbac39

URL: https://github.com/llvm/llvm-project/commit/7adb5c2aca8047ae184a96869e3cfcb034fbac39
DIFF: https://github.com/llvm/llvm-project/commit/7adb5c2aca8047ae184a96869e3cfcb034fbac39.diff

LOG: Revert "[InstCombine] Fix infinite loop due to bitcast <-> phi transforms"

This reverts commit 27a0795943fee0f30b995fe5165428afc2dfd402.

Seems to break test-suite.

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp

Removed: 
    llvm/test/Transforms/InstCombine/pr44245.ll


################################################################################
diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 446e67580962..3ba56bbe53e0 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -2370,12 +2370,6 @@ Instruction *InstCombiner::optimizeBitCastFromPhi(CastInst &CI, PHINode *PN) {
         llvm_unreachable("all uses should be handled");
       }
     }
-
-    // At this point the old phi has either no users, or is only used
-    // in other old phis. Replace with undef to break circles and remove
-    // the instruction.
-    replaceInstUsesWith(*OldPN, UndefValue::get(OldPN->getType()));
-    eraseInstFromFunction(*OldPN);
   }
 
   return RetVal;

diff  --git a/llvm/test/Transforms/InstCombine/pr44245.ll b/llvm/test/Transforms/InstCombine/pr44245.ll
deleted file mode 100644
index 3b9e252187dc..000000000000
--- a/llvm/test/Transforms/InstCombine/pr44245.ll
+++ /dev/null
@@ -1,142 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -instcombine < %s | FileCheck %s
-
-; This used to cause on infinite instcombine loop.
-
-define void @test(i1 %c) {
-; CHECK-LABEL: @test(
-; CHECK-NEXT:  bb16:
-; CHECK-NEXT:    br i1 [[C:%.*]], label [[BB17:%.*]], label [[BB24:%.*]]
-; CHECK:       bb17:
-; CHECK-NEXT:    [[TMP0:%.*]] = phi i8* [ [[TMP1:%.*]], [[BB47:%.*]] ], [ undef, [[BB16:%.*]] ]
-; CHECK-NEXT:    store i8* [[TMP0]], i8** undef, align 8
-; CHECK-NEXT:    ret void
-; CHECK:       bb24:
-; CHECK-NEXT:    br i1 [[C]], label [[BB44:%.*]], label [[BB49:%.*]]
-; CHECK:       bb44:
-; CHECK-NEXT:    [[TMP469:%.*]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
-; CHECK-NEXT:    br label [[BB47]]
-; CHECK:       bb47:
-; CHECK-NEXT:    [[TMP1]] = phi i8* [ [[TMP2:%.*]], [[BB150:%.*]] ], [ [[TMP1223:%.*]], [[BB119:%.*]] ], [ [[TMP1034:%.*]], [[BB101:%.*]] ], [ [[TMP935:%.*]], [[BB91:%.*]] ], [ [[TMP836:%.*]], [[BB81:%.*]] ], [ [[TMP707:%.*]], [[BB67:%.*]] ], [ [[TMP588:%.*]], [[BB56:%.*]] ], [ [[TMP469]], [[BB44]] ]
-; CHECK-NEXT:    br label [[BB17]]
-; CHECK:       bb49:
-; CHECK-NEXT:    br i1 [[C]], label [[BB56]], label [[BB59:%.*]]
-; CHECK:       bb56:
-; CHECK-NEXT:    [[TMP588]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
-; CHECK-NEXT:    br label [[BB47]]
-; CHECK:       bb59:
-; CHECK-NEXT:    br i1 [[C]], label [[BB67]], label [[BB71:%.*]]
-; CHECK:       bb67:
-; CHECK-NEXT:    [[TMP707]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
-; CHECK-NEXT:    br label [[BB47]]
-; CHECK:       bb71:
-; CHECK-NEXT:    br i1 [[C]], label [[BB81]], label [[BB84:%.*]]
-; CHECK:       bb81:
-; CHECK-NEXT:    [[TMP836]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
-; CHECK-NEXT:    br label [[BB47]]
-; CHECK:       bb84:
-; CHECK-NEXT:    br i1 [[C]], label [[BB91]], label [[BB94:%.*]]
-; CHECK:       bb91:
-; CHECK-NEXT:    [[TMP935]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
-; CHECK-NEXT:    br label [[BB47]]
-; CHECK:       bb94:
-; CHECK-NEXT:    br i1 [[C]], label [[BB101]], label [[BB104:%.*]]
-; CHECK:       bb101:
-; CHECK-NEXT:    [[TMP1034]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
-; CHECK-NEXT:    br label [[BB47]]
-; CHECK:       bb104:
-; CHECK-NEXT:    br i1 [[C]], label [[BB119]], label [[BB123:%.*]]
-; CHECK:       bb119:
