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[LoopSimplifyCFG] Fix SCEV invalidation after removing dead exit (#127536)

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Fixes #127534
This commit is contained in:
Aleksandr Popov 2025-02-21 12:26:39 +01:00 committed by GitHub
parent 6de5d1e46d
commit 41437a6067
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2 changed files with 110 additions and 1 deletions
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2
llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
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@ -369,7 +369,7 @@ private:
DeadInstructions.emplace_back(LandingPad);
for (Instruction *I : DeadInstructions) {
SE.forgetBlockAndLoopDispositions(I);
SE.forgetValue(I);
I->replaceAllUsesWith(PoisonValue::get(I->getType()));
I->eraseFromParent();
}

109
llvm/test/Transforms/LoopSimplifyCFG/pr117537.ll Normal file
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@ -0,0 +1,109 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -S -passes='print<scalar-evolution>,loop-mssa(licm,loop-simplifycfg,loop-predication)' -verify-scev < %s 2>/dev/null | FileCheck %s
; Make sure we don't assert due to insufficient SCEV invalidation.
define i64 @"main"(ptr addrspace(1) %p, i1 %check) {
; CHECK-LABEL: define i64 @main(
; CHECK-SAME: ptr addrspace(1) [[P:%.*]], i1 [[CHECK:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: switch i32 0, label %[[ENTRY_SPLIT:.*]] [
; CHECK-NEXT: i32 1, label %[[LOOP1_PREHEADER_SPLIT_LOOP_EXIT:.*]]
; CHECK-NEXT: ]
; CHECK: [[ENTRY_SPLIT]]:
; CHECK-NEXT: br label %[[LOOP0_PRE:.*]]
; CHECK: [[LOOP0_PRE]]:
; CHECK-NEXT: br i1 [[CHECK]], label %[[EXIT:.*]], label %[[LOOP0:.*]]
; CHECK: [[LOOP0]]:
; CHECK-NEXT: [[LENGTH:%.*]] = load atomic i32, ptr addrspace(1) [[P]] unordered, align 4
; CHECK-NEXT: [[TMP0:%.*]] = icmp ugt i32 [[LENGTH]], 1
; CHECK-NEXT: br i1 [[TMP0]], label %[[LOOP0_OUT:.*]], label %[[LOOP1_PREHEADER_SPLIT_LOOP_EXIT1:.*]]
; CHECK: [[LOOP0_OUT]]:
; CHECK-NEXT: br label %[[LOOP0_PRE]]
; CHECK: [[LOOP1_PREHEADER_SPLIT_LOOP_EXIT]]:
; CHECK-NEXT: [[T_LE:%.*]] = add i32 0, 1
; CHECK-NEXT: br label %[[LOOP1_PREHEADER:.*]]
; CHECK: [[LOOP1_PREHEADER_SPLIT_LOOP_EXIT1]]:
; CHECK-NEXT: [[LENGTH_LCSSA_PH2:%.*]] = phi i32 [ [[LENGTH]], %[[LOOP0]] ]
; CHECK-NEXT: [[LOCAL_PH3:%.*]] = phi i32 [ 0, %[[LOOP0]] ]
; CHECK-NEXT: br label %[[LOOP1_PREHEADER]]
; CHECK: [[LOOP1_PREHEADER]]:
; CHECK-NEXT: [[LENGTH_LCSSA:%.*]] = phi i32 [ poison, %[[LOOP1_PREHEADER_SPLIT_LOOP_EXIT]] ], [ [[LENGTH_LCSSA_PH2]], %[[LOOP1_PREHEADER_SPLIT_LOOP_EXIT1]] ]
