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[LVI] Skip self loops in solveBlockValueNonLocal #127763

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Feb 23, 2025
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3 changes: 3 additions & 0 deletions llvm/lib/Analysis/LazyValueInfo.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -694,6 +694,9 @@ LazyValueInfoImpl::solveBlockValueNonLocal(Value *Val, BasicBlock *BB) {
// canonicalizing to make this true rather than relying on this happy
// accident.
for (BasicBlock *Pred : predecessors(BB)) {
// Skip self loops.
if (Pred == BB)
continue;
std::optional<ValueLatticeElement> EdgeResult = getEdgeValue(Val, Pred, BB);
if (!EdgeResult)
// Explore that input, then return here
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39 changes: 39 additions & 0 deletions llvm/test/Transforms/CorrelatedValuePropagation/loop.ll
Original file line number Diff line number Diff line change
@@ -0,0 +1,39 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -passes=correlated-propagation -S %s | FileCheck %s

define i64 @test_self_loop(i64 %x, i1 %cond) {
; CHECK-LABEL: define range(i64 0, 576460752303423488) i64 @test_self_loop(
; CHECK-SAME: i64 [[X:%.*]], i1 [[COND:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*]]:
; CHECK-NEXT: [[COND1:%.*]] = icmp ugt i64 [[X]], 576460752303423487
; CHECK-NEXT: br i1 [[COND1]], label %[[COMMON_RET:.*]], label %[[LOOP:.*]]
; CHECK: [[LOOP]]:
; CHECK-NEXT: br i1 [[COND]], label %[[INDIRECT:.*]], label %[[LOOP]]
; CHECK: [[INDIRECT]]:
; CHECK-NEXT: [[COND2:%.*]] = icmp eq i64 [[X]], 0
; CHECK-NEXT: br i1 [[COND2]], label %[[COMMON_RET]], label %[[EXIT:.*]]
; CHECK: [[EXIT]]:
; CHECK-NEXT: br label %[[COMMON_RET]]
; CHECK: [[COMMON_RET]]:
; CHECK-NEXT: [[RES:%.*]] = phi i64 [ [[X]], %[[EXIT]] ], [ 0, %[[INDIRECT]] ], [ 0, %[[ENTRY]] ]
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
%cond1 = icmp ugt i64 %x, 576460752303423487
br i1 %cond1, label %common.ret, label %loop

loop:
br i1 %cond, label %indirect, label %loop

indirect:
%cond2 = icmp eq i64 %x, 0
br i1 %cond2, label %common.ret, label %exit

exit:
%smax = tail call i64 @llvm.smax.i64(i64 %x, i64 1)
br label %common.ret

common.ret:
%res = phi i64 [ %smax, %exit ], [ 0, %indirect ], [ 0, %entry ]
ret i64 %res
}
18 changes: 7 additions & 11 deletions llvm/test/Transforms/JumpThreading/ddt-crash.ll
Original file line number Diff line number Diff line change
Expand Up @@ -131,20 +131,16 @@ define void @spam(ptr %arg, i1 %arg2) {
; CHECK: bb31:
; CHECK-NEXT: [[TMP32:%.*]] = phi i8 [ [[TMP32]], [[BB31]] ], [ [[TMP32_PR]], [[BB30]] ]
; CHECK-NEXT: [[TMP33:%.*]] = icmp eq i8 [[TMP32]], 0
; CHECK-NEXT: br i1 [[TMP33]], label [[BB31]], label [[BB37]]
; CHECK-NEXT: br i1 [[TMP33]], label [[BB31]], label [[BB41_THREAD]]
; CHECK: bb37:
; CHECK-NEXT: [[TMP36:%.*]] = phi i1 [ false, [[BB23]] ], [ true, [[BB31]] ]
; CHECK-NEXT: [[TMP36:%.*]] = phi i1 [ false, [[BB23]] ]
; CHECK-NEXT: [[TMP38:%.*]] = icmp eq ptr [[TMP15]], null
; CHECK-NEXT: br i1 [[TMP38]], label [[BB39:%.*]], label [[BB41:%.*]]
; CHECK: bb39:
; CHECK-NEXT: [[TMP364:%.*]] = phi i1 [ [[TMP36]], [[BB37]] ]
; CHECK-NEXT: [[TMP40:%.*]] = load ptr, ptr @global, align 8
; CHECK-NEXT: br i1 [[TMP364]], label [[BB41_THREAD]], label [[BB41_THREAD]]
; CHECK-NEXT: br i1 [[TMP38]], label [[BB41:%.*]], label [[BB41_THREAD]]
; CHECK: bb41:
; CHECK-NEXT: [[TMP363:%.*]] = phi i1 [ [[TMP36]], [[BB37]] ]
; CHECK-NEXT: br i1 [[TMP363]], label [[BB41_THREAD]], label [[BB41_THREAD]]
; CHECK: bb41.thread:
; CHECK-NEXT: [[TMP0:%.*]] = phi ptr [ undef, [[BB41]] ], [ undef, [[BB39]] ], [ undef, [[BB39]] ], [ undef, [[BB41]] ], [ undef, [[BB27]] ], [ undef, [[BB25]] ]
; CHECK-NEXT: [[TMP40:%.*]] = load ptr, ptr @global, align 8
; CHECK-NEXT: br label [[BB41_THREAD]]
; CHECK: bb41.thread11:
; CHECK-NEXT: [[TMP0:%.*]] = phi ptr [ undef, [[BB41]] ], [ undef, [[BB25]] ], [ undef, [[BB31]] ], [ undef, [[BB27]] ], [ undef, [[BB37]] ]
; CHECK-NEXT: ret void
;
bb:
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