-; CHECK-NEXT:    [[TMP1223]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
-; CHECK-NEXT:    br label [[BB47]]
-; CHECK:       bb123:
-; CHECK-NEXT:    br i1 [[C]], label [[BB147:%.*]], label [[BB152:%.*]]
-; CHECK:       bb147:
-; CHECK-NEXT:    [[TMP1492:%.*]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
-; CHECK-NEXT:    br label [[BB150]]
-; CHECK:       bb150:
-; CHECK-NEXT:    [[TMP2]] = phi i8* [ [[TMP1841:%.*]], [[BB152]] ], [ [[TMP1492]], [[BB147]] ]
-; CHECK-NEXT:    br label [[BB47]]
-; CHECK:       bb152:
-; CHECK-NEXT:    [[TMP1841]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
-; CHECK-NEXT:    call void undef()
-; CHECK-NEXT:    br label [[BB150]]
-;
-bb16:                                             ; preds = %bb
-  br i1 %c, label %bb17, label %bb24
-
-bb17:                                             ; preds = %bb47, %bb17
-  %0 = phi i8* [ %1, %bb47 ], [ undef, %bb16 ]
-  store i8* %0, i8** undef, align 8
-  ret void
-
-bb24:                                             ; preds = %bb24
-  br i1 %c, label %bb44, label %bb49
-
-bb44:                                             ; preds = %bb43
-  %tmp46 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
-  br label %bb47
-
-bb47:                                             ; preds = %bb150, %bb119, %bb101, %bb91, %bb81, %bb67, %bb56, %bb44
-  %.in1 = phi i64* [ %.in, %bb150 ], [ %tmp122, %bb119 ], [ %tmp103, %bb101 ], [ %tmp93, %bb91 ], [ %tmp83, %bb81 ], [ %tmp70, %bb67 ], [ %tmp58, %bb56 ], [ %tmp46, %bb44 ]
-  %1 = bitcast i64* %.in1 to i8*
-  br label %bb17
-
-bb49:                                             ; preds = %bb49
-  br i1 %c, label %bb56, label %bb59
-
-bb56:                                             ; preds = %bb55
-  %tmp58 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
-  br label %bb47
-
-bb59:                                             ; preds = %bb59
-  br i1 %c, label %bb67, label %bb71
-
-bb67:                                             ; preds = %bb66
-  %tmp70 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
-  br label %bb47
-
-bb71:                                             ; preds = %bb71
-  br i1 %c, label %bb81, label %bb84
-
-bb81:                                             ; preds = %bb80
-  %tmp83 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
-  br label %bb47
-
-bb84:                                             ; preds = %bb84
-  br i1 %c, label %bb91, label %bb94
-
-bb91:                                             ; preds = %bb90
-  %tmp93 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
-  br label %bb47
-
-bb94:                                            ; preds = %bb94
-  br i1 %c, label %bb101, label %bb104
-
-bb101:                                            ; preds = %bb100
-  %tmp103 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
-  br label %bb47
-
-bb104:                                            ; preds = %bb104
-  br i1 %c, label %bb119, label %bb123
-
-bb119:                                            ; preds = %bb118
-  %tmp122 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
-  br label %bb47
-
-bb123:                                            ; preds = %bb123
-  br i1 %c, label %bb147, label %bb152
-
-bb147:                                            ; preds = %bb146
-  %tmp149 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
-  br label %bb150
-
-bb150:                                            ; preds = %bb152, %bb147
-  %.in = phi i64* [ %tmp184, %bb152 ], [ %tmp149, %bb147 ]
-  br label %bb47
-
-bb152:                                            ; preds = %bb146
-  %tmp184 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
-  call void undef()
-  br label %bb150
-}


        


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