; CHECK-NEXT: [[LOCAL:%.*]] = phi i32 [ [[T_LE]], %[[LOOP1_PREHEADER_SPLIT_LOOP_EXIT]] ], [ [[LOCAL_PH3]], %[[LOOP1_PREHEADER_SPLIT_LOOP_EXIT1]] ]
; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[LENGTH_LCSSA]], -1
; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 310, [[TMP1]]
; CHECK-NEXT: [[TMP3:%.*]] = icmp ult i32 4, [[LENGTH_LCSSA]]
; CHECK-NEXT: [[TMP4:%.*]] = and i1 [[TMP3]], [[TMP2]]
; CHECK-NEXT: [[TMP5:%.*]] = freeze i1 [[TMP4]]
; CHECK-NEXT: br label %[[LOOP1:.*]]
; CHECK: [[LOOP1]]:
; CHECK-NEXT: [[IV1:%.*]] = phi i32 [ 4, %[[LOOP1_PREHEADER]] ], [ [[IV1_NEXT:%.*]], %[[LOOP1_GUARDED:.*]] ]
; CHECK-NEXT: [[TMP6:%.*]] = icmp ult i32 [[IV1]], [[LENGTH_LCSSA]]
; CHECK-NEXT: [[WC:%.*]] = call i1 @llvm.experimental.widenable.condition()
; CHECK-NEXT: [[TMP7:%.*]] = and i1 [[TMP5]], [[WC]]
; CHECK-NEXT: br i1 [[TMP7]], label %[[LOOP1_GUARDED]], label %[[DEOPT_EXIT:.*]]
; CHECK: [[LOOP1_GUARDED]]:
; CHECK-NEXT: call void @llvm.assume(i1 [[TMP6]])
; CHECK-NEXT: [[IV1_NEXT]] = add nuw nsw i32 [[IV1]], 1
; CHECK-NEXT: [[CHK:%.*]] = icmp ugt i32 [[IV1]], 310
; CHECK-NEXT: br i1 [[CHK]], label %[[LOOP1_EXIT:.*]], label %[[LOOP1]]
; CHECK: [[DEOPT_EXIT]]:
; CHECK-NEXT: [[TMP8:%.*]] = call i64 (...) @llvm.experimental.deoptimize.i64(i32 13) [ "deopt"() ]
; CHECK-NEXT: ret i64 [[TMP8]]
; CHECK: [[LOOP1_EXIT]]:
; CHECK-NEXT: ret i64 0
; CHECK: [[EXIT]]:
; CHECK-NEXT: ret i64 0
;
entry:
br label %loop0.pre
loop0.pre:
br i1 %check, label %exit, label %loop0
loop0:
%length = load atomic i32, ptr addrspace(1) %p unordered, align 4
%28 = icmp ugt i32 %length, 1
br i1 %28, label %loop0.out, label %loop1.preheader
loop0.out:
%t = add i32 0, 1
br i1 false, label %loop1.preheader, label %mid
loop1.preheader:
%length.lcssa = phi i32 [ %length, %loop0.out ], [ %length, %loop0 ]
%local = phi i32 [ 0, %loop0 ], [ %t, %loop0.out ]
br label %loop1
loop1:
%iv1 = phi i32 [ 4, %loop1.preheader ], [ %iv1.next, %loop1.guarded ]
%82 = icmp ult i32 %iv1, %length.lcssa
%wc = call i1 @llvm.experimental.widenable.condition()
%guard.chk = and i1 %82, %wc
br i1 %guard.chk, label %loop1.guarded, label %deopt-exit
loop1.guarded:
%iv1.next = add nuw nsw i32 %iv1, 1
%chk = icmp ugt i32 %iv1, 310
br i1 %chk, label %loop1.exit, label %loop1
deopt-exit:
%100 = call i64 (...) @llvm.experimental.deoptimize.i64(i32 13) [ "deopt"() ]
ret i64 %100
loop1.exit:
ret i64 0
mid:
br label %loop0.pre
exit:
ret i64 0
}
declare i64 @foo()
declare i64 @llvm.experimental.deoptimize.i64(...)
; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(inaccessiblemem: readwrite)
declare noundef i1 @llvm.experimental.widenable.condition()